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LeafOS / LeafOS-Devices / android_kernel_samsung_universal7904 / 501706565b2d4d2d40d0d301d5411ede099b8a6f / . / fs / ext4 / mballoc.c
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/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public Licens
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
*/
/*
* mballoc.c contains the multiblocks allocation routines
*/
#include "mballoc.h"
#include <linux/debugfs.h>
#include <trace/events/ext4.h>
/*
* MUSTDO:
* - test ext4_ext_search_left() and ext4_ext_search_right()
* - search for metadata in few groups
*
* TODO v4:
* - normalization should take into account whether file is still open
* - discard preallocations if no free space left (policy?)
* - don't normalize tails
* - quota
* - reservation for superuser
*
* TODO v3:
* - bitmap read-ahead (proposed by Oleg Drokin aka green)
* - track min/max extents in each group for better group selection
* - mb_mark_used() may allocate chunk right after splitting buddy
* - tree of groups sorted by number of free blocks
* - error handling
*/
/*
* The allocation request involve request for multiple number of blocks
* near to the goal(block) value specified.
*
* During initialization phase of the allocator we decide to use the
* group preallocation or inode preallocation depending on the size of
* the file. The size of the file could be the resulting file size we
* would have after allocation, or the current file size, which ever
* is larger. If the size is less than sbi->s_mb_stream_request we
* select to use the group preallocation. The default value of
* s_mb_stream_request is 16 blocks. This can also be tuned via
* /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
* terms of number of blocks.
*
* The main motivation for having small file use group preallocation is to
* ensure that we have small files closer together on the disk.
*
* First stage the allocator looks at the inode prealloc list,
* ext4_inode_info->i_prealloc_list, which contains list of prealloc
* spaces for this particular inode. The inode prealloc space is
* represented as:
*
* pa_lstart -> the logical start block for this prealloc space
* pa_pstart -> the physical start block for this prealloc space
* pa_len -> lenght for this prealloc space
* pa_free -> free space available in this prealloc space
*
* The inode preallocation space is used looking at the _logical_ start
* block. If only the logical file block falls within the range of prealloc
* space we will consume the particular prealloc space. This make sure that
* that the we have contiguous physical blocks representing the file blocks
*
* The important thing to be noted in case of inode prealloc space is that
* we don't modify the values associated to inode prealloc space except
* pa_free.
*
* If we are not able to find blocks in the inode prealloc space and if we
* have the group allocation flag set then we look at the locality group
* prealloc space. These are per CPU prealloc list repreasented as
*
* ext4_sb_info.s_locality_groups[smp_processor_id()]
*
* The reason for having a per cpu locality group is to reduce the contention
* between CPUs. It is possible to get scheduled at this point.
*
* The locality group prealloc space is used looking at whether we have
* enough free space (pa_free) withing the prealloc space.
*
* If we can't allocate blocks via inode prealloc or/and locality group
* prealloc then we look at the buddy cache. The buddy cache is represented
* by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
* mapped to the buddy and bitmap information regarding different
* groups. The buddy information is attached to buddy cache inode so that
* we can access them through the page cache. The information regarding
* each group is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are stored in the
* inode as:
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information. So for each group we
* take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
* blocksize) blocks. So it can have information regarding groups_per_page
* which is blocks_per_page/2
*
* The buddy cache inode is not stored on disk. The inode is thrown
* away when the filesystem is unmounted.
*
* We look for count number of blocks in the buddy cache. If we were able
* to locate that many free blocks we return with additional information
* regarding rest of the contiguous physical block available
*
* Before allocating blocks via buddy cache we normalize the request
* blocks. This ensure we ask for more blocks that we needed. The extra
* blocks that we get after allocation is added to the respective prealloc
* list. In case of inode preallocation we follow a list of heuristics
* based on file size. This can be found in ext4_mb_normalize_request. If
* we are doing a group prealloc we try to normalize the request to
* sbi->s_mb_group_prealloc. Default value of s_mb_group_prealloc is
* 512 blocks. This can be tuned via
* /sys/fs/ext4/<partition/mb_group_prealloc. The value is represented in
* terms of number of blocks. If we have mounted the file system with -O
* stripe=<value> option the group prealloc request is normalized to the
* stripe value (sbi->s_stripe)
*
* The regular allocator(using the buddy cache) supports few tunables.
*
* /sys/fs/ext4/<partition>/mb_min_to_scan
* /sys/fs/ext4/<partition>/mb_max_to_scan
* /sys/fs/ext4/<partition>/mb_order2_req
*
* The regular allocator uses buddy scan only if the request len is power of
* 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
* value of s_mb_order2_reqs can be tuned via
* /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
* stripe size (sbi->s_stripe), we try to search for contiguous block in
* stripe size. This should result in better allocation on RAID setups. If
* not, we search in the specific group using bitmap for best extents. The
* tunable min_to_scan and max_to_scan control the behaviour here.
* min_to_scan indicate how long the mballoc __must__ look for a best
* extent and max_to_scan indicates how long the mballoc __can__ look for a
* best extent in the found extents. Searching for the blocks starts with
* the group specified as the goal value in allocation context via
* ac_g_ex. Each group is first checked based on the criteria whether it
* can used for allocation. ext4_mb_good_group explains how the groups are
* checked.
*
* Both the prealloc space are getting populated as above. So for the first
* request we will hit the buddy cache which will result in this prealloc
* space getting filled. The prealloc space is then later used for the
* subsequent request.
*/
/*
* mballoc operates on the following data:
* - on-disk bitmap
* - in-core buddy (actually includes buddy and bitmap)
* - preallocation descriptors (PAs)
*
* there are two types of preallocations:
* - inode
* assiged to specific inode and can be used for this inode only.
* it describes part of inode's space preallocated to specific
* physical blocks. any block from that preallocated can be used
* independent. the descriptor just tracks number of blocks left
* unused. so, before taking some block from descriptor, one must
* make sure corresponded logical block isn't allocated yet. this
* also means that freeing any block within descriptor's range
* must discard all preallocated blocks.
* - locality group
* assigned to specific locality group which does not translate to
* permanent set of inodes: inode can join and leave group. space
* from this type of preallocation can be used for any inode. thus
* it's consumed from the beginning to the end.
*
* relation between them can be expressed as:
* in-core buddy = on-disk bitmap + preallocation descriptors
*
* this mean blocks mballoc considers used are:
* - allocated blocks (persistent)
* - preallocated blocks (non-persistent)
*
* consistency in mballoc world means that at any time a block is either
* free or used in ALL structures. notice: "any time" should not be read
* literally -- time is discrete and delimited by locks.
*
* to keep it simple, we don't use block numbers, instead we count number of
* blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
*
* all operations can be expressed as:
* - init buddy: buddy = on-disk + PAs
* - new PA: buddy += N; PA = N
* - use inode PA: on-disk += N; PA -= N
* - discard inode PA buddy -= on-disk - PA; PA = 0
* - use locality group PA on-disk += N; PA -= N
* - discard locality group PA buddy -= PA; PA = 0
* note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
* is used in real operation because we can't know actual used
* bits from PA, only from on-disk bitmap
*
* if we follow this strict logic, then all operations above should be atomic.
* given some of them can block, we'd have to use something like semaphores
* killing performance on high-end SMP hardware. let's try to relax it using
* the following knowledge:
* 1) if buddy is referenced, it's already initialized
* 2) while block is used in buddy and the buddy is referenced,
* nobody can re-allocate that block
* 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
* bit set and PA claims same block, it's OK. IOW, one can set bit in
* on-disk bitmap if buddy has same bit set or/and PA covers corresponded
* block
*
* so, now we're building a concurrency table:
* - init buddy vs.
* - new PA
* blocks for PA are allocated in the buddy, buddy must be referenced
* until PA is linked to allocation group to avoid concurrent buddy init
* - use inode PA
* we need to make sure that either on-disk bitmap or PA has uptodate data
* given (3) we care that PA-=N operation doesn't interfere with init
* - discard inode PA
* the simplest way would be to have buddy initialized by the discard
* - use locality group PA
* again PA-=N must be serialized with init
* - discard locality group PA
* the simplest way would be to have buddy initialized by the discard
* - new PA vs.
* - use inode PA
* i_data_sem serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* some mutex should serialize them
* - discard locality group PA
* discard process must wait until PA isn't used by another process
* - use inode PA
* - use inode PA
* i_data_sem or another mutex should serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* nothing wrong here -- they're different PAs covering different blocks
* - discard locality group PA
* discard process must wait until PA isn't used by another process
*
* now we're ready to make few consequences:
* - PA is referenced and while it is no discard is possible
* - PA is referenced until block isn't marked in on-disk bitmap
* - PA changes only after on-disk bitmap
* - discard must not compete with init. either init is done before
* any discard or they're serialized somehow
* - buddy init as sum of on-disk bitmap and PAs is done atomically
*
* a special case when we've used PA to emptiness. no need to modify buddy
* in this case, but we should care about concurrent init
*
*/
/*
* Logic in few words:
*
* - allocation:
* load group
* find blocks
* mark bits in on-disk bitmap
* release group
*
* - use preallocation:
* find proper PA (per-inode or group)
* load group
* mark bits in on-disk bitmap
* release group
* release PA
*
* - free:
* load group
* mark bits in on-disk bitmap
* release group
*
* - discard preallocations in group:
* mark PAs deleted
* move them onto local list
* load on-disk bitmap
* load group
* remove PA from object (inode or locality group)
* mark free blocks in-core
*
* - discard inode's preallocations:
*/
/*
* Locking rules
*
* Locks:
* - bitlock on a group (group)
* - object (inode/locality) (object)
* - per-pa lock (pa)
*
* Paths:
* - new pa
* object
* group
*
* - find and use pa:
* pa
*
* - release consumed pa:
* pa
* group
* object
*
* - generate in-core bitmap:
* group
* pa
*
* - discard all for given object (inode, locality group):
* object
* pa
* group
*
* - discard all for given group:
* group
* pa
* group
* object
*
*/
static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_ext_cachep;
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);
static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
#if BITS_PER_LONG == 64
*bit += ((unsigned long) addr & 7UL) << 3;
addr = (void *) ((unsigned long) addr & ~7UL);
#elif BITS_PER_LONG == 32
*bit += ((unsigned long) addr & 3UL) << 3;
addr = (void *) ((unsigned long) addr & ~3UL);
#else
#error "how many bits you are?!"
#endif
return addr;
}
static inline int mb_test_bit(int bit, void *addr)
{
/*
* ext4_test_bit on architecture like powerpc
* needs unsigned long aligned address
*/
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_bit(bit, addr);
}
static inline void mb_set_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit(bit, addr);
}
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static inline int mb_find_next_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
BUG_ON(max == NULL);
if (order > e4b->bd_blkbits + 1) {
*max = 0;
return NULL;
}
/* at order 0 we see each particular block */
*max = 1 << (e4b->bd_blkbits + 3);
if (order == 0)
return EXT4_MB_BITMAP(e4b);
bb = EXT4_MB_BUDDY(e4b) + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
return bb;
}
#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int i;
struct super_block *sb = e4b->bd_sb;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
for (i = 0; i < count; i++) {
if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
ext4_fsblk_t blocknr;
blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
blocknr += first + i;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_grp_locked_error(sb, e4b->bd_group,
__func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr,
first + i, e4b->bd_group);
}
mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
int i;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
for (i = 0; i < count; i++) {
BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
b2 = (unsigned char *) bitmap;
for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
if (b1[i] != b2[i]) {
printk(KERN_ERR "corruption in group %u "
"at byte %u(%u): %x in copy != %x "
"on disk/prealloc\n",
e4b->bd_group, i, i * 8, b1[i], b2[i]);
BUG();
}
}
}
}
#else
static inline void mb_free_blocks_double(struct inode *inode,
struct ext4_buddy *e4b, int first, int count)
{
return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
int first, int count)
{
return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
return;
}
#endif
#ifdef AGGRESSIVE_CHECK
#define MB_CHECK_ASSERT(assert) \
do { \
if (!(assert)) { \
printk(KERN_EMERG \
"Assertion failure in %s() at %s:%d: \"%s\"\n", \
function, file, line, # assert); \
BUG(); \
} \
} while (0)
static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
const char *function, int line)
{
struct super_block *sb = e4b->bd_sb;
int order = e4b->bd_blkbits + 1;
int max;
int max2;
int i;
int j;
int k;
int count;
struct ext4_group_info *grp;
int fragments = 0;
int fstart;
struct list_head *cur;
void *buddy;
void *buddy2;
{
static int mb_check_counter;
if (mb_check_counter++ % 100 != 0)
return 0;
}
while (order > 1) {
buddy = mb_find_buddy(e4b, order, &max);
MB_CHECK_ASSERT(buddy);
buddy2 = mb_find_buddy(e4b, order - 1, &max2);
MB_CHECK_ASSERT(buddy2);
MB_CHECK_ASSERT(buddy != buddy2);
MB_CHECK_ASSERT(max * 2 == max2);
count = 0;
for (i = 0; i < max; i++) {
if (mb_test_bit(i, buddy)) {
/* only single bit in buddy2 may be 1 */
if (!mb_test_bit(i << 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit((i<<1)+1, buddy2));
} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit(i << 1, buddy2));
}
continue;
}
/* both bits in buddy2 must be 0 */
MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
for (j = 0; j < (1 << order); j++) {
k = (i * (1 << order)) + j;
MB_CHECK_ASSERT(
!mb_test_bit(k, EXT4_MB_BITMAP(e4b)));
}
count++;
}
MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
order--;
}
fstart = -1;
buddy = mb_find_buddy(e4b, 0, &max);
for (i = 0; i < max; i++) {
if (!mb_test_bit(i, buddy)) {
MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
if (fstart == -1) {
fragments++;
fstart = i;
}
continue;
}
fstart = -1;
/* check used bits only */
for (j = 0; j < e4b->bd_blkbits + 1; j++) {
buddy2 = mb_find_buddy(e4b, j, &max2);
k = i >> j;
MB_CHECK_ASSERT(k < max2);
MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
}
}
MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
grp = ext4_get_group_info(sb, e4b->bd_group);
buddy = mb_find_buddy(e4b, 0, &max);
list_for_each(cur, &grp->bb_prealloc_list) {
ext4_group_t groupnr;
struct ext4_prealloc_space *pa;
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
MB_CHECK_ASSERT(groupnr == e4b->bd_group);
for (i = 0; i < pa->pa_len; i++)
MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
}
return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
__FILE__, __func__, __LINE__)
#else
#define mb_check_buddy(e4b)
#endif
/* FIXME!! need more doc */
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t min;
ext4_grpblk_t max;
ext4_grpblk_t chunk;
unsigned short border;
BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
border = 2 << sb->s_blocksize_bits;
while (len > 0) {
/* find how many blocks can be covered since this position */
max = ffs(first | border) - 1;
/* find how many blocks of power 2 we need to mark */
min = fls(len) - 1;
if (max < min)
min = max;
chunk = 1 << min;
/* mark multiblock chunks only */
grp->bb_counters[min]++;
if (min > 0)
mb_clear_bit(first >> min,
buddy + sbi->s_mb_offsets[min]);
len -= chunk;
first += chunk;
}
}
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
ext4_grpblk_t max = EXT4_BLOCKS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_grpblk_t first;
ext4_grpblk_t len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
/* initialize buddy from bitmap which is aggregation
* of on-disk bitmap and preallocations */
i = mb_find_next_zero_bit(bitmap, max, 0);
grp->bb_first_free = i;
while (i < max) {
fragments++;
first = i;
i = mb_find_next_bit(bitmap, max, i);
len = i - first;
free += len;
if (len > 1)
ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
else
grp->bb_counters[0]++;
if (i < max)
i = mb_find_next_zero_bit(bitmap, max, i);
}
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
ext4_grp_locked_error(sb, group, __func__,
"EXT4-fs: group %u: %u blocks in bitmap, %u in gd",
group, free, grp->bb_free);
/*
* If we intent to continue, we consider group descritor
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
}
clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
period = get_cycles() - period;
spin_lock(&EXT4_SB(sb)->s_bal_lock);
EXT4_SB(sb)->s_mb_buddies_generated++;
EXT4_SB(sb)->s_mb_generation_time += period;
spin_unlock(&EXT4_SB(sb)->s_bal_lock);
}
/* The buddy information is attached the buddy cache inode
* for convenience. The information regarding each group
* is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are
* stored in the inode as
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information.
* So for each group we take up 2 blocks. A page can
* contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks.
* So it can have information regarding groups_per_page which
* is blocks_per_page/2
*/
static int ext4_mb_init_cache(struct page *page, char *incore)
{
ext4_group_t ngroups;
int blocksize;
int blocks_per_page;
int groups_per_page;
int err = 0;
int i;
ext4_group_t first_group;
int first_block;
struct super_block *sb;
struct buffer_head *bhs;
struct buffer_head **bh;
struct inode *inode;
char *data;
char *bitmap;
mb_debug(1, "init page %lu\n", page->index);
inode = page->mapping->host;
sb = inode->i_sb;
ngroups = ext4_get_groups_count(sb);
blocksize = 1 << inode->i_blkbits;
blocks_per_page = PAGE_CACHE_SIZE / blocksize;
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* allocate buffer_heads to read bitmaps */
if (groups_per_page > 1) {
err = -ENOMEM;
i = sizeof(struct buffer_head *) * groups_per_page;
bh = kzalloc(i, GFP_NOFS);
if (bh == NULL)
goto out;
} else
bh = &bhs;
first_group = page->index * blocks_per_page / 2;
/* read all groups the page covers into the cache */
for (i = 0; i < groups_per_page; i++) {
struct ext4_group_desc *desc;
if (first_group + i >= ngroups)
break;
err = -EIO;
desc = ext4_get_group_desc(sb, first_group + i, NULL);
if (desc == NULL)
goto out;
err = -ENOMEM;
bh[i] = sb_getblk(sb, ext4_block_bitmap(sb, desc));
if (bh[i] == NULL)
goto out;
if (bitmap_uptodate(bh[i]))
continue;
lock_buffer(bh[i]);
if (bitmap_uptodate(bh[i])) {
unlock_buffer(bh[i]);
continue;
}
ext4_lock_group(sb, first_group + i);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
ext4_init_block_bitmap(sb, bh[i],
first_group + i, desc);
set_bitmap_uptodate(bh[i]);
set_buffer_uptodate(bh[i]);
ext4_unlock_group(sb, first_group + i);
unlock_buffer(bh[i]);
continue;
}
ext4_unlock_group(sb, first_group + i);
if (buffer_uptodate(bh[i])) {
/*
* if not uninit if bh is uptodate,
* bitmap is also uptodate
*/
set_bitmap_uptodate(bh[i]);
unlock_buffer(bh[i]);
continue;
}
get_bh(bh[i]);
/*
* submit the buffer_head for read. We can
* safely mark the bitmap as uptodate now.
* We do it here so the bitmap uptodate bit
* get set with buffer lock held.
*/
set_bitmap_uptodate(bh[i]);
bh[i]->b_end_io = end_buffer_read_sync;
submit_bh(READ, bh[i]);
mb_debug(1, "read bitmap for group %u\n", first_group + i);
}
/* wait for I/O completion */
for (i = 0; i < groups_per_page && bh[i]; i++)
wait_on_buffer(bh[i]);
err = -EIO;
for (i = 0; i < groups_per_page && bh[i]; i++)
if (!buffer_uptodate(bh[i]))
goto out;
err = 0;
first_block = page->index * blocks_per_page;
/* init the page */
memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
for (i = 0; i < blocks_per_page; i++) {
int group;
struct ext4_group_info *grinfo;
group = (first_block + i) >> 1;
if (group >= ngroups)
break;
/*
* data carry information regarding this
* particular group in the format specified
* above
*
*/
data = page_address(page) + (i * blocksize);
bitmap = bh[group - first_group]->b_data;
/*
* We place the buddy block and bitmap block
* close together
*/
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug(1, "put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
grinfo = ext4_get_group_info(sb, group);
grinfo->bb_fragments = 0;
memset(grinfo->bb_counters, 0,
sizeof(*grinfo->bb_counters) *
(sb->s_blocksize_bits+2));
/*
* incore got set to the group block bitmap below
*/
ext4_lock_group(sb, group);
ext4_mb_generate_buddy(sb, data, incore, group);
ext4_unlock_group(sb, group);
incore = NULL;
} else {
/* this is block of bitmap */
BUG_ON(incore != NULL);
mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
/* see comments in ext4_mb_put_pa() */
ext4_lock_group(sb, group);
memcpy(data, bitmap, blocksize);
/* mark all preallocated blks used in in-core bitmap */
ext4_mb_generate_from_pa(sb, data, group);
ext4_mb_generate_from_freelist(sb, data, group);
ext4_unlock_group(sb, group);
/* set incore so that the buddy information can be
* generated using this
*/
incore = data;
}
}
SetPageUptodate(page);
out:
if (bh) {
for (i = 0; i < groups_per_page && bh[i]; i++)
brelse(bh[i]);
if (bh != &bhs)
kfree(bh);
}
return err;
}
static noinline_for_stack
int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
{
int ret = 0;
void *bitmap;
int blocks_per_page;
int block, pnum, poff;
int num_grp_locked = 0;
struct ext4_group_info *this_grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
struct page *page = NULL, *bitmap_page = NULL;
mb_debug(1, "init group %u\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
this_grp = ext4_get_group_info(sb, group);
/*
* This ensures that we don't reinit the buddy cache
* page which map to the group from which we are already
* allocating. If we are looking at the buddy cache we would
* have taken a reference using ext4_mb_load_buddy and that
* would have taken the alloc_sem lock.
*/
num_grp_locked = ext4_mb_get_buddy_cache_lock(sb, group);
if (!EXT4_MB_GRP_NEED_INIT(this_grp)) {
/*
* somebody initialized the group
* return without doing anything
*/
ret = 0;
goto err;
}
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
ret = ext4_mb_init_cache(page, NULL);
if (ret) {
unlock_page(page);
goto err;
}
unlock_page(page);
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
mark_page_accessed(page);
bitmap_page = page;
bitmap = page_address(page) + (poff * sb->s_blocksize);
/* init buddy cache */
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page == bitmap_page) {
/*
* If both the bitmap and buddy are in
* the same page we don't need to force
* init the buddy
*/
unlock_page(page);
} else if (page) {
BUG_ON(page->mapping != inode->i_mapping);
ret = ext4_mb_init_cache(page, bitmap);
if (ret) {
unlock_page(page);
goto err;
}
unlock_page(page);
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
mark_page_accessed(page);
err:
ext4_mb_put_buddy_cache_lock(sb, group, num_grp_locked);
if (bitmap_page)
page_cache_release(bitmap_page);
if (page)
page_cache_release(page);
return ret;
}
static noinline_for_stack int
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b)
{
int blocks_per_page;
int block;
int pnum;
int poff;
struct page *page;
int ret;
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
mb_debug(1, "load group %u\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
grp = ext4_get_group_info(sb, group);
e4b->bd_blkbits = sb->s_blocksize_bits;
e4b->bd_info = ext4_get_group_info(sb, group);
e4b->bd_sb = sb;
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
e4b->alloc_semp = &grp->alloc_sem;
/* Take the read lock on the group alloc
* sem. This would make sure a parallel
* ext4_mb_init_group happening on other
* groups mapped by the page is blocked
* till we are done with allocation
*/
repeat_load_buddy:
down_read(e4b->alloc_semp);
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
/* we need to check for group need init flag
* with alloc_semp held so that we can be sure
* that new blocks didn't get added to the group
* when we are loading the buddy cache
*/
up_read(e4b->alloc_semp);
/*
* we need full data about the group
* to make a good selection
*/
ret = ext4_mb_init_group(sb, group);
if (ret)
return ret;
goto repeat_load_buddy;
}
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
/* we could use find_or_create_page(), but it locks page
* what we'd like to avoid in fast path ... */
page = find_get_page(inode->i_mapping, pnum);
if (page == NULL || !PageUptodate(page)) {
if (page)
/*
* drop the page reference and try
* to get the page with lock. If we
* are not uptodate that implies
* somebody just created the page but
* is yet to initialize the same. So
* wait for it to initialize.
*/
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, NULL);
if (ret) {
unlock_page(page);
goto err;
}
mb_cmp_bitmaps(e4b, page_address(page) +
(poff * sb->s_blocksize));
}
unlock_page(page);
}
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
mark_page_accessed(page);
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page == NULL || !PageUptodate(page)) {
if (page)
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
if (ret) {
unlock_page(page);
goto err;
}
}
unlock_page(page);
}
}
if (page == NULL || !PageUptodate(page)) {
ret = -EIO;
goto err;
}
e4b->bd_buddy_page = page;
e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
mark_page_accessed(page);
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
return 0;
err:
if (e4b->bd_bitmap_page)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
/* Done with the buddy cache */
up_read(e4b->alloc_semp);
return ret;
}
static void ext4_mb_release_desc(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
/* Done with the buddy cache */
if (e4b->alloc_semp)
up_read(e4b->alloc_semp);
}
static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
{
int order = 1;
void *bb;
BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
bb = EXT4_MB_BUDDY(e4b);
while (order <= e4b->bd_blkbits + 1) {
block = block >> 1;
if (!mb_test_bit(block, bb)) {
/* this block is part of buddy of order 'order' */
return order;
}
bb += 1 << (e4b->bd_blkbits - order);
order++;
}
return 0;
}
static void mb_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
*addr = 0;
cur += 32;
continue;
}
mb_clear_bit(cur, bm);
cur++;
}
}
static void mb_set_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: set whole word at once */
addr = bm + (cur >> 3);
*addr = 0xffffffff;
cur += 32;
continue;
}
mb_set_bit(cur, bm);
cur++;
}
}
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int block = 0;
int max = 0;
int order;
void *buddy;
void *buddy2;
struct super_block *sb = e4b->bd_sb;
BUG_ON(first + count > (sb->s_blocksize << 3));
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_free_blocks_double(inode, e4b, first, count);
e4b->bd_info->bb_free += count;
if (first < e4b->bd_info->bb_first_free)
e4b->bd_info->bb_first_free = first;
/* let's maintain fragments counter */
if (first != 0)
block = !mb_test_bit(first - 1, EXT4_MB_BITMAP(e4b));
if (first + count < EXT4_SB(sb)->s_mb_maxs[0])
max = !mb_test_bit(first + count, EXT4_MB_BITMAP(e4b));
if (block && max)
e4b->bd_info->bb_fragments--;
else if (!block && !max)
e4b->bd_info->bb_fragments++;
/* let's maintain buddy itself */
while (count-- > 0) {
block = first++;
order = 0;
if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
ext4_fsblk_t blocknr;
blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
blocknr += block;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_grp_locked_error(sb, e4b->bd_group,
__func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr, block,
e4b->bd_group);
}
mb_clear_bit(block, EXT4_MB_BITMAP(e4b));
e4b->bd_info->bb_counters[order]++;
/* start of the buddy */
buddy = mb_find_buddy(e4b, order, &max);
do {
block &= ~1UL;
if (mb_test_bit(block, buddy) ||
mb_test_bit(block + 1, buddy))
break;
/* both the buddies are free, try to coalesce them */
buddy2 = mb_find_buddy(e4b, order + 1, &max);
if (!buddy2)
break;
if (order > 0) {
/* for special purposes, we don't set
* free bits in bitmap */
mb_set_bit(block, buddy);
mb_set_bit(block + 1, buddy);
}
e4b->bd_info->bb_counters[order]--;
e4b->bd_info->bb_counters[order]--;
block = block >> 1;
order++;
e4b->bd_info->bb_counters[order]++;
mb_clear_bit(block, buddy2);
buddy = buddy2;
} while (1);
}
mb_check_buddy(e4b);
}
static int mb_find_extent(struct ext4_buddy *e4b, int order, int block,
int needed, struct ext4_free_extent *ex)
{
int next = block;
int max;
int ord;
void *buddy;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
BUG_ON(ex == NULL);
buddy = mb_find_buddy(e4b, order, &max);
BUG_ON(buddy == NULL);
BUG_ON(block >= max);
if (mb_test_bit(block, buddy)) {
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
return 0;
}
/* FIXME dorp order completely ? */
if (likely(order == 0)) {
/* find actual order */
order = mb_find_order_for_block(e4b, block);
block = block >> order;
}
ex->fe_len = 1 << order;
ex->fe_start = block << order;
ex->fe_group = e4b->bd_group;
/* calc difference from given start */
next = next - ex->fe_start;
ex->fe_len -= next;
ex->fe_start += next;
while (needed > ex->fe_len &&
(buddy = mb_find_buddy(e4b, order, &max))) {
if (block + 1 >= max)
break;
next = (block + 1) * (1 << order);
if (mb_test_bit(next, EXT4_MB_BITMAP(e4b)))
break;
ord = mb_find_order_for_block(e4b, next);
order = ord;
block = next >> order;
ex->fe_len += 1 << order;
}
BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
return ex->fe_len;
}
static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
{
int ord;
int mlen = 0;
int max = 0;
int cur;
int start = ex->fe_start;
int len = ex->fe_len;
unsigned ret = 0;
int len0 = len;
void *buddy;
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
BUG_ON(e4b->bd_group != ex->fe_group);
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_mark_used_double(e4b, start, len);
e4b->bd_info->bb_free -= len;
if (e4b->bd_info->bb_first_free == start)
e4b->bd_info->bb_first_free += len;
/* let's maintain fragments counter */
if (start != 0)
mlen = !mb_test_bit(start - 1, EXT4_MB_BITMAP(e4b));
if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
max = !mb_test_bit(start + len, EXT4_MB_BITMAP(e4b));
if (mlen && max)
e4b->bd_info->bb_fragments++;
else if (!mlen && !max)
e4b->bd_info->bb_fragments--;
/* let's maintain buddy itself */
while (len) {
ord = mb_find_order_for_block(e4b, start);
if (((start >> ord) << ord) == start && len >= (1 << ord)) {
/* the whole chunk may be allocated at once! */
mlen = 1 << ord;
buddy = mb_find_buddy(e4b, ord, &max);
BUG_ON((start >> ord) >= max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
start += mlen;
len -= mlen;
BUG_ON(len < 0);
continue;
}
/* store for history */
if (ret == 0)
ret = len | (ord << 16);
/* we have to split large buddy */
BUG_ON(ord <= 0);
buddy = mb_find_buddy(e4b, ord, &max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
ord--;
cur = (start >> ord) & ~1U;
buddy = mb_find_buddy(e4b, ord, &max);
mb_clear_bit(cur, buddy);
mb_clear_bit(cur + 1, buddy);
e4b->bd_info->bb_counters[ord]++;
e4b->bd_info->bb_counters[ord]++;
}
mb_set_bits(EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
mb_check_buddy(e4b);
return ret;
}
/*
* Must be called under group lock!
*/
static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int ret;
BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
ret = mb_mark_used(e4b, &ac->ac_b_ex);
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_tail = ret & 0xffff;
ac->ac_buddy = ret >> 16;
/*
* take the page reference. We want the page to be pinned
* so that we don't get a ext4_mb_init_cache_call for this
* group until we update the bitmap. That would mean we
* double allocate blocks. The reference is dropped
* in ext4_mb_release_context
*/
ac->ac_bitmap_page = e4b->bd_bitmap_page;
get_page(ac->ac_bitmap_page);
ac->ac_buddy_page = e4b->bd_buddy_page;
get_page(ac->ac_buddy_page);
/* on allocation we use ac to track the held semaphore */
ac->alloc_semp = e4b->alloc_semp;
e4b->alloc_semp = NULL;
/* store last allocated for subsequent stream allocation */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
spin_lock(&sbi->s_md_lock);
sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
spin_unlock(&sbi->s_md_lock);
}
}
/*
* regular allocator, for general purposes allocation
*/
static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b,
int finish_group)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
struct ext4_free_extent ex;
int max;
if (ac->ac_status == AC_STATUS_FOUND)
return;
/*
* We don't want to scan for a whole year
*/
if (ac->ac_found > sbi->s_mb_max_to_scan &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
ac->ac_status = AC_STATUS_BREAK;
return;
}
/*
* Haven't found good chunk so far, let's continue
*/
if (bex->fe_len < gex->fe_len)
return;
if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
&& bex->fe_group == e4b->bd_group) {
/* recheck chunk's availability - we don't know
* when it was found (within this lock-unlock
* period or not) */
max = mb_find_extent(e4b, 0, bex->fe_start, gex->fe_len, &ex);
if (max >= gex->fe_len) {
ext4_mb_use_best_found(ac, e4b);
return;
}
}
}
/*
* The routine checks whether found extent is good enough. If it is,
* then the extent gets marked used and flag is set to the context
* to stop scanning. Otherwise, the extent is compared with the
* previous found extent and if new one is better, then it's stored
* in the context. Later, the best found extent will be used, if
* mballoc can't find good enough extent.
*
* FIXME: real allocation policy is to be designed yet!
*/
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
struct ext4_free_extent *ex,
struct ext4_buddy *e4b)
{
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
BUG_ON(ex->fe_len <= 0);
BUG_ON(ex->fe_len > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
BUG_ON(ex->fe_start >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
ac->ac_found++;
/*
* The special case - take what you catch first
*/
if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* Let's check whether the chuck is good enough
*/
if (ex->fe_len == gex->fe_len) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* If this is first found extent, just store it in the context
*/
if (bex->fe_len == 0) {
*bex = *ex;
return;
}
/*
* If new found extent is better, store it in the context
*/
if (bex->fe_len < gex->fe_len) {
/* if the request isn't satisfied, any found extent
* larger than previous best one is better */
if (ex->fe_len > bex->fe_len)
*bex = *ex;
} else if (ex->fe_len > gex->fe_len) {
/* if the request is satisfied, then we try to find
* an extent that still satisfy the request, but is
* smaller than previous one */
if (ex->fe_len < bex->fe_len)
*bex = *ex;
}
ext4_mb_check_limits(ac, e4b, 0);
}
static noinline_for_stack
int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_free_extent ex = ac->ac_b_ex;
ext4_group_t group = ex.fe_group;
int max;
int err;
BUG_ON(ex.fe_len <= 0);
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, 0, ex.fe_start, ex.fe_len, &ex);
if (max > 0) {
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_release_desc(e4b);
return 0;
}
static noinline_for_stack
int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
ext4_group_t group = ac->ac_g_ex.fe_group;
int max;
int err;
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_super_block *es = sbi->s_es;
struct ext4_free_extent ex;
if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
return 0;
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, 0, ac->ac_g_ex.fe_start,
ac->ac_g_ex.fe_len, &ex);
if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
ext4_fsblk_t start;
start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
ex.fe_start + le32_to_cpu(es->s_first_data_block);
/* use do_div to get remainder (would be 64-bit modulo) */
if (do_div(start, sbi->s_stripe) == 0) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
} else if (max >= ac->ac_g_ex.fe_len) {
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
/* Sometimes, caller may want to merge even small
* number of blocks to an existing extent */
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_release_desc(e4b);
return 0;
}
/*
* The routine scans buddy structures (not bitmap!) from given order
* to max order and tries to find big enough chunk to satisfy the req
*/
static noinline_for_stack
void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_group_info *grp = e4b->bd_info;
void *buddy;
int i;
int k;
int max;
BUG_ON(ac->ac_2order <= 0);
for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
if (grp->bb_counters[i] == 0)
continue;
buddy = mb_find_buddy(e4b, i, &max);
BUG_ON(buddy == NULL);
k = mb_find_next_zero_bit(buddy, max, 0);
BUG_ON(k >= max);
ac->ac_found++;
ac->ac_b_ex.fe_len = 1 << i;
ac->ac_b_ex.fe_start = k << i;
ac->ac_b_ex.fe_group = e4b->bd_group;
ext4_mb_use_best_found(ac, e4b);
BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
if (EXT4_SB(sb)->s_mb_stats)
atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
break;
}
}
/*
* The routine scans the group and measures all found extents.
* In order to optimize scanning, caller must pass number of
* free blocks in the group, so the routine can know upper limit.
*/
static noinline_for_stack
void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
void *bitmap = EXT4_MB_BITMAP(e4b);
struct ext4_free_extent ex;
int i;
int free;
free = e4b->bd_info->bb_free;
BUG_ON(free <= 0);
i = e4b->bd_info->bb_first_free;
while (free && ac->ac_status == AC_STATUS_CONTINUE) {
i = mb_find_next_zero_bit(bitmap,
EXT4_BLOCKS_PER_GROUP(sb), i);
if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
/*
* IF we have corrupt bitmap, we won't find any
* free blocks even though group info says we
* we have free blocks
*/
ext4_grp_locked_error(sb, e4b->bd_group,
__func__, "%d free blocks as per "
"group info. But bitmap says 0",
free);
break;
}
mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
BUG_ON(ex.fe_len <= 0);
if (free < ex.fe_len) {
ext4_grp_locked_error(sb, e4b->bd_group,
__func__, "%d free blocks as per "
"group info. But got %d blocks",
free, ex.fe_len);
/*
* The number of free blocks differs. This mostly
* indicate that the bitmap is corrupt. So exit
* without claiming the space.
*/
break;
}
ext4_mb_measure_extent(ac, &ex, e4b);
i += ex.fe_len;
free -= ex.fe_len;
}
ext4_mb_check_limits(ac, e4b, 1);
}
/*
* This is a special case for storages like raid5
* we try to find stripe-aligned chunks for stripe-size requests
* XXX should do so at least for multiples of stripe size as well
*/
static noinline_for_stack
void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
void *bitmap = EXT4_MB_BITMAP(e4b);
struct ext4_free_extent ex;
ext4_fsblk_t first_group_block;
ext4_fsblk_t a;
ext4_grpblk_t i;
int max;
BUG_ON(sbi->s_stripe == 0);
/* find first stripe-aligned block in group */
first_group_block = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
+ le32_to_cpu(sbi->s_es->s_first_data_block);
a = first_group_block + sbi->s_stripe - 1;
do_div(a, sbi->s_stripe);
i = (a * sbi->s_stripe) - first_group_block;
while (i < EXT4_BLOCKS_PER_GROUP(sb)) {
if (!mb_test_bit(i, bitmap)) {
max = mb_find_extent(e4b, 0, i, sbi->s_stripe, &ex);
if (max >= sbi->s_stripe) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
break;
}
}
i += sbi->s_stripe;
}
}
static int ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, int cr)
{
unsigned free, fragments;
unsigned i, bits;
int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
BUG_ON(cr < 0 || cr >= 4);
BUG_ON(EXT4_MB_GRP_NEED_INIT(grp));
free = grp->bb_free;
fragments = grp->bb_fragments;
if (free == 0)
return 0;
if (fragments == 0)
return 0;
switch (cr) {
case 0:
BUG_ON(ac->ac_2order == 0);
/* Avoid using the first bg of a flexgroup for data files */
if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
(flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
((group % flex_size) == 0))
return 0;
bits = ac->ac_sb->s_blocksize_bits + 1;
for (i = ac->ac_2order; i <= bits; i++)
if (grp->bb_counters[i] > 0)
return 1;
break;
case 1:
if ((free / fragments) >= ac->ac_g_ex.fe_len)
return 1;
break;
case 2:
if (free >= ac->ac_g_ex.fe_len)
return 1;
break;
case 3:
return 1;
default:
BUG();
}
return 0;
}
/*
* lock the group_info alloc_sem of all the groups
* belonging to the same buddy cache page. This
* make sure other parallel operation on the buddy
* cache doesn't happen whild holding the buddy cache
* lock
*/
int ext4_mb_get_buddy_cache_lock(struct super_block *sb, ext4_group_t group)
{
int i;
int block, pnum;
int blocks_per_page;
int groups_per_page;
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t first_group;
struct ext4_group_info *grp;
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
first_group = pnum * blocks_per_page / 2;
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* read all groups the page covers into the cache */
for (i = 0; i < groups_per_page; i++) {
if ((first_group + i) >= ngroups)
break;
grp = ext4_get_group_info(sb, first_group + i);
/* take all groups write allocation
* semaphore. This make sure there is
* no block allocation going on in any
* of that groups
*/
down_write_nested(&grp->alloc_sem, i);
}
return i;
}
void ext4_mb_put_buddy_cache_lock(struct super_block *sb,
ext4_group_t group, int locked_group)
{
int i;
int block, pnum;
int blocks_per_page;
ext4_group_t first_group;
struct ext4_group_info *grp;
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
first_group = pnum * blocks_per_page / 2;
/* release locks on all the groups */
for (i = 0; i < locked_group; i++) {
grp = ext4_get_group_info(sb, first_group + i);
/* take all groups write allocation
* semaphore. This make sure there is
* no block allocation going on in any
* of that groups
*/
up_write(&grp->alloc_sem);
}
}
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t ngroups, group, i;
int cr;
int err = 0;
int bsbits;
struct ext4_sb_info *sbi;
struct super_block *sb;
struct ext4_buddy e4b;
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
ngroups = ext4_get_groups_count(sb);
/* non-extent files are limited to low blocks/groups */
if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL))
ngroups = sbi->s_blockfile_groups;
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
/* first, try the goal */
err = ext4_mb_find_by_goal(ac, &e4b);
if (err || ac->ac_status == AC_STATUS_FOUND)
goto out;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
goto out;
/*
* ac->ac2_order is set only if the fe_len is a power of 2
* if ac2_order is set we also set criteria to 0 so that we
* try exact allocation using buddy.
*/
i = fls(ac->ac_g_ex.fe_len);
ac->ac_2order = 0;
/*
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
*/
if (i >= sbi->s_mb_order2_reqs) {
/*
* This should tell if fe_len is exactly power of 2
*/
if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
ac->ac_2order = i - 1;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* if stream allocation is enabled, use global goal */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
/* TBD: may be hot point */
spin_lock(&sbi->s_md_lock);
ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
spin_unlock(&sbi->s_md_lock);
}
/* Let's just scan groups to find more-less suitable blocks */
cr = ac->ac_2order ? 0 : 1;
/*
* cr == 0 try to get exact allocation,
* cr == 3 try to get anything
*/
repeat:
for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
/*
* searching for the right group start
* from the goal value specified
*/
group = ac->ac_g_ex.fe_group;
for (i = 0; i < ngroups; group++, i++) {
struct ext4_group_info *grp;
struct ext4_group_desc *desc;
if (group == ngroups)
group = 0;
/* quick check to skip empty groups */
grp = ext4_get_group_info(sb, group);
if (grp->bb_free == 0)
continue;
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err)
goto out;
ext4_lock_group(sb, group);
if (!ext4_mb_good_group(ac, group, cr)) {
/* someone did allocation from this group */
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
continue;
}
ac->ac_groups_scanned++;
desc = ext4_get_group_desc(sb, group, NULL);
if (cr == 0)
ext4_mb_simple_scan_group(ac, &e4b);
else if (cr == 1 &&
ac->ac_g_ex.fe_len == sbi->s_stripe)
ext4_mb_scan_aligned(ac, &e4b);
else
ext4_mb_complex_scan_group(ac, &e4b);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
}
if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
/*
* We've been searching too long. Let's try to allocate
* the best chunk we've found so far
*/
ext4_mb_try_best_found(ac, &e4b);
if (ac->ac_status != AC_STATUS_FOUND) {
/*
* Someone more lucky has already allocated it.
* The only thing we can do is just take first
* found block(s)
printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
*/
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_flags |= EXT4_MB_HINT_FIRST;
cr = 3;
atomic_inc(&sbi->s_mb_lost_chunks);
goto repeat;
}
}
out:
return err;
}
static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
struct super_block *sb = seq->private;
ext4_group_t group;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = seq->private;
ext4_group_t group;
++*pos;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
struct super_block *sb = seq->private;
ext4_group_t group = (ext4_group_t) ((unsigned long) v);
int i;
int err;
struct ext4_buddy e4b;
struct sg {
struct ext4_group_info info;
ext4_grpblk_t counters[16];
} sg;
group--;
if (group == 0)
seq_printf(seq, "#%-5s: %-5s %-5s %-5s "
"[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s "
"%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n",
"group", "free", "frags", "first",
"2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6",
"2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13");
i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
sizeof(struct ext4_group_info);
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
seq_printf(seq, "#%-5u: I/O error\n", group);
return 0;
}
ext4_lock_group(sb, group);
memcpy(&sg, ext4_get_group_info(sb, group), i);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
sg.info.bb_fragments, sg.info.bb_first_free);
for (i = 0; i <= 13; i++)
seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
sg.info.bb_counters[i] : 0);
seq_printf(seq, " ]\n");
return 0;
}
static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
{
}
static const struct seq_operations ext4_mb_seq_groups_ops = {
.start = ext4_mb_seq_groups_start,
.next = ext4_mb_seq_groups_next,
.stop = ext4_mb_seq_groups_stop,
.show = ext4_mb_seq_groups_show,
};
static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
{
struct super_block *sb = PDE(inode)->data;
int rc;
rc = seq_open(file, &ext4_mb_seq_groups_ops);
if (rc == 0) {
struct seq_file *m = (struct seq_file *)file->private_data;
m->private = sb;
}
return rc;
}
static const struct file_operations ext4_mb_seq_groups_fops = {
.owner = THIS_MODULE,
.open = ext4_mb_seq_groups_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i, len;
int metalen = 0;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_info **meta_group_info;
/*
* First check if this group is the first of a reserved block.
* If it's true, we have to allocate a new table of pointers
* to ext4_group_info structures
*/
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
metalen = sizeof(*meta_group_info) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
meta_group_info = kmalloc(metalen, GFP_KERNEL);
if (meta_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
"buddy group\n");
goto exit_meta_group_info;
}
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
meta_group_info;
}
/*
* calculate needed size. if change bb_counters size,
* don't forget about ext4_mb_generate_buddy()
*/
len = offsetof(typeof(**meta_group_info),
bb_counters[sb->s_blocksize_bits + 2]);
meta_group_info =
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
meta_group_info[i] = kzalloc(len, GFP_KERNEL);
if (meta_group_info[i] == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
goto exit_group_info;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[i]->bb_state));
/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
meta_group_info[i]->bb_free =
ext4_free_blocks_after_init(sb, group, desc);
} else {
meta_group_info[i]->bb_free =
ext4_free_blks_count(sb, desc);
}
INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
init_rwsem(&meta_group_info[i]->alloc_sem);
meta_group_info[i]->bb_free_root.rb_node = NULL;
#ifdef DOUBLE_CHECK
{
struct buffer_head *bh;
meta_group_info[i]->bb_bitmap =
kmalloc(sb->s_blocksize, GFP_KERNEL);
BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
bh = ext4_read_block_bitmap(sb, group);
BUG_ON(bh == NULL);
memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
sb->s_blocksize);
put_bh(bh);
}
#endif
return 0;
exit_group_info:
/* If a meta_group_info table has been allocated, release it now */
if (group % EXT4_DESC_PER_BLOCK(sb) == 0)
kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
exit_meta_group_info:
return -ENOMEM;
} /* ext4_mb_add_groupinfo */
static int ext4_mb_init_backend(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
int num_meta_group_infos;
int num_meta_group_infos_max;
int array_size;
struct ext4_group_desc *desc;
/* This is the number of blocks used by GDT */
num_meta_group_infos = (ngroups + EXT4_DESC_PER_BLOCK(sb) -
1) >> EXT4_DESC_PER_BLOCK_BITS(sb);
/*
* This is the total number of blocks used by GDT including
* the number of reserved blocks for GDT.
* The s_group_info array is allocated with this value
* to allow a clean online resize without a complex
* manipulation of pointer.
* The drawback is the unused memory when no resize
* occurs but it's very low in terms of pages
* (see comments below)
* Need to handle this properly when META_BG resizing is allowed
*/
num_meta_group_infos_max = num_meta_group_infos +
le16_to_cpu(es->s_reserved_gdt_blocks);
/*
* array_size is the size of s_group_info array. We round it
* to the next power of two because this approximation is done
* internally by kmalloc so we can have some more memory
* for free here (e.g. may be used for META_BG resize).
*/
array_size = 1;
while (array_size < sizeof(*sbi->s_group_info) *
num_meta_group_infos_max)
array_size = array_size << 1;
/* An 8TB filesystem with 64-bit pointers requires a 4096 byte
* kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
* So a two level scheme suffices for now. */
sbi->s_group_info = kmalloc(array_size, GFP_KERNEL);
if (sbi->s_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n");
return -ENOMEM;
}
sbi->s_buddy_cache = new_inode(sb);
if (sbi->s_buddy_cache == NULL) {
printk(KERN_ERR "EXT4-fs: can't get new inode\n");
goto err_freesgi;
}
EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
for (i = 0; i < ngroups; i++) {
desc = ext4_get_group_desc(sb, i, NULL);
if (desc == NULL) {
printk(KERN_ERR
"EXT4-fs: can't read descriptor %u\n", i);
goto err_freebuddy;
}
if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
goto err_freebuddy;
}
return 0;
err_freebuddy:
while (i-- > 0)
kfree(ext4_get_group_info(sb, i));
i = num_meta_group_infos;
while (i-- > 0)
kfree(sbi->s_group_info[i]);
iput(sbi->s_buddy_cache);
err_freesgi:
kfree(sbi->s_group_info);
return -ENOMEM;
}
int ext4_mb_init(struct super_block *sb, int needs_recovery)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned i, j;
unsigned offset;
unsigned max;
int ret;
i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_offsets == NULL) {
return -ENOMEM;
}
i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_maxs == NULL) {
kfree(sbi->s_mb_offsets);
return -ENOMEM;
}
/* order 0 is regular bitmap */
sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
sbi->s_mb_offsets[0] = 0;
i = 1;
offset = 0;
max = sb->s_blocksize << 2;
do {
sbi->s_mb_offsets[i] = offset;
sbi->s_mb_maxs[i] = max;
offset += 1 << (sb->s_blocksize_bits - i);
max = max >> 1;
i++;
} while (i <= sb->s_blocksize_bits + 1);
/* init file for buddy data */
ret = ext4_mb_init_backend(sb);
if (ret != 0) {
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
return ret;
}
spin_lock_init(&sbi->s_md_lock);
spin_lock_init(&sbi->s_bal_lock);
sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
sbi->s_mb_stats = MB_DEFAULT_STATS;
sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
if (sbi->s_locality_groups == NULL) {
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
return -ENOMEM;
}
for_each_possible_cpu(i) {
struct ext4_locality_group *lg;
lg = per_cpu_ptr(sbi->s_locality_groups, i);
mutex_init(&lg->lg_mutex);
for (j = 0; j < PREALLOC_TB_SIZE; j++)
INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
spin_lock_init(&lg->lg_prealloc_lock);
}
if (sbi->s_proc)
proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
&ext4_mb_seq_groups_fops, sb);
if (sbi->s_journal)
sbi->s_journal->j_commit_callback = release_blocks_on_commit;
return 0;
}
/* need to called with the ext4 group lock held */
static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
struct ext4_prealloc_space *pa;
struct list_head *cur, *tmp;
int count = 0;
list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
list_del(&pa->pa_group_list);
count++;
kmem_cache_free(ext4_pspace_cachep, pa);
}
if (count)
mb_debug(1, "mballoc: %u PAs left\n", count);
}
int ext4_mb_release(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
int num_meta_group_infos;
struct ext4_group_info *grinfo;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (sbi->s_group_info) {
for (i = 0; i < ngroups; i++) {
grinfo = ext4_get_group_info(sb, i);
#ifdef DOUBLE_CHECK
kfree(grinfo->bb_bitmap);
#endif
ext4_lock_group(sb, i);
ext4_mb_cleanup_pa(grinfo);
ext4_unlock_group(sb, i);
kfree(grinfo);
}
num_meta_group_infos = (ngroups +
EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
for (i = 0; i < num_meta_group_infos; i++)
kfree(sbi->s_group_info[i]);
kfree(sbi->s_group_info);
}
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
if (sbi->s_buddy_cache)
iput(sbi->s_buddy_cache);
if (sbi->s_mb_stats) {
printk(KERN_INFO
"EXT4-fs: mballoc: %u blocks %u reqs (%u success)\n",
atomic_read(&sbi->s_bal_allocated),
atomic_read(&sbi->s_bal_reqs),
atomic_read(&sbi->s_bal_success));
printk(KERN_INFO
"EXT4-fs: mballoc: %u extents scanned, %u goal hits, "
"%u 2^N hits, %u breaks, %u lost\n",
atomic_read(&sbi->s_bal_ex_scanned),
atomic_read(&sbi->s_bal_goals),
atomic_read(&sbi->s_bal_2orders),
atomic_read(&sbi->s_bal_breaks),
atomic_read(&sbi->s_mb_lost_chunks));
printk(KERN_INFO
"EXT4-fs: mballoc: %lu generated and it took %Lu\n",
sbi->s_mb_buddies_generated++,
sbi->s_mb_generation_time);
printk(KERN_INFO
"EXT4-fs: mballoc: %u preallocated, %u discarded\n",
atomic_read(&sbi->s_mb_preallocated),
atomic_read(&sbi->s_mb_discarded));
}
free_percpu(sbi->s_locality_groups);
if (sbi->s_proc)
remove_proc_entry("mb_groups", sbi->s_proc);
return 0;
}
/*
* This function is called by the jbd2 layer once the commit has finished,
* so we know we can free the blocks that were released with that commit.
*/
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
{
struct super_block *sb = journal->j_private;
struct ext4_buddy e4b;
struct ext4_group_info *db;
int err, count = 0, count2 = 0;
struct ext4_free_data *entry;
struct list_head *l, *ltmp;
list_for_each_safe(l, ltmp, &txn->t_private_list) {
entry = list_entry(l, struct ext4_free_data, list);
mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
entry->count, entry->group, entry);
err = ext4_mb_load_buddy(sb, entry->group, &e4b);
/* we expect to find existing buddy because it's pinned */
BUG_ON(err != 0);
db = e4b.bd_info;
/* there are blocks to put in buddy to make them really free */
count += entry->count;
count2++;
ext4_lock_group(sb, entry->group);
/* Take it out of per group rb tree */
rb_erase(&entry->node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count);
if (!db->bb_free_root.rb_node) {
/* No more items in the per group rb tree
* balance refcounts from ext4_mb_free_metadata()
*/
page_cache_release(e4b.bd_buddy_page);
page_cache_release(e4b.bd_bitmap_page);
}
ext4_unlock_group(sb, entry->group);
if (test_opt(sb, DISCARD)) {
ext4_fsblk_t discard_block;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
discard_block = (ext4_fsblk_t)entry->group *
EXT4_BLOCKS_PER_GROUP(sb)
+ entry->start_blk
+ le32_to_cpu(es->s_first_data_block);
trace_ext4_discard_blocks(sb,
(unsigned long long)discard_block,
entry->count);
sb_issue_discard(sb, discard_block, entry->count);
}
kmem_cache_free(ext4_free_ext_cachep, entry);
ext4_mb_release_desc(&e4b);
}
mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
}
#ifdef CONFIG_EXT4_DEBUG
u8 mb_enable_debug __read_mostly;
static struct dentry *debugfs_dir;
static struct dentry *debugfs_debug;
static void __init ext4_create_debugfs_entry(void)
{
debugfs_dir = debugfs_create_dir("ext4", NULL);
if (debugfs_dir)
debugfs_debug = debugfs_create_u8("mballoc-debug",
S_IRUGO | S_IWUSR,
debugfs_dir,
&mb_enable_debug);
}
static void ext4_remove_debugfs_entry(void)
{
debugfs_remove(debugfs_debug);
debugfs_remove(debugfs_dir);
}
#else
static void __init ext4_create_debugfs_entry(void)
{
}
static void ext4_remove_debugfs_entry(void)
{
}
#endif
int __init init_ext4_mballoc(void)
{
ext4_pspace_cachep =
kmem_cache_create("ext4_prealloc_space",
sizeof(struct ext4_prealloc_space),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_pspace_cachep == NULL)
return -ENOMEM;
ext4_ac_cachep =
kmem_cache_create("ext4_alloc_context",
sizeof(struct ext4_allocation_context),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_ac_cachep == NULL) {
kmem_cache_destroy(ext4_pspace_cachep);
return -ENOMEM;
}
ext4_free_ext_cachep =
kmem_cache_create("ext4_free_block_extents",
sizeof(struct ext4_free_data),
0, SLAB_RECLAIM_ACCOUNT, NULL);
if (ext4_free_ext_cachep == NULL) {
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
return -ENOMEM;
}
ext4_create_debugfs_entry();
return 0;
}
void exit_ext4_mballoc(void)
{
/*
* Wait for completion of call_rcu()'s on ext4_pspace_cachep
* before destroying the slab cache.
*/
rcu_barrier();
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_ext_cachep);
ext4_remove_debugfs_entry();
}
/*
* Check quota and mark choosed space (ac->ac_b_ex) non-free in bitmaps
* Returns 0 if success or error code
*/
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
handle_t *handle, unsigned int reserv_blks)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_super_block *es;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block;
int err, len;
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(ac->ac_b_ex.fe_len <= 0);
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
es = sbi->s_es;
err = -EIO;
bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
if (!bitmap_bh)
goto out_err;
err = ext4_journal_get_write_access(handle, bitmap_bh);
if (err)
goto out_err;
err = -EIO;
gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
if (!gdp)
goto out_err;
ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
ext4_free_blks_count(sb, gdp));
err = ext4_journal_get_write_access(handle, gdp_bh);
if (err)
goto out_err;
block = ac->ac_b_ex.fe_group * EXT4_BLOCKS_PER_GROUP(sb)
+ ac->ac_b_ex.fe_start
+ le32_to_cpu(es->s_first_data_block);
len = ac->ac_b_ex.fe_len;
if (!ext4_data_block_valid(sbi, block, len)) {
ext4_error(sb, __func__,
"Allocating blocks %llu-%llu which overlap "
"fs metadata\n", block, block+len);
/* File system mounted not to panic on error
* Fix the bitmap and repeat the block allocation
* We leak some of the blocks here.
*/
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (!err)
err = -EAGAIN;
goto out_err;
}
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
bitmap_bh->b_data));
}
}
#endif
mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,ac->ac_b_ex.fe_len);
if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_blks_set(sb, gdp,
ext4_free_blocks_after_init(sb,
ac->ac_b_ex.fe_group, gdp));
}
len = ext4_free_blks_count(sb, gdp) - ac->ac_b_ex.fe_len;
ext4_free_blks_set(sb, gdp, len);
gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
/*
* Now reduce the dirty block count also. Should not go negative
*/
if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
else {
percpu_counter_sub(&sbi->s_dirtyblocks_counter,
ac->ac_b_ex.fe_len);
/* convert reserved quota blocks to real quota blocks */
vfs_dq_claim_block(ac->ac_inode, ac->ac_b_ex.fe_len);
}
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
atomic_sub(ac->ac_b_ex.fe_len,
&sbi->s_flex_groups[flex_group].free_blocks);
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (err)
goto out_err;
err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
out_err:
sb->s_dirt = 1;
brelse(bitmap_bh);
return err;
}
/*
* here we normalize request for locality group
* Group request are normalized to s_strip size if we set the same via mount
* option. If not we set it to s_mb_group_prealloc which can be configured via
* /sys/fs/ext4/<partition>/mb_group_prealloc
*
* XXX: should we try to preallocate more than the group has now?
*/
static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
BUG_ON(lg == NULL);
if (EXT4_SB(sb)->s_stripe)
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;
else
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
mb_debug(1, "#%u: goal %u blocks for locality group\n",
current->pid, ac->ac_g_ex.fe_len);
}
/*
* Normalization means making request better in terms of
* size and alignment
*/
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
int bsbits, max;
ext4_lblk_t end;
loff_t size, orig_size, start_off;
ext4_lblk_t start, orig_start;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *pa;
/* do normalize only data requests, metadata requests
do not need preallocation */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
/* sometime caller may want exact blocks */
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
/* caller may indicate that preallocation isn't
* required (it's a tail, for example) */
if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
return;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
ext4_mb_normalize_group_request(ac);
return ;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* first, let's learn actual file size
* given current request is allocated */
size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
size = size << bsbits;
if (size < i_size_read(ac->ac_inode))
size = i_size_read(ac->ac_inode);
/* max size of free chunks */
max = 2 << bsbits;
#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
(req <= (size) || max <= (chunk_size))
/* first, try to predict filesize */
/* XXX: should this table be tunable? */
start_off = 0;
if (size <= 16 * 1024) {
size = 16 * 1024;
} else if (size <= 32 * 1024) {
size = 32 * 1024;
} else if (size <= 64 * 1024) {
size = 64 * 1024;
} else if (size <= 128 * 1024) {
size = 128 * 1024;
} else if (size <= 256 * 1024) {
size = 256 * 1024;
} else if (size <= 512 * 1024) {
size = 512 * 1024;
} else if (size <= 1024 * 1024) {
size = 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(21 - bsbits)) << 21;
size = 2 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(22 - bsbits)) << 22;
size = 4 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
(8<<20)>>bsbits, max, 8 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(23 - bsbits)) << 23;
size = 8 * 1024 * 1024;
} else {
start_off = (loff_t)ac->ac_o_ex.fe_logical << bsbits;
size = ac->ac_o_ex.fe_len << bsbits;
}
orig_size = size = size >> bsbits;
orig_start = start = start_off >> bsbits;
/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
size -= ar->lleft + 1 - start;
start = ar->lleft + 1;
}
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
end = start + size;
/* check we don't cross already preallocated blocks */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
if (pa->pa_deleted)
continue;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
pa_end = pa->pa_lstart + pa->pa_len;
/* PA must not overlap original request */
BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
ac->ac_o_ex.fe_logical < pa->pa_lstart));
/* skip PAs this normalized request doesn't overlap with */
if (pa->pa_lstart >= end || pa_end <= start) {
spin_unlock(&pa->pa_lock);
continue;
}
BUG_ON(pa->pa_lstart <= start && pa_end >= end);
/* adjust start or end to be adjacent to this pa */
if (pa_end <= ac->ac_o_ex.fe_logical) {
BUG_ON(pa_end < start);
start = pa_end;
} else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
BUG_ON(pa->pa_lstart > end);
end = pa->pa_lstart;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
size = end - start;
/* XXX: extra loop to check we really don't overlap preallocations */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0) {
pa_end = pa->pa_lstart + pa->pa_len;
BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
if (start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical) {
printk(KERN_ERR "start %lu, size %lu, fe_logical %lu\n",
(unsigned long) start, (unsigned long) size,
(unsigned long) ac->ac_o_ex.fe_logical);
}
BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical);
BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
/* now prepare goal request */
/* XXX: is it better to align blocks WRT to logical
* placement or satisfy big request as is */
ac->ac_g_ex.fe_logical = start;
ac->ac_g_ex.fe_len = size;
/* define goal start in order to merge */
if (ar->pright && (ar->lright == (start + size))) {
/* merge to the right */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
if (ar->pleft && (ar->lleft + 1 == start)) {
/* merge to the left */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
(unsigned) orig_size, (unsigned) start);
}
static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
atomic_inc(&sbi->s_bal_reqs);
atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
if (ac->ac_o_ex.fe_len >= ac->ac_g_ex.fe_len)
atomic_inc(&sbi->s_bal_success);
atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
atomic_inc(&sbi->s_bal_goals);
if (ac->ac_found > sbi->s_mb_max_to_scan)
atomic_inc(&sbi->s_bal_breaks);
}
if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
trace_ext4_mballoc_alloc(ac);
else
trace_ext4_mballoc_prealloc(ac);
}
/*
* Called on failure; free up any blocks from the inode PA for this
* context. We don't need this for MB_GROUP_PA because we only change
* pa_free in ext4_mb_release_context(), but on failure, we've already
* zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
*/
static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
int len;
if (pa && pa->pa_type == MB_INODE_PA) {
len = ac->ac_b_ex.fe_len;
pa->pa_free += len;
}
}
/*
* use blocks preallocated to inode
*/
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
ext4_fsblk_t start;
ext4_fsblk_t end;
int len;
/* found preallocated blocks, use them */
start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
len = end - start;
ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
BUG_ON(start < pa->pa_pstart);
BUG_ON(start + len > pa->pa_pstart + pa->pa_len);
BUG_ON(pa->pa_free < len);
pa->pa_free -= len;
mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
}
/*
* use blocks preallocated to locality group
*/
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
unsigned int len = ac->ac_o_ex.fe_len;
ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
&ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
/* we don't correct pa_pstart or pa_plen here to avoid
* possible race when the group is being loaded concurrently
* instead we correct pa later, after blocks are marked
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
}
/*
* Return the prealloc space that have minimal distance
* from the goal block. @cpa is the prealloc
* space that is having currently known minimal distance
* from the goal block.
*/
static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
struct ext4_prealloc_space *pa,
struct ext4_prealloc_space *cpa)
{
ext4_fsblk_t cur_distance, new_distance;
if (cpa == NULL) {
atomic_inc(&pa->pa_count);
return pa;
}
cur_distance = abs(goal_block - cpa->pa_pstart);
new_distance = abs(goal_block - pa->pa_pstart);
if (cur_distance < new_distance)
return cpa;
/* drop the previous reference */
atomic_dec(&cpa->pa_count);
atomic_inc(&pa->pa_count);
return pa;
}
/*
* search goal blocks in preallocated space
*/
static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
{
int order, i;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa, *cpa = NULL;
ext4_fsblk_t goal_block;
/* only data can be preallocated */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return 0;
/* first, try per-file preallocation */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
/* all fields in this condition don't change,
* so we can skip locking for them */
if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)
continue;
/* non-extent files can't have physical blocks past 2^32 */
if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL) &&
pa->pa_pstart + pa->pa_len > EXT4_MAX_BLOCK_FILE_PHYS)
continue;
/* found preallocated blocks, use them */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 && pa->pa_free) {
atomic_inc(&pa->pa_count);
ext4_mb_use_inode_pa(ac, pa);
spin_unlock(&pa->pa_lock);
ac->ac_criteria = 10;
rcu_read_unlock();
return 1;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
/* can we use group allocation? */
if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
return 0;
/* inode may have no locality group for some reason */
lg = ac->ac_lg;
if (lg == NULL)
return 0;
order = fls(ac->ac_o_ex.fe_len) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
goal_block = ac->ac_g_ex.fe_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
ac->ac_g_ex.fe_start +
le32_to_cpu(EXT4_SB(ac->ac_sb)->s_es->s_first_data_block);
/*
* search for the prealloc space that is having
* minimal distance from the goal block.
*/
for (i = order; i < PREALLOC_TB_SIZE; i++) {
rcu_read_lock();
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
pa_inode_list) {
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 &&
pa->pa_free >= ac->ac_o_ex.fe_len) {
cpa = ext4_mb_check_group_pa(goal_block,
pa, cpa);
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
}
if (cpa) {
ext4_mb_use_group_pa(ac, cpa);
ac->ac_criteria = 20;
return 1;
}
return 0;
}
/*
* the function goes through all block freed in the group
* but not yet committed and marks them used in in-core bitmap.
* buddy must be generated from this bitmap
* Need to be called with the ext4 group lock held
*/
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct rb_node *n;
struct ext4_group_info *grp;
struct ext4_free_data *entry;
grp = ext4_get_group_info(sb, group);
n = rb_first(&(grp->bb_free_root));
while (n) {
entry = rb_entry(n, struct ext4_free_data, node);
mb_set_bits(bitmap, entry->start_blk, entry->count);
n = rb_next(n);
}
return;
}
/*
* the function goes through all preallocation in this group and marks them
* used in in-core bitmap. buddy must be generated from this bitmap
* Need to be called with ext4 group lock held
*/
static noinline_for_stack
void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_prealloc_space *pa;
struct list_head *cur;
ext4_group_t groupnr;
ext4_grpblk_t start;
int preallocated = 0;
int count = 0;
int len;
/* all form of preallocation discards first load group,
* so the only competing code is preallocation use.
* we don't need any locking here
* notice we do NOT ignore preallocations with pa_deleted
* otherwise we could leave used blocks available for
* allocation in buddy when concurrent ext4_mb_put_pa()
* is dropping preallocation
*/
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
&groupnr, &start);
len = pa->pa_len;
spin_unlock(&pa->pa_lock);
if (unlikely(len == 0))
continue;
BUG_ON(groupnr != group);
mb_set_bits(bitmap, start, len);
preallocated += len;
count++;
}
mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
}
static void ext4_mb_pa_callback(struct rcu_head *head)
{
struct ext4_prealloc_space *pa;
pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
kmem_cache_free(ext4_pspace_cachep, pa);
}
/*
* drops a reference to preallocated space descriptor
* if this was the last reference and the space is consumed
*/
static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
struct super_block *sb, struct ext4_prealloc_space *pa)
{
ext4_group_t grp;
ext4_fsblk_t grp_blk;
if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
return;
/* in this short window concurrent discard can set pa_deleted */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 1) {
spin_unlock(&pa->pa_lock);
return;
}
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
grp_blk = pa->pa_pstart;
/*
* If doing group-based preallocation, pa_pstart may be in the
* next group when pa is used up
*/
if (pa->pa_type == MB_GROUP_PA)
grp_blk--;
ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
/*
* possible race:
*
* P1 (buddy init) P2 (regular allocation)
* find block B in PA
* copy on-disk bitmap to buddy
* mark B in on-disk bitmap
* drop PA from group
* mark all PAs in buddy
*
* thus, P1 initializes buddy with B available. to prevent this
* we make "copy" and "mark all PAs" atomic and serialize "drop PA"
* against that pair
*/
ext4_lock_group(sb, grp);
list_del(&pa->pa_group_list);
ext4_unlock_group(sb, grp);
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
/*
* creates new preallocated space for given inode
*/
static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
struct ext4_inode_info *ei;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
if (pa == NULL)
return -ENOMEM;
if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
int winl;
int wins;
int win;
int offs;
/* we can't allocate as much as normalizer wants.
* so, found space must get proper lstart
* to cover original request */
BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
/* we're limited by original request in that
* logical block must be covered any way
* winl is window we can move our chunk within */
winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
/* also, we should cover whole original request */
wins = ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len;
/* the smallest one defines real window */
win = min(winl, wins);
offs = ac->ac_o_ex.fe_logical % ac->ac_b_ex.fe_len;
if (offs && offs < win)
win = offs;
ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical - win;
BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
}
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_lstart = ac->ac_b_ex.fe_logical;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
atomic_set(&pa->pa_count, 1);
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_inode_list);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_INODE_PA;
mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_inode_pa(ac, pa);
ext4_mb_use_inode_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
ei = EXT4_I(ac->ac_inode);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
pa->pa_obj_lock = &ei->i_prealloc_lock;
pa->pa_inode = ac->ac_inode;
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
spin_lock(pa->pa_obj_lock);
list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
spin_unlock(pa->pa_obj_lock);
return 0;
}
/*
* creates new preallocated space for locality group inodes belongs to
*/
static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ext4_pspace_cachep == NULL);
pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
if (pa == NULL)
return -ENOMEM;
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_lstart = pa->pa_pstart;
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
atomic_set(&pa->pa_count, 1);
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_inode_list);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_GROUP_PA;
mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_group_pa(ac, pa);
ext4_mb_use_group_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
lg = ac->ac_lg;
BUG_ON(lg == NULL);
pa->pa_obj_lock = &lg->lg_prealloc_lock;
pa->pa_inode = NULL;
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
/*
* We will later add the new pa to the right bucket
* after updating the pa_free in ext4_mb_release_context
*/
return 0;
}
static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
{
int err;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
err = ext4_mb_new_group_pa(ac);
else
err = ext4_mb_new_inode_pa(ac);
return err;
}
/*
* finds all unused blocks in on-disk bitmap, frees them in
* in-core bitmap and buddy.
* @pa must be unlinked from inode and group lists, so that
* nobody else can find/use it.
* the caller MUST hold group/inode locks.
* TODO: optimize the case when there are no in-core structures yet
*/
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
{
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned int end;
unsigned int next;
ext4_group_t group;
ext4_grpblk_t bit;
unsigned long long grp_blk_start;
sector_t start;
int err = 0;
int free = 0;
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
grp_blk_start = pa->pa_pstart - bit;
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
end = bit + pa->pa_len;
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = pa->pa_inode;
}
while (bit < end) {
bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
if (bit >= end)
break;
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
le32_to_cpu(sbi->s_es->s_first_data_block);
mb_debug(1, " free preallocated %u/%u in group %u\n",
(unsigned) start, (unsigned) next - bit,
(unsigned) group);
free += next - bit;
if (ac) {
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = next - bit;
ac->ac_b_ex.fe_logical = 0;
trace_ext4_mballoc_discard(ac);
}
trace_ext4_mb_release_inode_pa(ac, pa, grp_blk_start + bit,
next - bit);
mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
bit = next + 1;
}
if (free != pa->pa_free) {
printk(KERN_CRIT "pa %p: logic %lu, phys. %lu, len %lu\n",
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
(unsigned long) pa->pa_len);
ext4_grp_locked_error(sb, group,
__func__, "free %u, pa_free %u",
free, pa->pa_free);
/*
* pa is already deleted so we use the value obtained
* from the bitmap and continue.
*/
}
atomic_add(free, &sbi->s_mb_discarded);
return err;
}
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
struct ext4_prealloc_space *pa,
struct ext4_allocation_context *ac)
{
struct super_block *sb = e4b->bd_sb;
ext4_group_t group;
ext4_grpblk_t bit;
trace_ext4_mb_release_group_pa(ac, pa);
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = NULL;
ac->ac_b_ex.fe_group = group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = pa->pa_len;
ac->ac_b_ex.fe_logical = 0;
trace_ext4_mballoc_discard(ac);
}
return 0;
}
/*
* releases all preallocations in given group
*
* first, we need to decide discard policy:
* - when do we discard
* 1) ENOSPC
* - how many do we discard
* 1) how many requested
*/
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_group_t group, int needed)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
struct list_head list;
struct ext4_buddy e4b;
int err;
int busy = 0;
int free = 0;
mb_debug(1, "discard preallocation for group %u\n", group);
if (list_empty(&grp->bb_prealloc_list))
return 0;
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (bitmap_bh == NULL) {
ext4_error(sb, __func__, "Error in reading block "
"bitmap for %u", group);
return 0;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
put_bh(bitmap_bh);
return 0;
}
if (needed == 0)
needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;
INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac)
ac->ac_sb = sb;
repeat:
ext4_lock_group(sb, group);
list_for_each_entry_safe(pa, tmp,
&grp->bb_prealloc_list, pa_group_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
spin_unlock(&pa->pa_lock);
busy = 1;
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* seems this one can be freed ... */
pa->pa_deleted = 1;
/* we can trust pa_free ... */
free += pa->pa_free;
spin_unlock(&pa->pa_lock);
list_del(&pa->pa_group_list);
list_add(&pa->u.pa_tmp_list, &list);
}
/* if we still need more blocks and some PAs were used, try again */
if (free < needed && busy) {
busy = 0;
ext4_unlock_group(sb, group);
/*
* Yield the CPU here so that we don't get soft lockup
* in non preempt case.
*/
yield();
goto repeat;
}
/* found anything to free? */
if (list_empty(&list)) {
BUG_ON(free != 0);
goto out;
}
/* now free all selected PAs */
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
/* remove from object (inode or locality group) */
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
if (pa->pa_type == MB_GROUP_PA)
ext4_mb_release_group_pa(&e4b, pa, ac);
else
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
out:
ext4_unlock_group(sb, group);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
ext4_mb_release_desc(&e4b);
put_bh(bitmap_bh);
return free;
}
/*
* releases all non-used preallocated blocks for given inode
*
* It's important to discard preallocations under i_data_sem
* We don't want another block to be served from the prealloc
* space when we are discarding the inode prealloc space.
*
* FIXME!! Make sure it is valid at all the call sites
*/
void ext4_discard_preallocations(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct super_block *sb = inode->i_sb;
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
ext4_group_t group = 0;
struct list_head list;
struct ext4_buddy e4b;
int err;
if (!S_ISREG(inode->i_mode)) {
/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
return;
}
mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
trace_ext4_discard_preallocations(inode);
INIT_LIST_HEAD(&list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
ac->ac_sb = sb;
ac->ac_inode = inode;
}
repeat:
/* first, collect all pa's in the inode */
spin_lock(&ei->i_prealloc_lock);
while (!list_empty(&ei->i_prealloc_list)) {
pa = list_entry(ei->i_prealloc_list.next,
struct ext4_prealloc_space, pa_inode_list);
BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/* this shouldn't happen often - nobody should
* use preallocation while we're discarding it */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
printk(KERN_ERR "uh-oh! used pa while discarding\n");
WARN_ON(1);
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
if (pa->pa_deleted == 0) {
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &list);
continue;
}
/* someone is deleting pa right now */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
/* we have to wait here because pa_deleted
* doesn't mean pa is already unlinked from
* the list. as we might be called from
* ->clear_inode() the inode will get freed
* and concurrent thread which is unlinking
* pa from inode's list may access already
* freed memory, bad-bad-bad */
/* XXX: if this happens too often, we can
* add a flag to force wait only in case
* of ->clear_inode(), but not in case of
* regular truncate */
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
spin_unlock(&ei->i_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
BUG_ON(pa->pa_type != MB_INODE_PA);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
continue;
}
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (bitmap_bh == NULL) {
ext4_error(sb, __func__, "Error in reading block "
"bitmap for %u", group);
ext4_mb_release_desc(&e4b);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
put_bh(bitmap_bh);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}
/*
* finds all preallocated spaces and return blocks being freed to them
* if preallocated space becomes full (no block is used from the space)
* then the function frees space in buddy
* XXX: at the moment, truncate (which is the only way to free blocks)
* discards all preallocations
*/
static void ext4_mb_return_to_preallocation(struct inode *inode,
struct ext4_buddy *e4b,
sector_t block, int count)
{
BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list));
}
#ifdef CONFIG_EXT4_DEBUG
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
ext4_group_t ngroups, i;
printk(KERN_ERR "EXT4-fs: Can't allocate:"
" Allocation context details:\n");
printk(KERN_ERR "EXT4-fs: status %d flags %d\n",
ac->ac_status, ac->ac_flags);
printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
"best %lu/%lu/%lu@%lu cr %d\n",
(unsigned long)ac->ac_o_ex.fe_group,
(unsigned long)ac->ac_o_ex.fe_start,
(unsigned long)ac->ac_o_ex.fe_len,
(unsigned long)ac->ac_o_ex.fe_logical,
(unsigned long)ac->ac_g_ex.fe_group,
(unsigned long)ac->ac_g_ex.fe_start,
(unsigned long)ac->ac_g_ex.fe_len,
(unsigned long)ac->ac_g_ex.fe_logical,
(unsigned long)ac->ac_b_ex.fe_group,
(unsigned long)ac->ac_b_ex.fe_start,
(unsigned long)ac->ac_b_ex.fe_len,
(unsigned long)ac->ac_b_ex.fe_logical,
(int)ac->ac_criteria);
printk(KERN_ERR "EXT4-fs: %lu scanned, %d found\n", ac->ac_ex_scanned,
ac->ac_found);
printk(KERN_ERR "EXT4-fs: groups: \n");
ngroups = ext4_get_groups_count(sb);
for (i = 0; i < ngroups; i++) {
struct ext4_group_info *grp = ext4_get_group_info(sb, i);
struct ext4_prealloc_space *pa;
ext4_grpblk_t start;
struct list_head *cur;
ext4_lock_group(sb, i);
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space,
pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
NULL, &start);
spin_unlock(&pa->pa_lock);
printk(KERN_ERR "PA:%u:%d:%u \n", i,
start, pa->pa_len);
}
ext4_unlock_group(sb, i);
if (grp->bb_free == 0)
continue;
printk(KERN_ERR "%u: %d/%d \n",
i, grp->bb_free, grp->bb_fragments);
}
printk(KERN_ERR "\n");
}
#else
static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
return;
}
#endif
/*
* We use locality group preallocation for small size file. The size of the
* file is determined by the current size or the resulting size after
* allocation which ever is larger
*
* One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
*/
static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int bsbits = ac->ac_sb->s_blocksize_bits;
loff_t size, isize;
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
>> bsbits;
if ((size == isize) &&
!ext4_fs_is_busy(sbi) &&
(atomic_read(&ac->ac_inode->i_writecount) == 0)) {
ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
return;
}
/* don't use group allocation for large files */
size = max(size, isize);
if (size >= sbi->s_mb_stream_request) {
ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
return;
}
BUG_ON(ac->ac_lg != NULL);
/*
* locality group prealloc space are per cpu. The reason for having
* per cpu locality group is to reduce the contention between block
* request from multiple CPUs.
*/
ac->ac_lg = per_cpu_ptr(sbi->s_locality_groups, raw_smp_processor_id());
/* we're going to use group allocation */
ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
/* serialize all allocations in the group */
mutex_lock(&ac->ac_lg->lg_mutex);
}
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct super_block *sb = ar->inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_group_t group;
unsigned int len;
ext4_fsblk_t goal;
ext4_grpblk_t block;
/* we can't allocate > group size */
len = ar->len;
/* just a dirty hack to filter too big requests */
if (len >= EXT4_BLOCKS_PER_GROUP(sb) - 10)
len = EXT4_BLOCKS_PER_GROUP(sb) - 10;
/* start searching from the goal */
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ext4_get_group_no_and_offset(sb, goal, &group, &block);
/* set up allocation goals */
memset(ac, 0, sizeof(struct ext4_allocation_context));
ac->ac_b_ex.fe_logical = ar->logical;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_sb = sb;
ac->ac_inode = ar->inode;
ac->ac_o_ex.fe_logical = ar->logical;
ac->ac_o_ex.fe_group = group;
ac->ac_o_ex.fe_start = block;
ac->ac_o_ex.fe_len = len;
ac->ac_g_ex.fe_logical = ar->logical;
ac->ac_g_ex.fe_group = group;
ac->ac_g_ex.fe_start = block;
ac->ac_g_ex.fe_len = len;
ac->ac_flags = ar->flags;
/* we have to define context: we'll we work with a file or
* locality group. this is a policy, actually */
ext4_mb_group_or_file(ac);
mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
"left: %u/%u, right %u/%u to %swritable\n",
(unsigned) ar->len, (unsigned) ar->logical,
(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
(unsigned) ar->lleft, (unsigned) ar->pleft,
(unsigned) ar->lright, (unsigned) ar->pright,
atomic_read(&ar->inode->i_writecount) ? "" : "non-");
return 0;
}
static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_locality_group *lg,
int order, int total_entries)
{
ext4_group_t group = 0;
struct ext4_buddy e4b;
struct list_head discard_list;
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;
mb_debug(1, "discard locality group preallocation\n");
INIT_LIST_HEAD(&discard_list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac)
ac->ac_sb = sb;
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
pa_inode_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/*
* This is the pa that we just used
* for block allocation. So don't
* free that
*/
spin_unlock(&pa->pa_lock);
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* only lg prealloc space */
BUG_ON(pa->pa_type != MB_GROUP_PA);
/* seems this one can be freed ... */
pa->pa_deleted = 1;
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &discard_list);
total_entries--;
if (total_entries <= 5) {
/*
* we want to keep only 5 entries
* allowing it to grow to 8. This
* mak sure we don't call discard
* soon for this list.
*/
break;
}
}
spin_unlock(&lg->lg_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
if (ext4_mb_load_buddy(sb, group, &e4b)) {
ext4_error(sb, __func__, "Error in loading buddy "
"information for %u", group);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_group_pa(&e4b, pa, ac);
ext4_unlock_group(sb, group);
ext4_mb_release_desc(&e4b);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
}
/*
* We have incremented pa_count. So it cannot be freed at this
* point. Also we hold lg_mutex. So no parallel allocation is
* possible from this lg. That means pa_free cannot be updated.
*
* A parallel ext4_mb_discard_group_preallocations is possible.
* which can cause the lg_prealloc_list to be updated.
*/
static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
int order, added = 0, lg_prealloc_count = 1;
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
order = fls(pa->pa_free) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
/* Add the prealloc space to lg */
rcu_read_lock();
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
pa_inode_list) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted) {
spin_unlock(&tmp_pa->pa_lock);
continue;
}
if (!added && pa->pa_free < tmp_pa->pa_free) {
/* Add to the tail of the previous entry */
list_add_tail_rcu(&pa->pa_inode_list,
&tmp_pa->pa_inode_list);
added = 1;
/*
* we want to count the total
* number of entries in the list
*/
}
spin_unlock(&tmp_pa->pa_lock);
lg_prealloc_count++;
}
if (!added)
list_add_tail_rcu(&pa->pa_inode_list,
&lg->lg_prealloc_list[order]);
rcu_read_unlock();
/* Now trim the list to be not more than 8 elements */
if (lg_prealloc_count > 8) {
ext4_mb_discard_lg_preallocations(sb, lg,
order, lg_prealloc_count);
return;
}
return ;
}
/*
* release all resource we used in allocation
*/
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
if (pa) {
if (pa->pa_type == MB_GROUP_PA) {
/* see comment in ext4_mb_use_group_pa() */
spin_lock(&pa->pa_lock);
pa->pa_pstart += ac->ac_b_ex.fe_len;
pa->pa_lstart += ac->ac_b_ex.fe_len;
pa->pa_free -= ac->ac_b_ex.fe_len;
pa->pa_len -= ac->ac_b_ex.fe_len;
spin_unlock(&pa->pa_lock);
}
}
if (ac->alloc_semp)
up_read(ac->alloc_semp);
if (pa) {
/*
* We want to add the pa to the right bucket.
* Remove it from the list and while adding
* make sure the list to which we are adding
* doesn't grow big. We need to release
* alloc_semp before calling ext4_mb_add_n_trim()
*/
if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
ext4_mb_add_n_trim(ac);
}
ext4_mb_put_pa(ac, ac->ac_sb, pa);
}
if (ac->ac_bitmap_page)
page_cache_release(ac->ac_bitmap_page);
if (ac->ac_buddy_page)
page_cache_release(ac->ac_buddy_page);
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
mutex_unlock(&ac->ac_lg->lg_mutex);
ext4_mb_collect_stats(ac);
return 0;
}
static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
{
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
int ret;
int freed = 0;
trace_ext4_mb_discard_preallocations(sb, needed);
for (i = 0; i < ngroups && needed > 0; i++) {
ret = ext4_mb_discard_group_preallocations(sb, i, needed);
freed += ret;
needed -= ret;
}
return freed;
}
/*
* Main entry point into mballoc to allocate blocks
* it tries to use preallocation first, then falls back
* to usual allocation
*/
ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
struct ext4_allocation_request *ar, int *errp)
{
int freed;
struct ext4_allocation_context *ac = NULL;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block = 0;
unsigned int inquota = 0;
unsigned int reserv_blks = 0;
sb = ar->inode->i_sb;
sbi = EXT4_SB(sb);
trace_ext4_request_blocks(ar);
/*
* For delayed allocation, we could skip the ENOSPC and
* EDQUOT check, as blocks and quotas have been already
* reserved when data being copied into pagecache.
*/
if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
ar->flags |= EXT4_MB_DELALLOC_RESERVED;
else {
/* Without delayed allocation we need to verify
* there is enough free blocks to do block allocation
* and verify allocation doesn't exceed the quota limits.
*/
while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
/* let others to free the space */
yield();
ar->len = ar->len >> 1;
}
if (!ar->len) {
*errp = -ENOSPC;
return 0;
}
reserv_blks = ar->len;
while (ar->len && vfs_dq_alloc_block(ar->inode, ar->len)) {
ar->flags |= EXT4_MB_HINT_NOPREALLOC;
ar->len--;
}
inquota = ar->len;
if (ar->len == 0) {
*errp = -EDQUOT;
goto out3;
}
}
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (!ac) {
ar->len = 0;
*errp = -ENOMEM;
goto out1;
}
*errp = ext4_mb_initialize_context(ac, ar);
if (*errp) {
ar->len = 0;
goto out2;
}
ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
if (!ext4_mb_use_preallocated(ac)) {
ac->ac_op = EXT4_MB_HISTORY_ALLOC;
ext4_mb_normalize_request(ac, ar);
repeat:
/* allocate space in core */
ext4_mb_regular_allocator(ac);
/* as we've just preallocated more space than
* user requested orinally, we store allocated
* space in a special descriptor */
if (ac->ac_status == AC_STATUS_FOUND &&
ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
ext4_mb_new_preallocation(ac);
}
if (likely(ac->ac_status == AC_STATUS_FOUND)) {
*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
if (*errp == -EAGAIN) {
/*
* drop the reference that we took
* in ext4_mb_use_best_found
*/
ext4_mb_release_context(ac);
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
goto repeat;
} else if (*errp) {
ext4_discard_allocated_blocks(ac);
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
} else {
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
ar->len = ac->ac_b_ex.fe_len;
}
} else {
freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
if (freed)
goto repeat;
*errp = -ENOSPC;
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
}
ext4_mb_release_context(ac);
out2:
kmem_cache_free(ext4_ac_cachep, ac);
out1:
if (inquota && ar->len < inquota)
vfs_dq_free_block(ar->inode, inquota - ar->len);
out3:
if (!ar->len) {
if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag)
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyblocks_counter,
reserv_blks);
}
trace_ext4_allocate_blocks(ar, (unsigned long long)block);
return block;
}
/*
* We can merge two free data extents only if the physical blocks
* are contiguous, AND the extents were freed by the same transaction,
* AND the blocks are associated with the same group.
*/
static int can_merge(struct ext4_free_data *entry1,
struct ext4_free_data *entry2)
{
if ((entry1->t_tid == entry2->t_tid) &&
(entry1->group == entry2->group) &&
((entry1->start_blk + entry1->count) == entry2->start_blk))
return 1;
return 0;
}
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
struct ext4_free_data *new_entry)
{
ext4_grpblk_t block;
struct ext4_free_data *entry;
struct ext4_group_info *db = e4b->bd_info;
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct rb_node **n = &db->bb_free_root.rb_node, *node;
struct rb_node *parent = NULL, *new_node;
BUG_ON(!ext4_handle_valid(handle));
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
new_node = &new_entry->node;
block = new_entry->start_blk;
if (!*n) {
/* first free block exent. We need to
protect buddy cache from being freed,
* otherwise we'll refresh it from
* on-disk bitmap and lose not-yet-available
* blocks */
page_cache_get(e4b->bd_buddy_page);
page_cache_get(e4b->bd_bitmap_page);
}
while (*n) {
parent = *n;
entry = rb_entry(parent, struct ext4_free_data, node);
if (block < entry->start_blk)
n = &(*n)->rb_left;
else if (block >= (entry->start_blk + entry->count))
n = &(*n)->rb_right;
else {
ext4_grp_locked_error(sb, e4b->bd_group, __func__,
"Double free of blocks %d (%d %d)",
block, entry->start_blk, entry->count);
return 0;
}
}
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);
/* Now try to see the extent can be merged to left and right */
node = rb_prev(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, node);
if (can_merge(entry, new_entry)) {
new_entry->start_blk = entry->start_blk;
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
spin_unlock(&sbi->s_md_lock);
kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
node = rb_next(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, node);
if (can_merge(new_entry, entry)) {
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
spin_unlock(&sbi->s_md_lock);
kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
/* Add the extent to transaction's private list */
spin_lock(&sbi->s_md_lock);
list_add(&new_entry->list, &handle->h_transaction->t_private_list);
spin_unlock(&sbi->s_md_lock);
return 0;
}
/**
* ext4_free_blocks() -- Free given blocks and update quota
* @handle: handle for this transaction
* @inode: inode
* @block: start physical block to free
* @count: number of blocks to count
* @metadata: Are these metadata blocks
*/
void ext4_free_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t block,
unsigned long count, int flags)
{
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_allocation_context *ac = NULL;
struct ext4_group_desc *gdp;
struct ext4_super_block *es;
unsigned long freed = 0;
unsigned int overflow;
ext4_grpblk_t bit;
struct buffer_head *gd_bh;
ext4_group_t block_group;
struct ext4_sb_info *sbi;
struct ext4_buddy e4b;
int err = 0;
int ret;
if (bh) {
if (block)
BUG_ON(block != bh->b_blocknr);
else
block = bh->b_blocknr;
}
sbi = EXT4_SB(sb);
es = EXT4_SB(sb)->s_es;
if (!ext4_data_block_valid(sbi, block, count)) {
ext4_error(sb, __func__,
"Freeing blocks not in datazone - "
"block = %llu, count = %lu", block, count);
goto error_return;
}
ext4_debug("freeing block %llu\n", block);
trace_ext4_free_blocks(inode, block, count, flags);
if (flags & EXT4_FREE_BLOCKS_FORGET) {
struct buffer_head *tbh = bh;
int i;
BUG_ON(bh && (count > 1));
for (i = 0; i < count; i++) {
if (!bh)
tbh = sb_find_get_block(inode->i_sb,
block + i);
ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
inode, tbh, block + i);
}
}
/*
* We need to make sure we don't reuse the freed block until
* after the transaction is committed, which we can do by
* treating the block as metadata, below. We make an
* exception if the inode is to be written in writeback mode
* since writeback mode has weak data consistency guarantees.
*/
if (!ext4_should_writeback_data(inode))
flags |= EXT4_FREE_BLOCKS_METADATA;
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
if (ac) {
ac->ac_inode = inode;
ac->ac_sb = sb;
}
do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb);
count -= overflow;
}
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (!bitmap_bh) {
err = -EIO;
goto error_return;
}
gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!gdp) {
err = -EIO;
goto error_return;
}
if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
in_range(block, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group)) {
ext4_error(sb, __func__,
"Freeing blocks in system zone - "
"Block = %llu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, bitmap_bh);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < count; i++)
BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
}
#endif
if (ac) {
ac->ac_b_ex.fe_group = block_group;
ac->ac_b_ex.fe_start = bit;
ac->ac_b_ex.fe_len = count;
trace_ext4_mballoc_free(ac);
}
err = ext4_mb_load_buddy(sb, block_group, &e4b);
if (err)
goto error_return;
if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
struct ext4_free_data *new_entry;
/*
* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed
*/
new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
new_entry->start_blk = bit;
new_entry->group = block_group;
new_entry->count = count;
new_entry->t_tid = handle->h_transaction->t_tid;
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count);
ext4_mb_free_metadata(handle, &e4b, new_entry);
} else {
/* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count);
mb_free_blocks(inode, &e4b, bit, count);
ext4_mb_return_to_preallocation(inode, &e4b, block, count);
}
ret = ext4_free_blks_count(sb, gdp) + count;
ext4_free_blks_set(sb, gdp, ret);
gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
ext4_unlock_group(sb, block_group);
percpu_counter_add(&sbi->s_freeblocks_counter, count);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
atomic_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
}
ext4_mb_release_desc(&e4b);
freed += count;
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
if (overflow && !err) {
block += count;
count = overflow;
put_bh(bitmap_bh);
goto do_more;
}
sb->s_dirt = 1;
error_return:
if (freed)
vfs_dq_free_block(inode, freed);
brelse(bitmap_bh);
ext4_std_error(sb, err);
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
return;
}