| /* |
| * linux/fs/ext4/balloc.c |
| * |
| * Copyright (C) 1992, 1993, 1994, 1995 |
| * Remy Card (card@masi.ibp.fr) |
| * Laboratoire MASI - Institut Blaise Pascal |
| * Universite Pierre et Marie Curie (Paris VI) |
| * |
| * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 |
| * Big-endian to little-endian byte-swapping/bitmaps by |
| * David S. Miller (davem@caip.rutgers.edu), 1995 |
| */ |
| |
| #include <linux/time.h> |
| #include <linux/capability.h> |
| #include <linux/fs.h> |
| #include <linux/jbd2.h> |
| #include <linux/quotaops.h> |
| #include <linux/buffer_head.h> |
| #include "ext4.h" |
| #include "ext4_jbd2.h" |
| #include "group.h" |
| |
| /* |
| * balloc.c contains the blocks allocation and deallocation routines |
| */ |
| |
| /* |
| * Calculate the block group number and offset, given a block number |
| */ |
| void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, |
| ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) |
| { |
| struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
| ext4_grpblk_t offset; |
| |
| blocknr = blocknr - le32_to_cpu(es->s_first_data_block); |
| offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)); |
| if (offsetp) |
| *offsetp = offset; |
| if (blockgrpp) |
| *blockgrpp = blocknr; |
| |
| } |
| |
| static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, |
| ext4_group_t block_group) |
| { |
| ext4_group_t actual_group; |
| ext4_get_group_no_and_offset(sb, block, &actual_group, 0); |
| if (actual_group == block_group) |
| return 1; |
| return 0; |
| } |
| |
| static int ext4_group_used_meta_blocks(struct super_block *sb, |
| ext4_group_t block_group) |
| { |
| ext4_fsblk_t tmp; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| /* block bitmap, inode bitmap, and inode table blocks */ |
| int used_blocks = sbi->s_itb_per_group + 2; |
| |
| if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { |
| struct ext4_group_desc *gdp; |
| struct buffer_head *bh; |
| |
| gdp = ext4_get_group_desc(sb, block_group, &bh); |
| if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), |
| block_group)) |
| used_blocks--; |
| |
| if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), |
| block_group)) |
| used_blocks--; |
| |
| tmp = ext4_inode_table(sb, gdp); |
| for (; tmp < ext4_inode_table(sb, gdp) + |
| sbi->s_itb_per_group; tmp++) { |
| if (!ext4_block_in_group(sb, tmp, block_group)) |
| used_blocks -= 1; |
| } |
| } |
| return used_blocks; |
| } |
| /* Initializes an uninitialized block bitmap if given, and returns the |
| * number of blocks free in the group. */ |
| unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, |
| ext4_group_t block_group, struct ext4_group_desc *gdp) |
| { |
| int bit, bit_max; |
| unsigned free_blocks, group_blocks; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| |
| if (bh) { |
| J_ASSERT_BH(bh, buffer_locked(bh)); |
| |
| /* If checksum is bad mark all blocks used to prevent allocation |
| * essentially implementing a per-group read-only flag. */ |
| if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { |
| ext4_error(sb, __func__, |
| "Checksum bad for group %lu\n", block_group); |
| gdp->bg_free_blocks_count = 0; |
| gdp->bg_free_inodes_count = 0; |
| gdp->bg_itable_unused = 0; |
| memset(bh->b_data, 0xff, sb->s_blocksize); |
| return 0; |
| } |
| memset(bh->b_data, 0, sb->s_blocksize); |
| } |
| |
| /* Check for superblock and gdt backups in this group */ |
| bit_max = ext4_bg_has_super(sb, block_group); |
| |
| if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || |
| block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * |
| sbi->s_desc_per_block) { |
| if (bit_max) { |
| bit_max += ext4_bg_num_gdb(sb, block_group); |
| bit_max += |
| le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); |
| } |
| } else { /* For META_BG_BLOCK_GROUPS */ |
| int group_rel = (block_group - |
| le32_to_cpu(sbi->s_es->s_first_meta_bg)) % |
| EXT4_DESC_PER_BLOCK(sb); |
| if (group_rel == 0 || group_rel == 1 || |
| (group_rel == EXT4_DESC_PER_BLOCK(sb) - 1)) |
| bit_max += 1; |
| } |
| |
| if (block_group == sbi->s_groups_count - 1) { |
| /* |
| * Even though mke2fs always initialize first and last group |
| * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need |
| * to make sure we calculate the right free blocks |
| */ |
| group_blocks = ext4_blocks_count(sbi->s_es) - |
| le32_to_cpu(sbi->s_es->s_first_data_block) - |
| (EXT4_BLOCKS_PER_GROUP(sb) * (sbi->s_groups_count -1)); |
| } else { |
| group_blocks = EXT4_BLOCKS_PER_GROUP(sb); |
| } |
| |
| free_blocks = group_blocks - bit_max; |
| |
| if (bh) { |
| ext4_fsblk_t start, tmp; |
| int flex_bg = 0; |
| |
| for (bit = 0; bit < bit_max; bit++) |
| ext4_set_bit(bit, bh->b_data); |
| |
| start = ext4_group_first_block_no(sb, block_group); |
| |
| if (EXT4_HAS_INCOMPAT_FEATURE(sb, |
| EXT4_FEATURE_INCOMPAT_FLEX_BG)) |
| flex_bg = 1; |
| |
| /* Set bits for block and inode bitmaps, and inode table */ |
| tmp = ext4_block_bitmap(sb, gdp); |
| if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) |
| ext4_set_bit(tmp - start, bh->b_data); |
| |
| tmp = ext4_inode_bitmap(sb, gdp); |
| if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) |
| ext4_set_bit(tmp - start, bh->b_data); |
| |
| tmp = ext4_inode_table(sb, gdp); |
| for (; tmp < ext4_inode_table(sb, gdp) + |
| sbi->s_itb_per_group; tmp++) { |
| if (!flex_bg || |
| ext4_block_in_group(sb, tmp, block_group)) |
| ext4_set_bit(tmp - start, bh->b_data); |
| } |
| /* |
| * Also if the number of blocks within the group is |
| * less than the blocksize * 8 ( which is the size |
| * of bitmap ), set rest of the block bitmap to 1 |
| */ |
| mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data); |
| } |
| return free_blocks - ext4_group_used_meta_blocks(sb, block_group); |
| } |
| |
| |
| /* |
| * The free blocks are managed by bitmaps. A file system contains several |
| * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap |
| * block for inodes, N blocks for the inode table and data blocks. |
| * |
| * The file system contains group descriptors which are located after the |
| * super block. Each descriptor contains the number of the bitmap block and |
| * the free blocks count in the block. The descriptors are loaded in memory |
| * when a file system is mounted (see ext4_fill_super). |
| */ |
| |
| |
| #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) |
| |
| /** |
| * ext4_get_group_desc() -- load group descriptor from disk |
| * @sb: super block |
| * @block_group: given block group |
| * @bh: pointer to the buffer head to store the block |
| * group descriptor |
| */ |
| struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb, |
| ext4_group_t block_group, |
| struct buffer_head ** bh) |
| { |
| unsigned long group_desc; |
| unsigned long offset; |
| struct ext4_group_desc * desc; |
| struct ext4_sb_info *sbi = EXT4_SB(sb); |
| |
| if (block_group >= sbi->s_groups_count) { |
| ext4_error (sb, "ext4_get_group_desc", |
| "block_group >= groups_count - " |
| "block_group = %lu, groups_count = %lu", |
| block_group, sbi->s_groups_count); |
| |
| return NULL; |
| } |
| smp_rmb(); |
| |
| group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
| offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); |
| if (!sbi->s_group_desc[group_desc]) { |
| ext4_error (sb, "ext4_get_group_desc", |
| "Group descriptor not loaded - " |
| "block_group = %lu, group_desc = %lu, desc = %lu", |
| block_group, group_desc, offset); |
| return NULL; |
| } |
| |
| desc = (struct ext4_group_desc *)( |
| (__u8 *)sbi->s_group_desc[group_desc]->b_data + |
| offset * EXT4_DESC_SIZE(sb)); |
| if (bh) |
| *bh = sbi->s_group_desc[group_desc]; |
| return desc; |
| } |
| |
| static int ext4_valid_block_bitmap(struct super_block *sb, |
| struct ext4_group_desc *desc, |
| unsigned int block_group, |
| struct buffer_head *bh) |
| { |
| ext4_grpblk_t offset; |
| ext4_grpblk_t next_zero_bit; |
| ext4_fsblk_t bitmap_blk; |
| ext4_fsblk_t group_first_block; |
| |
| if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { |
| /* with FLEX_BG, the inode/block bitmaps and itable |
| * blocks may not be in the group at all |
| * so the bitmap validation will be skipped for those groups |
| * or it has to also read the block group where the bitmaps |
| * are located to verify they are set. |
| */ |
| return 1; |
| } |
| group_first_block = ext4_group_first_block_no(sb, block_group); |
| |
| /* check whether block bitmap block number is set */ |
| bitmap_blk = ext4_block_bitmap(sb, desc); |
| offset = bitmap_blk - group_first_block; |
| if (!ext4_test_bit(offset, bh->b_data)) |
| /* bad block bitmap */ |
| goto err_out; |
| |
| /* check whether the inode bitmap block number is set */ |
| bitmap_blk = ext4_inode_bitmap(sb, desc); |
| offset = bitmap_blk - group_first_block; |
| if (!ext4_test_bit(offset, bh->b_data)) |
| /* bad block bitmap */ |
| goto err_out; |
| |
| /* check whether the inode table block number is set */ |
| bitmap_blk = ext4_inode_table(sb, desc); |
| offset = bitmap_blk - group_first_block; |
| next_zero_bit = ext4_find_next_zero_bit(bh->b_data, |
| offset + EXT4_SB(sb)->s_itb_per_group, |
| offset); |
| if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group) |
| /* good bitmap for inode tables */ |
| return 1; |
| |
| err_out: |
| ext4_error(sb, __func__, |
| "Invalid block bitmap - " |
| "block_group = %d, block = %llu", |
| block_group, bitmap_blk); |
| return 0; |
| } |
| /** |
| * ext4_read_block_bitmap() |
| * @sb: super block |
| * @block_group: given block group |
| * |
| * Read the bitmap for a given block_group,and validate the |
| * bits for block/inode/inode tables are set in the bitmaps |
| * |
| * Return buffer_head on success or NULL in case of failure. |
| */ |
| struct buffer_head * |
| ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) |
| { |
| struct ext4_group_desc * desc; |
| struct buffer_head * bh = NULL; |
| ext4_fsblk_t bitmap_blk; |
| |
| desc = ext4_get_group_desc(sb, block_group, NULL); |
| if (!desc) |
| return NULL; |
| bitmap_blk = ext4_block_bitmap(sb, desc); |
| bh = sb_getblk(sb, bitmap_blk); |
| if (unlikely(!bh)) { |
| ext4_error(sb, __func__, |
| "Cannot read block bitmap - " |
| "block_group = %d, block_bitmap = %llu", |
| (int)block_group, (unsigned long long)bitmap_blk); |
| return NULL; |
| } |
| if (bh_uptodate_or_lock(bh)) |
| return bh; |
| |
| if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { |
| ext4_init_block_bitmap(sb, bh, block_group, desc); |
| set_buffer_uptodate(bh); |
| unlock_buffer(bh); |
| return bh; |
| } |
| if (bh_submit_read(bh) < 0) { |
| put_bh(bh); |
| ext4_error(sb, __func__, |
| "Cannot read block bitmap - " |
| "block_group = %d, block_bitmap = %llu", |
| (int)block_group, (unsigned long long)bitmap_blk); |
| return NULL; |
| } |
| ext4_valid_block_bitmap(sb, desc, block_group, bh); |
| /* |
| * file system mounted not to panic on error, |
| * continue with corrupt bitmap |
| */ |
| return bh; |
| } |
| /* |
| * The reservation window structure operations |
| * -------------------------------------------- |
| * Operations include: |
| * dump, find, add, remove, is_empty, find_next_reservable_window, etc. |
| * |
| * We use a red-black tree to represent per-filesystem reservation |
| * windows. |
| * |
| */ |
| |
| /** |
| * __rsv_window_dump() -- Dump the filesystem block allocation reservation map |
| * @rb_root: root of per-filesystem reservation rb tree |
| * @verbose: verbose mode |
| * @fn: function which wishes to dump the reservation map |
| * |
| * If verbose is turned on, it will print the whole block reservation |
| * windows(start, end). Otherwise, it will only print out the "bad" windows, |
| * those windows that overlap with their immediate neighbors. |
| */ |
| #if 1 |
| static void __rsv_window_dump(struct rb_root *root, int verbose, |
| const char *fn) |
| { |
| struct rb_node *n; |
| struct ext4_reserve_window_node *rsv, *prev; |
| int bad; |
| |
| restart: |
| n = rb_first(root); |
| bad = 0; |
| prev = NULL; |
| |
| printk("Block Allocation Reservation Windows Map (%s):\n", fn); |
| while (n) { |
| rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
| if (verbose) |
| printk("reservation window 0x%p " |
| "start: %llu, end: %llu\n", |
| rsv, rsv->rsv_start, rsv->rsv_end); |
| if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { |
| printk("Bad reservation %p (start >= end)\n", |
| rsv); |
| bad = 1; |
| } |
| if (prev && prev->rsv_end >= rsv->rsv_start) { |
| printk("Bad reservation %p (prev->end >= start)\n", |
| rsv); |
| bad = 1; |
| } |
| if (bad) { |
| if (!verbose) { |
| printk("Restarting reservation walk in verbose mode\n"); |
| verbose = 1; |
| goto restart; |
| } |
| } |
| n = rb_next(n); |
| prev = rsv; |
| } |
| printk("Window map complete.\n"); |
| BUG_ON(bad); |
| } |
| #define rsv_window_dump(root, verbose) \ |
| __rsv_window_dump((root), (verbose), __func__) |
| #else |
| #define rsv_window_dump(root, verbose) do {} while (0) |
| #endif |
| |
| /** |
| * goal_in_my_reservation() |
| * @rsv: inode's reservation window |
| * @grp_goal: given goal block relative to the allocation block group |
| * @group: the current allocation block group |
| * @sb: filesystem super block |
| * |
| * Test if the given goal block (group relative) is within the file's |
| * own block reservation window range. |
| * |
| * If the reservation window is outside the goal allocation group, return 0; |
| * grp_goal (given goal block) could be -1, which means no specific |
| * goal block. In this case, always return 1. |
| * If the goal block is within the reservation window, return 1; |
| * otherwise, return 0; |
| */ |
| static int |
| goal_in_my_reservation(struct ext4_reserve_window *rsv, ext4_grpblk_t grp_goal, |
| ext4_group_t group, struct super_block *sb) |
| { |
| ext4_fsblk_t group_first_block, group_last_block; |
| |
| group_first_block = ext4_group_first_block_no(sb, group); |
| group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); |
| |
| if ((rsv->_rsv_start > group_last_block) || |
| (rsv->_rsv_end < group_first_block)) |
| return 0; |
| if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) |
| || (grp_goal + group_first_block > rsv->_rsv_end))) |
| return 0; |
| return 1; |
| } |
| |
| /** |
| * search_reserve_window() |
| * @rb_root: root of reservation tree |
| * @goal: target allocation block |
| * |
| * Find the reserved window which includes the goal, or the previous one |
| * if the goal is not in any window. |
| * Returns NULL if there are no windows or if all windows start after the goal. |
| */ |
| static struct ext4_reserve_window_node * |
| search_reserve_window(struct rb_root *root, ext4_fsblk_t goal) |
| { |
| struct rb_node *n = root->rb_node; |
| struct ext4_reserve_window_node *rsv; |
| |
| if (!n) |
| return NULL; |
| |
| do { |
| rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
| |
| if (goal < rsv->rsv_start) |
| n = n->rb_left; |
| else if (goal > rsv->rsv_end) |
| n = n->rb_right; |
| else |
| return rsv; |
| } while (n); |
| /* |
| * We've fallen off the end of the tree: the goal wasn't inside |
| * any particular node. OK, the previous node must be to one |
| * side of the interval containing the goal. If it's the RHS, |
| * we need to back up one. |
| */ |
| if (rsv->rsv_start > goal) { |
| n = rb_prev(&rsv->rsv_node); |
| rsv = rb_entry(n, struct ext4_reserve_window_node, rsv_node); |
| } |
| return rsv; |
| } |
| |
| /** |
| * ext4_rsv_window_add() -- Insert a window to the block reservation rb tree. |
| * @sb: super block |
| * @rsv: reservation window to add |
| * |
| * Must be called with rsv_lock hold. |
| */ |
| void ext4_rsv_window_add(struct super_block *sb, |
| struct ext4_reserve_window_node *rsv) |
| { |
| struct rb_root *root = &EXT4_SB(sb)->s_rsv_window_root; |
| struct rb_node *node = &rsv->rsv_node; |
| ext4_fsblk_t start = rsv->rsv_start; |
| |
| struct rb_node ** p = &root->rb_node; |
| struct rb_node * parent = NULL; |
| struct ext4_reserve_window_node *this; |
| |
| while (*p) |
| { |
| parent = *p; |
| this = rb_entry(parent, struct ext4_reserve_window_node, rsv_node); |
| |
| if (start < this->rsv_start) |
| p = &(*p)->rb_left; |
| else if (start > this->rsv_end) |
| p = &(*p)->rb_right; |
| else { |
| rsv_window_dump(root, 1); |
| BUG(); |
| } |
| } |
| |
| rb_link_node(node, parent, p); |
| rb_insert_color(node, root); |
| } |
| |
| /** |
| * ext4_rsv_window_remove() -- unlink a window from the reservation rb tree |
| * @sb: super block |
| * @rsv: reservation window to remove |
| * |
| * Mark the block reservation window as not allocated, and unlink it |
| * from the filesystem reservation window rb tree. Must be called with |
| * rsv_lock hold. |
| */ |
| static void rsv_window_remove(struct super_block *sb, |
| struct ext4_reserve_window_node *rsv) |
| { |
| rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
| rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
| rsv->rsv_alloc_hit = 0; |
| rb_erase(&rsv->rsv_node, &EXT4_SB(sb)->s_rsv_window_root); |
| } |
| |
| /* |
| * rsv_is_empty() -- Check if the reservation window is allocated. |
| * @rsv: given reservation window to check |
| * |
| * returns 1 if the end block is EXT4_RESERVE_WINDOW_NOT_ALLOCATED. |
| */ |
| static inline int rsv_is_empty(struct ext4_reserve_window *rsv) |
| { |
| /* a valid reservation end block could not be 0 */ |
| return rsv->_rsv_end == EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
| } |
| |
| /** |
| * ext4_init_block_alloc_info() |
| * @inode: file inode structure |
| * |
| * Allocate and initialize the reservation window structure, and |
| * link the window to the ext4 inode structure at last |
| * |
| * The reservation window structure is only dynamically allocated |
| * and linked to ext4 inode the first time the open file |
| * needs a new block. So, before every ext4_new_block(s) call, for |
| * regular files, we should check whether the reservation window |
| * structure exists or not. In the latter case, this function is called. |
| * Fail to do so will result in block reservation being turned off for that |
| * open file. |
| * |
| * This function is called from ext4_get_blocks_handle(), also called |
| * when setting the reservation window size through ioctl before the file |
| * is open for write (needs block allocation). |
| * |
| * Needs down_write(i_data_sem) protection prior to call this function. |
| */ |
| void ext4_init_block_alloc_info(struct inode *inode) |
| { |
| struct ext4_inode_info *ei = EXT4_I(inode); |
| struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; |
| struct super_block *sb = inode->i_sb; |
| |
| block_i = kmalloc(sizeof(*block_i), GFP_NOFS); |
| if (block_i) { |
| struct ext4_reserve_window_node *rsv = &block_i->rsv_window_node; |
| |
| rsv->rsv_start = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
| rsv->rsv_end = EXT4_RESERVE_WINDOW_NOT_ALLOCATED; |
| |
| /* |
| * if filesystem is mounted with NORESERVATION, the goal |
| * reservation window size is set to zero to indicate |
| * block reservation is off |
| */ |
| if (!test_opt(sb, RESERVATION)) |
| rsv->rsv_goal_size = 0; |
| else |
| rsv->rsv_goal_size = EXT4_DEFAULT_RESERVE_BLOCKS; |
| rsv->rsv_alloc_hit = 0; |
| block_i->last_alloc_logical_block = 0; |
| block_i->last_alloc_physical_block = 0; |
| } |
| ei->i_block_alloc_info = block_i; |
| } |
| |
| /** |
| * ext4_discard_reservation() |
| * @inode: inode |
| * |
| * Discard(free) block reservation window on last file close, or truncate |
| * or at last iput(). |
| * |
| * It is being called in three cases: |
| * ext4_release_file(): last writer close the file |
| * ext4_clear_inode(): last iput(), when nobody link to this file. |
| * ext4_truncate(): when the block indirect map is about to change. |
| * |
| */ |
| void ext4_discard_reservation(struct inode *inode) |
| { |
| struct ext4_inode_info *ei = EXT4_I(inode); |
| struct ext4_block_alloc_info *block_i = ei->i_block_alloc_info; |
| struct ext4_reserve_window_node *rsv; |
| spinlock_t *rsv_lock = &EXT4_SB(inode->i_sb)->s_rsv_window_lock; |
| |
| ext4_mb_discard_inode_preallocations(inode); |
| |
| if (!block_i) |
| return; |
| |
| rsv = &block_i->rsv_window_node; |
| if (!rsv_is_empty(&rsv->rsv_window)) { |
| spin_lock(rsv_lock); |
| if (!rsv_is_empty(&rsv->rsv_window)) |
| rsv_window_remove(inode->i_sb, rsv); |
| spin_unlock(rsv_lock); |
| } |
| } |
| |
| /** |
| * ext4_free_blocks_sb() -- Free given blocks and update quota |
| * @handle: handle to this transaction |
| * @sb: super block |
| * @block: start physcial block to free |
| * @count: number of blocks to free |
| * @pdquot_freed_blocks: pointer to quota |
| */ |
| void ext4_free_blocks_sb(handle_t *handle, struct super_block *sb, |
| ext4_fsblk_t block, unsigned long count, |
| unsigned long *pdquot_freed_blocks) |
| { |
| struct buffer_head *bitmap_bh = NULL; |
| struct buffer_head *gd_bh; |
| ext4_group_t block_group; |
| ext4_grpblk_t bit; |
| unsigned long i; |
| unsigned long overflow; |
| struct ext4_group_desc * desc; |
| struct ext4_super_block * es; |
| struct ext4_sb_info *sbi; |
| int err = 0, ret; |
| ext4_grpblk_t group_freed; |
| |
| *pdquot_freed_blocks = 0; |
| sbi = EXT4_SB(sb); |
| es = sbi->s_es; |
| if (block < le32_to_cpu(es->s_first_data_block) || |
| block + count < block || |
| block + count > ext4_blocks_count(es)) { |
| ext4_error (sb, "ext4_free_blocks", |
| "Freeing blocks not in datazone - " |
| "block = %llu, count = %lu", block, count); |
| goto error_return; |
| } |
| |
| ext4_debug ("freeing block(s) %llu-%llu\n", block, block + count - 1); |
| |
| 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; |
| } |
| brelse(bitmap_bh); |
| bitmap_bh = ext4_read_block_bitmap(sb, block_group); |
| if (!bitmap_bh) |
| goto error_return; |
| desc = ext4_get_group_desc (sb, block_group, &gd_bh); |
| if (!desc) |
| goto error_return; |
| |
| if (in_range(ext4_block_bitmap(sb, desc), block, count) || |
| in_range(ext4_inode_bitmap(sb, desc), block, count) || |
| in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) || |
| in_range(block + count - 1, ext4_inode_table(sb, desc), |
| sbi->s_itb_per_group)) { |
| ext4_error (sb, "ext4_free_blocks", |
| "Freeing blocks in system zones - " |
| "Block = %llu, count = %lu", |
| block, count); |
| goto error_return; |
| } |
| |
| /* |
| * We are about to start releasing blocks in the bitmap, |
| * so we need undo access. |
| */ |
| /* @@@ check errors */ |
| BUFFER_TRACE(bitmap_bh, "getting undo access"); |
| err = ext4_journal_get_undo_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; |
| |
| jbd_lock_bh_state(bitmap_bh); |
| |
| for (i = 0, group_freed = 0; i < count; i++) { |
| /* |
| * An HJ special. This is expensive... |
| */ |
| #ifdef CONFIG_JBD2_DEBUG |
| jbd_unlock_bh_state(bitmap_bh); |
| { |
| struct buffer_head *debug_bh; |
| debug_bh = sb_find_get_block(sb, block + i); |
| if (debug_bh) { |
| BUFFER_TRACE(debug_bh, "Deleted!"); |
| if (!bh2jh(bitmap_bh)->b_committed_data) |
| BUFFER_TRACE(debug_bh, |
| "No commited data in bitmap"); |
| BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap"); |
| __brelse(debug_bh); |
| } |
| } |
| jbd_lock_bh_state(bitmap_bh); |
| #endif |
| if (need_resched()) { |
| jbd_unlock_bh_state(bitmap_bh); |
| cond_resched(); |
| jbd_lock_bh_state(bitmap_bh); |
| } |
| /* @@@ This prevents newly-allocated data from being |
| * freed and then reallocated within the same |
| * transaction. |
| * |
| * Ideally we would want to allow that to happen, but to |
| * do so requires making jbd2_journal_forget() capable of |
| * revoking the queued write of a data block, which |
| * implies blocking on the journal lock. *forget() |
| * cannot block due to truncate races. |
| * |
| * Eventually we can fix this by making jbd2_journal_forget() |
| * return a status indicating whether or not it was able |
| * to revoke the buffer. On successful revoke, it is |
| * safe not to set the allocation bit in the committed |
| * bitmap, because we know that there is no outstanding |
| * activity on the buffer any more and so it is safe to |
| * reallocate it. |
| */ |
| BUFFER_TRACE(bitmap_bh, "set in b_committed_data"); |
| J_ASSERT_BH(bitmap_bh, |
| bh2jh(bitmap_bh)->b_committed_data != NULL); |
| ext4_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i, |
| bh2jh(bitmap_bh)->b_committed_data); |
| |
| /* |
| * We clear the bit in the bitmap after setting the committed |
| * data bit, because this is the reverse order to that which |
| * the allocator uses. |
| */ |
| BUFFER_TRACE(bitmap_bh, "clear bit"); |
| if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group), |
| bit + i, bitmap_bh->b_data)) { |
| jbd_unlock_bh_state(bitmap_bh); |
| ext4_error(sb, __func__, |
| "bit already cleared for block %llu", |
| (ext4_fsblk_t)(block + i)); |
| jbd_lock_bh_state(bitmap_bh); |
| BUFFER_TRACE(bitmap_bh, "bit already cleared"); |
| } else { |
| group_freed++; |
| } |
| } |
| jbd_unlock_bh_state(bitmap_bh); |
| |
| spin_lock(sb_bgl_lock(sbi, block_group)); |
| le16_add_cpu(&desc->bg_free_blocks_count, group_freed); |
| desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc); |
| spin_unlock(sb_bgl_lock(sbi, 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); |
| spin_lock(sb_bgl_lock(sbi, flex_group)); |
| sbi->s_flex_groups[flex_group].free_blocks += count; |
| spin_unlock(sb_bgl_lock(sbi, flex_group)); |
| } |
| |
| /* We dirtied the bitmap block */ |
| BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); |
| err = ext4_journal_dirty_metadata(handle, bitmap_bh); |
| |
| /* And the group descriptor block */ |
| BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); |
| ret = ext4_journal_dirty_metadata(handle, gd_bh); |
| if (!err) err = ret; |
| *pdquot_freed_blocks += group_freed; |
| |
| if (overflow && !err) { |
| block += count; |
| count = overflow; |
| goto do_more; |
| } |
| sb->s_dirt = 1; |
| error_return: |
| brelse(bitmap_bh); |
| ext4_std_error(sb, err); |
| return; |
| } |
| |
| /** |
| * 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, |
| ext4_fsblk_t block, unsigned long count, |
| int metadata) |
| { |
| struct super_block * sb; |
| unsigned long dquot_freed_blocks; |
| |
| /* this isn't the right place to decide whether block is metadata |
| * inode.c/extents.c knows better, but for safety ... */ |
| if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) || |
| ext4_should_journal_data(inode)) |
| metadata = 1; |
| |
| sb = inode->i_sb; |
| |
| if (!test_opt(sb, MBALLOC) || !EXT4_SB(sb)->s_group_info) |
| ext4_free_blocks_sb(handle, sb, block, count, |
| &dquot_freed_blocks); |
| else |
| ext4_mb_free_blocks(handle, inode, block, count, |
| metadata, &dquot_freed_blocks); |
| if (dquot_freed_blocks) |
| DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); |
| return; |
| } |
| |
| /** |
| * ext4_test_allocatable() |
| * @nr: given allocation block group |
| * @bh: bufferhead contains the bitmap of the given block group |
| * |
| * For ext4 allocations, we must not reuse any blocks which are |
| * allocated in the bitmap buffer's "last committed data" copy. This |
| * prevents deletes from freeing up the page for reuse until we have |
| * committed the delete transaction. |
| * |
| * If we didn't do this, then deleting something and reallocating it as |
| * data would allow the old block to be overwritten before the |
| * transaction committed (because we force data to disk before commit). |
| * This would lead to corruption if we crashed between overwriting the |
| * data and committing the delete. |
| * |
| * @@@ We may want to make this allocation behaviour conditional on |
| * data-writes at some point, and disable it for metadata allocations or |
| * sync-data inodes. |
| */ |
| static int ext4_test_allocatable(ext4_grpblk_t nr, struct buffer_head *bh) |
| { |
| int ret; |
| struct journal_head *jh = bh2jh(bh); |
| |
| if (ext4_test_bit(nr, bh->b_data)) |
| return 0; |
| |
| jbd_lock_bh_state(bh); |
| if (!jh->b_committed_data) |
| ret = 1; |
| else |
| ret = !ext4_test_bit(nr, jh->b_committed_data); |
| jbd_unlock_bh_state(bh); |
| return ret; |
| } |
| |
| /** |
| * bitmap_search_next_usable_block() |
| * @start: the starting block (group relative) of the search |
| * @bh: bufferhead contains the block group bitmap |
| * @maxblocks: the ending block (group relative) of the reservation |
| * |
| * The bitmap search --- search forward alternately through the actual |
| * bitmap on disk and the last-committed copy in journal, until we find a |
| * bit free in both bitmaps. |
| */ |
| static ext4_grpblk_t |
| bitmap_search_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, |
| ext4_grpblk_t maxblocks) |
| { |
| ext4_grpblk_t next; |
| struct journal_head *jh = bh2jh(bh); |
| |
| while (start < maxblocks) { |
| next = ext4_find_next_zero_bit(bh->b_data, maxblocks, start); |
| if (next >= maxblocks) |
| return -1; |
| if (ext4_test_allocatable(next, bh)) |
| return next; |
| jbd_lock_bh_state(bh); |
| if (jh->b_committed_data) |
| start = ext4_find_next_zero_bit(jh->b_committed_data, |
| maxblocks, next); |
| jbd_unlock_bh_state(bh); |
| } |
| return -1; |
| } |
| |
| /** |
| * find_next_usable_block() |
| * @start: the starting block (group relative) to find next |
| * allocatable block in bitmap. |
| * @bh: bufferhead contains the block group bitmap |
| * @maxblocks: the ending block (group relative) for the search |
| * |
| * Find an allocatable block in a bitmap. We honor both the bitmap and |
| * its last-committed copy (if that exists), and perform the "most |
| * appropriate allocation" algorithm of looking for a free block near |
| * the initial goal; then for a free byte somewhere in the bitmap; then |
| * for any free bit in the bitmap. |
| */ |
| static ext4_grpblk_t |
| find_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh, |
| ext4_grpblk_t maxblocks) |
| { |
| ext4_grpblk_t here, next; |
| char *p, *r; |
| |
| if (start > 0) { |
| /* |
| * The goal was occupied; search forward for a free |
| * block within the next XX blocks. |
| * |
| * end_goal is more or less random, but it has to be |
| * less than EXT4_BLOCKS_PER_GROUP. Aligning up to the |
| * next 64-bit boundary is simple.. |
| */ |
| ext4_grpblk_t end_goal = (start + 63) & ~63; |
| if (end_goal > maxblocks) |
| end_goal = maxblocks; |
| here = ext4_find_next_zero_bit(bh->b_data, end_goal, start); |
| if (here < end_goal && ext4_test_allocatable(here, bh)) |
| return here; |
| ext4_debug("Bit not found near goal\n"); |
| } |
| |
| here = start; |
| if (here < 0) |
| here = 0; |
| |
| p = ((char *)bh->b_data) + (here >> 3); |
| r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3)); |
| next = (r - ((char *)bh->b_data)) << 3; |
| |
| if (next < maxblocks && next >= start && ext4_test_allocatable(next, bh)) |
| return next; |
| |
| /* |
| * The bitmap search --- search forward alternately through the actual |
| * bitmap and the last-committed copy until we find a bit free in |
| * both |
| */ |
| here = bitmap_search_next_usable_block(here, bh, maxblocks); |
| return here; |
| } |
| |
| /** |
| * claim_block() |
| * @block: the free block (group relative) to allocate |
| * @bh: the bufferhead containts the block group bitmap |
| * |
| * We think we can allocate this block in this bitmap. Try to set the bit. |
| * If that succeeds then check that nobody has allocated and then freed the |
| * block since we saw that is was not marked in b_committed_data. If it _was_ |
| * allocated and freed then clear the bit in the bitmap again and return |
| * zero (failure). |
| */ |
| static inline int |
| claim_block(spinlock_t *lock, ext4_grpblk_t block, struct buffer_head *bh) |
| { |
| struct journal_head *jh = bh2jh(bh); |
| int ret; |
| |
| if (ext4_set_bit_atomic(lock, block, bh->b_data)) |
| return 0; |
| jbd_lock_bh_state(bh); |
| if (jh->b_committed_data && ext4_test_bit(block,jh->b_committed_data)) { |
| ext4_clear_bit_atomic(lock, block, bh->b_data); |
| ret = 0; |
| } else { |
| ret = 1; |
| } |
| jbd_unlock_bh_state(bh); |
| return ret; |
| } |
| |
| /** |
| * ext4_try_to_allocate() |
| * @sb: superblock |
| * @handle: handle to this transaction |
| * @group: given allocation block group |
| * @bitmap_bh: bufferhead holds the block bitmap |
| * @grp_goal: given target block within the group |
| * @count: target number of blocks to allocate |
| * @my_rsv: reservation window |
| * |
| * Attempt to allocate blocks within a give range. Set the range of allocation |
| * first, then find the first free bit(s) from the bitmap (within the range), |
| * and at last, allocate the blocks by claiming the found free bit as allocated. |
| * |
| * To set the range of this allocation: |
| * if there is a reservation window, only try to allocate block(s) from the |
| * file's own reservation window; |
| * Otherwise, the allocation range starts from the give goal block, ends at |
| * the block group's last block. |
| * |
| * If we failed to allocate the desired block then we may end up crossing to a |
| * new bitmap. In that case we must release write access to the old one via |
| * ext4_journal_release_buffer(), else we'll run out of credits. |
| */ |
| static ext4_grpblk_t |
| ext4_try_to_allocate(struct super_block *sb, handle_t *handle, |
| ext4_group_t group, struct buffer_head *bitmap_bh, |
| ext4_grpblk_t grp_goal, unsigned long *count, |
| struct ext4_reserve_window *my_rsv) |
| { |
| ext4_fsblk_t group_first_block; |
| ext4_grpblk_t start, end; |
| unsigned long num = 0; |
| |
| /* we do allocation within the reservation window if we have a window */ |
| if (my_rsv) { |
| group_first_block = ext4_group_first_block_no(sb, group); |
| if (my_rsv->_rsv_start >= group_first_block) |
| start = my_rsv->_rsv_start - group_first_block; |
| else |
| /* reservation window cross group boundary */ |
| start = 0; |
| end = my_rsv->_rsv_end - group_first_block + 1; |
| if (end > EXT4_BLOCKS_PER_GROUP(sb)) |
| /* reservation window crosses group boundary */ |
| end = EXT4_BLOCKS_PER_GROUP(sb); |
| if ((start <= grp_goal) && (grp_goal < end)) |
| start = grp_goal; |
| else |
| grp_goal = -1; |
| } else { |
| if (grp_goal > 0) |
| start = grp_goal; |
| else |
| start = 0; |
| end = EXT4_BLOCKS_PER_GROUP(sb); |
| } |
| |
| BUG_ON(start > EXT4_BLOCKS_PER_GROUP(sb)); |
| |
| repeat: |
| if (grp_goal < 0 || !ext4_test_allocatable(grp_goal, bitmap_bh)) { |
| grp_goal = find_next_usable_block(start, bitmap_bh, end); |
| if (grp_goal < 0) |
| goto fail_access; |
| if (!my_rsv) { |
| int i; |
| |
| for (i = 0; i < 7 && grp_goal > start && |
| ext4_test_allocatable(grp_goal - 1, |
| bitmap_bh); |
| i++, grp_goal--) |
| ; |
| } |
| } |
| start = grp_goal; |
| |
| if (!claim_block(sb_bgl_lock(EXT4_SB(sb), group), |
| grp_goal, bitmap_bh)) { |
| /* |
| * The block was allocated by another thread, or it was |
| * allocated and then freed by another thread |
| */ |
| start++; |
| grp_goal++; |
| if (start >= end) |
| goto fail_access; |
| goto repeat; |
| } |
| num++; |
| grp_goal++; |
| while (num < *count && grp_goal < end |
| && ext4_test_allocatable(grp_goal, bitmap_bh) |
| && claim_block(sb_bgl_lock(EXT4_SB(sb), group), |
| grp_goal, bitmap_bh)) { |
| num++; |
| grp_goal++; |
| } |
| *count = num; |
| return grp_goal - num; |
| fail_access: |
| *count = num; |
| return -1; |
| } |
| |
| /** |
| * find_next_reservable_window(): |
| * find a reservable space within the given range. |
| * It does not allocate the reservation window for now: |
| * alloc_new_reservation() will do the work later. |
| * |
| * @search_head: the head of the searching list; |
| * This is not necessarily the list head of the whole filesystem |
| * |
| * We have both head and start_block to assist the search |
| * for the reservable space. The list starts from head, |
| * but we will shift to the place where start_block is, |
| * then start from there, when looking for a reservable space. |
| * |
| * @size: the target new reservation window size |
| * |
| * @group_first_block: the first block we consider to start |
| * the real search from |
| * |
| * @last_block: |
| * the maximum block number that our goal reservable space |
| * could start from. This is normally the last block in this |
| * group. The search will end when we found the start of next |
| * possible reservable space is out of this boundary. |
| * This could handle the cross boundary reservation window |
| * request. |
| * |
| * basically we search from the given range, rather than the whole |
| * reservation double linked list, (start_block, last_block) |
| * to find a free region that is of my size and has not |
| * been reserved. |
| * |
| */ |
| static int find_next_reservable_window( |
| struct ext4_reserve_window_node *search_head, |
| struct ext4_reserve_window_node *my_rsv, |
| struct super_block * sb, |
| ext4_fsblk_t start_block, |
| ext4_fsblk_t last_block) |
| { |
| struct rb_node *next; |
| struct ext4_reserve_window_node *rsv, *prev; |
| ext4_fsblk_t cur; |
| int size = my_rsv->rsv_goal_size; |
| |
| /* TODO: make the start of the reservation window byte-aligned */ |
| /* cur = *start_block & ~7;*/ |
| cur = start_block; |
| rsv = search_head; |
| if (!rsv) |
| return -1; |
| |
| while (1) { |
| if (cur <= rsv->rsv_end) |
| cur = rsv->rsv_end + 1; |
| |
| /* TODO? |
| * in the case we could not find a reservable space |
| * that is what is expected, during the re-search, we could |
| * remember what's the largest reservable space we could have |
| * and return that one. |
| * |
| * For now it will fail if we could not find the reservable |
| * space with expected-size (or more)... |
| */ |
| if (cur > last_block) |
| return -1; /* fail */ |
| |
| prev = rsv; |
| next = rb_next(&rsv->rsv_node); |
| rsv = rb_entry(next,struct ext4_reserve_window_node,rsv_node); |
| |
| /* |
| * Reached the last reservation, we can just append to the |
| * previous one. |
| */ |
| if (!next) |
| break; |
| |
| if (cur + size <= rsv->rsv_start) { |
| /* |
| * Found a reserveable space big enough. We could |
| * have a reservation across the group boundary here |
| */ |
| break; |
| } |
| } |
| /* |
| * we come here either : |
| * when we reach the end of the whole list, |
| * and there is empty reservable space after last entry in the list. |
| * append it to the end of the list. |
| * |
| * or we found one reservable space in the middle of the list, |
| * return the reservation window that we could append to. |
| * succeed. |
| */ |
| |
| if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) |
| rsv_window_remove(sb, my_rsv); |
| |
| /* |
| * Let's book the whole avaliable window for now. We will check the |
| * disk bitmap later and then, if there are free blocks then we adjust |
| * the window size if it's larger than requested. |
| * Otherwise, we will remove this node from the tree next time |
| * call find_next_reservable_window. |
| */ |
| my_rsv->rsv_start = cur; |
| my_rsv->rsv_end = cur + size - 1; |
| my_rsv->rsv_alloc_hit = 0; |
| |
| if (prev != my_rsv) |
| ext4_rsv_window_add(sb, my_rsv); |
| |
| return 0; |
| } |
| |
| /** |
| * alloc_new_reservation()--allocate a new reservation window |
| * |
| * To make a new reservation, we search part of the filesystem |
| * reservation list (the list that inside the group). We try to |
| * allocate a new reservation window near the allocation goal, |
| * or the beginning of the group, if there is no goal. |
| * |
| * We first find a reservable space after the goal, then from |
| * there, we check the bitmap for the first free block after |
| * it. If there is no free block until the end of group, then the |
| * whole group is full, we failed. Otherwise, check if the free |
| * block is inside the expected reservable space, if so, we |
| * succeed. |
| * If the first free block is outside the reservable space, then |
| * start from the first free block, we search for next available |
| * space, and go on. |
| * |
| * on succeed, a new reservation will be found and inserted into the list |
| * It contains at least one free block, and it does not overlap with other |
| * reservation windows. |
| * |
| * failed: we failed to find a reservation window in this group |
| * |
| * @rsv: the reservation |
| * |
| * @grp_goal: The goal (group-relative). It is where the search for a |
| * free reservable space should start from. |
| * if we have a grp_goal(grp_goal >0 ), then start from there, |
| * no grp_goal(grp_goal = -1), we start from the first block |
| * of the group. |
| * |
| * @sb: the super block |
| * @group: the group we are trying to allocate in |
| * @bitmap_bh: the block group block bitmap |
| * |
| */ |
| static int alloc_new_reservation(struct ext4_reserve_window_node *my_rsv, |
| ext4_grpblk_t grp_goal, struct super_block *sb, |
| ext4_group_t group, struct buffer_head *bitmap_bh) |
| { |
| struct ext4_reserve_window_node *search_head; |
| ext4_fsblk_t group_first_block, group_end_block, start_block; |
| ext4_grpblk_t first_free_block; |
| struct rb_root *fs_rsv_root = &EXT4_SB(sb)->s_rsv_window_root; |
| unsigned long size; |
| int ret; |
| spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
| |
| group_first_block = ext4_group_first_block_no(sb, group); |
| group_end_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); |
| |
| if (grp_goal < 0) |
| start_block = group_first_block; |
| else |
| start_block = grp_goal + group_first_block; |
| |
| size = my_rsv->rsv_goal_size; |
| |
| if (!rsv_is_empty(&my_rsv->rsv_window)) { |
| /* |
| * if the old reservation is cross group boundary |
| * and if the goal is inside the old reservation window, |
| * we will come here when we just failed to allocate from |
| * the first part of the window. We still have another part |
| * that belongs to the next group. In this case, there is no |
| * point to discard our window and try to allocate a new one |
| * in this group(which will fail). we should |
| * keep the reservation window, just simply move on. |
| * |
| * Maybe we could shift the start block of the reservation |
| * window to the first block of next group. |
| */ |
| |
| if ((my_rsv->rsv_start <= group_end_block) && |
| (my_rsv->rsv_end > group_end_block) && |
| (start_block >= my_rsv->rsv_start)) |
| return -1; |
| |
| if ((my_rsv->rsv_alloc_hit > |
| (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { |
| /* |
| * if the previously allocation hit ratio is |
| * greater than 1/2, then we double the size of |
| * the reservation window the next time, |
| * otherwise we keep the same size window |
| */ |
| size = size * 2; |
| if (size > EXT4_MAX_RESERVE_BLOCKS) |
| size = EXT4_MAX_RESERVE_BLOCKS; |
| my_rsv->rsv_goal_size= size; |
| } |
| } |
| |
| spin_lock(rsv_lock); |
| /* |
| * shift the search start to the window near the goal block |
| */ |
| search_head = search_reserve_window(fs_rsv_root, start_block); |
| |
| /* |
| * find_next_reservable_window() simply finds a reservable window |
| * inside the given range(start_block, group_end_block). |
| * |
| * To make sure the reservation window has a free bit inside it, we |
| * need to check the bitmap after we found a reservable window. |
| */ |
| retry: |
| ret = find_next_reservable_window(search_head, my_rsv, sb, |
| start_block, group_end_block); |
| |
| if (ret == -1) { |
| if (!rsv_is_empty(&my_rsv->rsv_window)) |
| rsv_window_remove(sb, my_rsv); |
| spin_unlock(rsv_lock); |
| return -1; |
| } |
| |
| /* |
| * On success, find_next_reservable_window() returns the |
| * reservation window where there is a reservable space after it. |
| * Before we reserve this reservable space, we need |
| * to make sure there is at least a free block inside this region. |
| * |
| * searching the first free bit on the block bitmap and copy of |
| * last committed bitmap alternatively, until we found a allocatable |
| * block. Search start from the start block of the reservable space |
| * we just found. |
| */ |
| spin_unlock(rsv_lock); |
| first_free_block = bitmap_search_next_usable_block( |
| my_rsv->rsv_start - group_first_block, |
| bitmap_bh, group_end_block - group_first_block + 1); |
| |
| if (first_free_block < 0) { |
| /* |
| * no free block left on the bitmap, no point |
| * to reserve the space. return failed. |
| */ |
| spin_lock(rsv_lock); |
| if (!rsv_is_empty(&my_rsv->rsv_window)) |
| rsv_window_remove(sb, my_rsv); |
| spin_unlock(rsv_lock); |
| return -1; /* failed */ |
| } |
| |
| start_block = first_free_block + group_first_block; |
| /* |
| * check if the first free block is within the |
| * free space we just reserved |
| */ |
| if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end) |
| return 0; /* success */ |
| /* |
| * if the first free bit we found is out of the reservable space |
| * continue search for next reservable space, |
| * start from where the free block is, |
| * we also shift the list head to where we stopped last time |
| */ |
| search_head = my_rsv; |
| spin_lock(rsv_lock); |
| goto retry; |
| } |
| |
| /** |
| * try_to_extend_reservation() |
| * @my_rsv: given reservation window |
| * @sb: super block |
| * @size: the delta to extend |
| * |
| * Attempt to expand the reservation window large enough to have |
| * required number of free blocks |
| * |
| * Since ext4_try_to_allocate() will always allocate blocks within |
| * the reservation window range, if the window size is too small, |
| * multiple blocks allocation has to stop at the end of the reservation |
| * window. To make this more efficient, given the total number of |
| * blocks needed and the current size of the window, we try to |
| * expand the reservation window size if necessary on a best-effort |
| * basis before ext4_new_blocks() tries to allocate blocks, |
| */ |
| static void try_to_extend_reservation(struct ext4_reserve_window_node *my_rsv, |
| struct super_block *sb, int size) |
| { |
| struct ext4_reserve_window_node *next_rsv; |
| struct rb_node *next; |
| spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock; |
| |
| if (!spin_trylock(rsv_lock)) |
| return; |
| |
| next = rb_next(&my_rsv->rsv_node); |
| |
| if (!next) |
| my_rsv->rsv_end += size; |
| else { |
| next_rsv = rb_entry(next, struct ext4_reserve_window_node, rsv_node); |
| |
| if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) |
| my_rsv->rsv_end += size; |
| else |
| my_rsv->rsv_end = next_rsv->rsv_start - 1; |
| } |
| spin_unlock(rsv_lock); |
| } |
| |
| /** |
| * ext4_try_to_allocate_with_rsv() |
| * @sb: superblock |
| * @handle: handle to this transaction |
| * @group: given allocation block group |
| * @bitmap_bh: bufferhead holds the block bitmap |
| * @grp_goal: given target block within the group |
| * @count: target number of blocks to allocate |
| * @my_rsv: reservation window |
| * @errp: pointer to store the error code |
| * |
| * This is the main function used to allocate a new block and its reservation |
| * window. |
| * |
| * Each time when a new block allocation is need, first try to allocate from |
| * its own reservation. If it does not have a reservation window, instead of |
| * looking for a free bit on bitmap first, then look up the reservation list to |
| * see if it is inside somebody else's reservation window, we try to allocate a |
| * reservation window for it starting from the goal first. Then do the block |
| * allocation within the reservation window. |
| * |
| * This will avoid keeping on searching the reservation list again and |
| * again when somebody is looking for a free block (without |
| * reservation), and there are lots of free blocks, but they are all |
| * being reserved. |
| * |
| * We use a red-black tree for the per-filesystem reservation list. |
| * |
| */ |
| static ext4_grpblk_t |
| ext4_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle, |
| ext4_group_t group, struct buffer_head *bitmap_bh, |
| ext4_grpblk_t grp_goal, |
| struct ext4_reserve_window_node * my_rsv, |
| unsigned long *count, int *errp) |
| { |
| ext4_fsblk_t group_first_block, group_last_block; |
| ext4_grpblk_t ret = 0; |
| int fatal; |
| unsigned long num = *count; |
| |
| *errp = 0; |
| |
| /* |
| * Make sure we use undo access for the bitmap, because it is critical |
| * that we do the frozen_data COW on bitmap buffers in all cases even |
| * if the buffer is in BJ_Forget state in the committing transaction. |
| */ |
| BUFFER_TRACE(bitmap_bh, "get undo access for new block"); |
| fatal = ext4_journal_get_undo_access(handle, bitmap_bh); |
| if (fatal) { |
| *errp = fatal; |
| return -1; |
| } |
| |
| /* |
| * we don't deal with reservation when |
| * filesystem is mounted without reservation |
| * or the file is not a regular file |
| * or last attempt to allocate a block with reservation turned on failed |
| */ |
| if (my_rsv == NULL ) { |
| ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
| grp_goal, count, NULL); |
| goto out; |
| } |
| /* |
| * grp_goal is a group relative block number (if there is a goal) |
| * 0 <= grp_goal < EXT4_BLOCKS_PER_GROUP(sb) |
| * first block is a filesystem wide block number |
| * first block is the block number of the first block in this group |
| */ |
| group_first_block = ext4_group_first_block_no(sb, group); |
| group_last_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); |
| |
| /* |
| * Basically we will allocate a new block from inode's reservation |
| * window. |
| * |
| * We need to allocate a new reservation window, if: |
| * a) inode does not have a reservation window; or |
| * b) last attempt to allocate a block from existing reservation |
| * failed; or |
| * c) we come here with a goal and with a reservation window |
| * |
| * We do not need to allocate a new reservation window if we come here |
| * at the beginning with a goal and the goal is inside the window, or |
| * we don't have a goal but already have a reservation window. |
| * then we could go to allocate from the reservation window directly. |
| */ |
| while (1) { |
| if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || |
| !goal_in_my_reservation(&my_rsv->rsv_window, |
| grp_goal, group, sb)) { |
| if (my_rsv->rsv_goal_size < *count) |
| my_rsv->rsv_goal_size = *count; |
| ret = alloc_new_reservation(my_rsv, grp_goal, sb, |
| group, bitmap_bh); |
| if (ret < 0) |
| break; /* failed */ |
| |
| if (!goal_in_my_reservation(&my_rsv->rsv_window, |
| grp_goal, group, sb)) |
| grp_goal = -1; |
| } else if (grp_goal >= 0) { |
| int curr = my_rsv->rsv_end - |
| (grp_goal + group_first_block) + 1; |
| |
| if (curr < *count) |
| try_to_extend_reservation(my_rsv, sb, |
| *count - curr); |
| } |
| |
| if ((my_rsv->rsv_start > group_last_block) || |
| (my_rsv->rsv_end < group_first_block)) { |
| rsv_window_dump(&EXT4_SB(sb)->s_rsv_window_root, 1); |
| BUG(); |
| } |
| ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh, |
| grp_goal, &num, &my_rsv->rsv_window); |
| if (ret >= 0) { |
| my_rsv->rsv_alloc_hit += num; |
| *count = num; |
| break; /* succeed */ |
| } |
| num = *count; |
| } |
| out: |
| if (ret >= 0) { |
| BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for " |
| "bitmap block"); |
| fatal = ext4_journal_dirty_metadata(handle, bitmap_bh); |
| if (fatal) { |
| *errp = fatal; |
| return -1; |
| } |
| return ret; |
| } |
| |
| BUFFER_TRACE(bitmap_bh, "journal_release_buffer"); |
| ext4_journal_release_buffer(handle, bitmap_bh); |
| return ret; |
| } |
| |
| /** |
| * ext4_has_free_blocks() |
| * @sbi: in-core super block structure. |
| * |
| * Check if filesystem has at least 1 free block available for allocation. |
| */ |
| static int ext4_has_free_blocks(struct ext4_sb_info *sbi) |
| { |
| ext4_fsblk_t free_blocks, root_blocks; |
| |
| free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); |
| root_blocks = ext4_r_blocks_count(sbi->s_es); |
| if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && |
| sbi->s_resuid != current->fsuid && |
| (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { |
| return 0; |
| } |
| return 1; |
| } |
| |
| /** |
| * ext4_should_retry_alloc() |
| * @sb: super block |
| * @retries number of attemps has been made |
| * |
| * ext4_should_retry_alloc() is called when ENOSPC is returned, and if |
| * it is profitable to retry the operation, this function will wait |
| * for the current or commiting transaction to complete, and then |
| * return TRUE. |
| * |
| * if the total number of retries exceed three times, return FALSE. |
| */ |
| int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
| { |
| if (!ext4_has_free_blocks(EXT4_SB(sb)) || (*retries)++ > 3) |
| return 0; |
| |
| jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); |
| |
| return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); |
| } |
| |
| /** |
| * ext4_new_blocks_old() -- core block(s) allocation function |
| * @handle: handle to this transaction |
| * @inode: file inode |
| * @goal: given target block(filesystem wide) |
| * @count: target number of blocks to allocate |
| * @errp: error code |
| * |
| * ext4_new_blocks uses a goal block to assist allocation. It tries to |
| * allocate block(s) from the block group contains the goal block first. If that |
| * fails, it will try to allocate block(s) from other block groups without |
| * any specific goal block. |
| * |
| */ |
| ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode, |
| ext4_fsblk_t goal, unsigned long *count, int *errp) |
| { |
| struct buffer_head *bitmap_bh = NULL; |
| struct buffer_head *gdp_bh; |
| ext4_group_t group_no; |
| ext4_group_t goal_group; |
| ext4_grpblk_t grp_target_blk; /* blockgroup relative goal block */ |
| ext4_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ |
| ext4_fsblk_t ret_block; /* filesyetem-wide allocated block */ |
| ext4_group_t bgi; /* blockgroup iteration index */ |
| int fatal = 0, err; |
| int performed_allocation = 0; |
| ext4_grpblk_t free_blocks; /* number of free blocks in a group */ |
| struct super_block *sb; |
| struct ext4_group_desc *gdp; |
| struct ext4_super_block *es; |
| struct ext4_sb_info *sbi; |
| struct ext4_reserve_window_node *my_rsv = NULL; |
| struct ext4_block_alloc_info *block_i; |
| unsigned short windowsz = 0; |
| ext4_group_t ngroups; |
| unsigned long num = *count; |
| |
| *errp = -ENOSPC; |
| sb = inode->i_sb; |
| if (!sb) { |
| printk("ext4_new_block: nonexistent device"); |
| return 0; |
| } |
| |
| /* |
| * Check quota for allocation of this block. |
| */ |
| if (DQUOT_ALLOC_BLOCK(inode, num)) { |
| *errp = -EDQUOT; |
| return 0; |
| } |
| |
| sbi = EXT4_SB(sb); |
| es = EXT4_SB(sb)->s_es; |
| ext4_debug("goal=%llu.\n", goal); |
| /* |
| * Allocate a block from reservation only when |
| * filesystem is mounted with reservation(default,-o reservation), and |
| * it's a regular file, and |
| * the desired window size is greater than 0 (One could use ioctl |
| * command EXT4_IOC_SETRSVSZ to set the window size to 0 to turn off |
| * reservation on that particular file) |
| */ |
| block_i = EXT4_I(inode)->i_block_alloc_info; |
| if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0)) |
| my_rsv = &block_i->rsv_window_node; |
| |
| if (!ext4_has_free_blocks(sbi)) { |
| *errp = -ENOSPC; |
| goto out; |
| } |
| |
| /* |
| * First, test whether the goal block is free. |
| */ |
| 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_no, &grp_target_blk); |
| goal_group = group_no; |
| retry_alloc: |
| gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
| if (!gdp) |
| goto io_error; |
| |
| free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
| /* |
| * if there is not enough free blocks to make a new resevation |
| * turn off reservation for this allocation |
| */ |
| if (my_rsv && (free_blocks < windowsz) |
| && (rsv_is_empty(&my_rsv->rsv_window))) |
| my_rsv = NULL; |
| |
| if (free_blocks > 0) { |
| bitmap_bh = ext4_read_block_bitmap(sb, group_no); |
| if (!bitmap_bh) |
| goto io_error; |
| grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
| group_no, bitmap_bh, grp_target_blk, |
| my_rsv, &num, &fatal); |
| if (fatal) |
| goto out; |
| if (grp_alloc_blk >= 0) |
| goto allocated; |
| } |
| |
| ngroups = EXT4_SB(sb)->s_groups_count; |
| smp_rmb(); |
| |
| /* |
| * Now search the rest of the groups. We assume that |
| * group_no and gdp correctly point to the last group visited. |
| */ |
| for (bgi = 0; bgi < ngroups; bgi++) { |
| group_no++; |
| if (group_no >= ngroups) |
| group_no = 0; |
| gdp = ext4_get_group_desc(sb, group_no, &gdp_bh); |
| if (!gdp) |
| goto io_error; |
| free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); |
| /* |
| * skip this group if the number of |
| * free blocks is less than half of the reservation |
| * window size. |
| */ |
| if (free_blocks <= (windowsz/2)) |
| continue; |
| |
| brelse(bitmap_bh); |
| bitmap_bh = ext4_read_block_bitmap(sb, group_no); |
| if (!bitmap_bh) |
| goto io_error; |
| /* |
| * try to allocate block(s) from this group, without a goal(-1). |
| */ |
| grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle, |
| group_no, bitmap_bh, -1, my_rsv, |
| &num, &fatal); |
| if (fatal) |
| goto out; |
| if (grp_alloc_blk >= 0) |
| goto allocated; |
| } |
| /* |
| * We may end up a bogus ealier ENOSPC error due to |
| * filesystem is "full" of reservations, but |
| * there maybe indeed free blocks avaliable on disk |
| * In this case, we just forget about the reservations |
| * just do block allocation as without reservations. |
| */ |
| if (my_rsv) { |
| my_rsv = NULL; |
| windowsz = 0; |
| group_no = goal_group; |
| goto retry_alloc; |
| } |
| /* No space left on the device */ |
| *errp = -ENOSPC; |
| goto out; |
| |
| allocated: |
| |
| ext4_debug("using block group %lu(%d)\n", |
| group_no, gdp->bg_free_blocks_count); |
| |
| BUFFER_TRACE(gdp_bh, "get_write_access"); |
| fatal = ext4_journal_get_write_access(handle, gdp_bh); |
| if (fatal) |
| goto out; |
| |
| ret_block = grp_alloc_blk + ext4_group_first_block_no(sb, group_no); |
| |
| if (in_range(ext4_block_bitmap(sb, gdp), ret_block, num) || |
| in_range(ext4_inode_bitmap(sb, gdp), ret_block, num) || |
| in_range(ret_block, ext4_inode_table(sb, gdp), |
| EXT4_SB(sb)->s_itb_per_group) || |
| in_range(ret_block + num - 1, ext4_inode_table(sb, gdp), |
| EXT4_SB(sb)->s_itb_per_group)) { |
| ext4_error(sb, "ext4_new_block", |
| "Allocating block in system zone - " |
| "blocks from %llu, length %lu", |
| ret_block, num); |
| /* |
| * claim_block marked the blocks we allocated |
| * as in use. So we may want to selectively |
| * mark some of the blocks as free |
| */ |
| goto retry_alloc; |
| } |
| |
| performed_allocation = 1; |
| |
| #ifdef CONFIG_JBD2_DEBUG |
| { |
| struct buffer_head *debug_bh; |
| |
| /* Record bitmap buffer state in the newly allocated block */ |
| debug_bh = sb_find_get_block(sb, ret_block); |
| if (debug_bh) { |
| BUFFER_TRACE(debug_bh, "state when allocated"); |
| BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state"); |
| brelse(debug_bh); |
| } |
| } |
| jbd_lock_bh_state(bitmap_bh); |
| spin_lock(sb_bgl_lock(sbi, group_no)); |
| if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) { |
| int i; |
| |
| for (i = 0; i < num; i++) { |
| if (ext4_test_bit(grp_alloc_blk+i, |
| bh2jh(bitmap_bh)->b_committed_data)) { |
| printk("%s: block was unexpectedly set in " |
| "b_committed_data\n", __func__); |
| } |
| } |
| } |
| ext4_debug("found bit %d\n", grp_alloc_blk); |
| spin_unlock(sb_bgl_lock(sbi, group_no)); |
| jbd_unlock_bh_state(bitmap_bh); |
| #endif |
| |
| if (ret_block + num - 1 >= ext4_blocks_count(es)) { |
| ext4_error(sb, "ext4_new_block", |
| "block(%llu) >= blocks count(%llu) - " |
| "block_group = %lu, es == %p ", ret_block, |
| ext4_blocks_count(es), group_no, es); |
| goto out; |
| } |
| |
| /* |
| * It is up to the caller to add the new buffer to a journal |
| * list of some description. We don't know in advance whether |
| * the caller wants to use it as metadata or data. |
| */ |
| spin_lock(sb_bgl_lock(sbi, group_no)); |
| if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) |
| gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); |
| le16_add_cpu(&gdp->bg_free_blocks_count, -num); |
| gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp); |
| spin_unlock(sb_bgl_lock(sbi, group_no)); |
| percpu_counter_sub(&sbi->s_freeblocks_counter, num); |
| |
| if (sbi->s_log_groups_per_flex) { |
| ext4_group_t flex_group = ext4_flex_group(sbi, group_no); |
| spin_lock(sb_bgl_lock(sbi, flex_group)); |
| sbi->s_flex_groups[flex_group].free_blocks -= num; |
| spin_unlock(sb_bgl_lock(sbi, flex_group)); |
| } |
| |
| BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor"); |
| err = ext4_journal_dirty_metadata(handle, gdp_bh); |
| if (!fatal) |
| fatal = err; |
| |
| sb->s_dirt = 1; |
| if (fatal) |
| goto out; |
| |
| *errp = 0; |
| brelse(bitmap_bh); |
| DQUOT_FREE_BLOCK(inode, *count-num); |
| *count = num; |
| return ret_block; |
| |
| io_error: |
| *errp = -EIO; |
| out: |
| if (fatal) { |
| *errp = fatal; |
| ext4_std_error(sb, fatal); |
| } |
| /* |
| * Undo the block allocation |
| */ |
| if (!performed_allocation) |
| DQUOT_FREE_BLOCK(inode, *count); |
| brelse(bitmap_bh); |
| return 0; |
| } |
| |
| ext4_fsblk_t ext4_new_block(handle_t *handle, struct inode *inode, |
| ext4_fsblk_t goal, int *errp) |
| { |
| struct ext4_allocation_request ar; |
| ext4_fsblk_t ret; |
| |
| if (!test_opt(inode->i_sb, MBALLOC)) { |
| unsigned long count = 1; |
| ret = ext4_new_blocks_old(handle, inode, goal, &count, errp); |
| return ret; |
| } |
| |
| memset(&ar, 0, sizeof(ar)); |
| ar.inode = inode; |
| ar.goal = goal; |
| ar.len = 1; |
| ret = ext4_mb_new_blocks(handle, &ar, errp); |
| return ret; |
| } |
| |
| ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode, |
| ext4_fsblk_t goal, unsigned long *count, int *errp) |
| { |
| struct ext4_allocation_request ar; |
| ext4_fsblk_t ret; |
| |
| if (!test_opt(inode->i_sb, MBALLOC)) { |
| ret = ext4_new_blocks_old(handle, inode, goal, count, errp); |
| return ret; |
| } |
| |
| memset(&ar, 0, sizeof(ar)); |
| ar.inode = inode; |
| ar.goal = goal; |
| ar.len = *count; |
| ret = ext4_mb_new_blocks(handle, &ar, errp); |
| *count = ar.len; |
| return ret; |
| } |
| |
| |
| /** |
| * ext4_count_free_blocks() -- count filesystem free blocks |
| * @sb: superblock |
| * |
| * Adds up the number of free blocks from each block group. |
| */ |
| ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) |
| { |
| ext4_fsblk_t desc_count; |
| struct ext4_group_desc *gdp; |
| ext4_group_t i; |
| ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count; |
| #ifdef EXT4FS_DEBUG |
| struct ext4_super_block *es; |
| ext4_fsblk_t bitmap_count; |
| unsigned long x; |
| struct buffer_head *bitmap_bh = NULL; |
| |
| es = EXT4_SB(sb)->s_es; |
| desc_count = 0; |
| bitmap_count = 0; |
| gdp = NULL; |
| |
| smp_rmb(); |
| for (i = 0; i < ngroups; i++) { |
| gdp = ext4_get_group_desc(sb, i, NULL); |
| if (!gdp) |
| continue; |
| desc_count += le16_to_cpu(gdp->bg_free_blocks_count); |
| brelse(bitmap_bh); |
| bitmap_bh = ext4_read_block_bitmap(sb, i); |
| if (bitmap_bh == NULL) |
| continue; |
| |
| x = ext4_count_free(bitmap_bh, sb->s_blocksize); |
| printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n", |
| i, le16_to_cpu(gdp->bg_free_blocks_count), x); |
| bitmap_count += x; |
| } |
| brelse(bitmap_bh); |
| printk("ext4_count_free_blocks: stored = %llu" |
| ", computed = %llu, %llu\n", |
| ext4_free_blocks_count(es), |
| desc_count, bitmap_count); |
| return bitmap_count; |
| #else |
| desc_count = 0; |
| smp_rmb(); |
| for (i = 0; i < ngroups; i++) { |
| gdp = ext4_get_group_desc(sb, i, NULL); |
| if (!gdp) |
| continue; |
| desc_count += le16_to_cpu(gdp->bg_free_blocks_count); |
| } |
| |
| return desc_count; |
| #endif |
| } |
| |
| static inline int test_root(ext4_group_t a, int b) |
| { |
| int num = b; |
| |
| while (a > num) |
| num *= b; |
| return num == a; |
| } |
| |
| static int ext4_group_sparse(ext4_group_t group) |
| { |
| if (group <= 1) |
| return 1; |
| if (!(group & 1)) |
| return 0; |
| return (test_root(group, 7) || test_root(group, 5) || |
| test_root(group, 3)); |
| } |
| |
| /** |
| * ext4_bg_has_super - number of blocks used by the superblock in group |
| * @sb: superblock for filesystem |
| * @group: group number to check |
| * |
| * Return the number of blocks used by the superblock (primary or backup) |
| * in this group. Currently this will be only 0 or 1. |
| */ |
| int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) |
| { |
| if (EXT4_HAS_RO_COMPAT_FEATURE(sb, |
| EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && |
| !ext4_group_sparse(group)) |
| return 0; |
| return 1; |
| } |
| |
| static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, |
| ext4_group_t group) |
| { |
| unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
| ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); |
| ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; |
| |
| if (group == first || group == first + 1 || group == last) |
| return 1; |
| return 0; |
| } |
| |
| static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, |
| ext4_group_t group) |
| { |
| return ext4_bg_has_super(sb, group) ? EXT4_SB(sb)->s_gdb_count : 0; |
| } |
| |
| /** |
| * ext4_bg_num_gdb - number of blocks used by the group table in group |
| * @sb: superblock for filesystem |
| * @group: group number to check |
| * |
| * Return the number of blocks used by the group descriptor table |
| * (primary or backup) in this group. In the future there may be a |
| * different number of descriptor blocks in each group. |
| */ |
| unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) |
| { |
| unsigned long first_meta_bg = |
| le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
| unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
| |
| if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || |
| metagroup < first_meta_bg) |
| return ext4_bg_num_gdb_nometa(sb,group); |
| |
| return ext4_bg_num_gdb_meta(sb,group); |
| |
| } |