Btrfs: Extent based page cache code. This uses an rbtree of extents and tests
instead of buffer heads.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 6933ab1..71a4818 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -81,14 +81,14 @@
}
}
-static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
+static int insert_inline_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct inode *inode,
u64 offset, ssize_t size,
- struct buffer_head *bh)
+ struct page *page, size_t page_offset)
{
struct btrfs_key key;
struct btrfs_path *path;
char *ptr, *kaddr;
- struct btrfs_trans_handle *trans;
struct btrfs_file_extent_item *ei;
u32 datasize;
int err = 0;
@@ -98,8 +98,6 @@
if (!path)
return -ENOMEM;
- mutex_lock(&root->fs_info->fs_mutex);
- trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
key.objectid = inode->i_ino;
@@ -122,18 +120,13 @@
BTRFS_FILE_EXTENT_INLINE);
ptr = btrfs_file_extent_inline_start(ei);
- kaddr = kmap_atomic(bh->b_page, KM_USER0);
+ kaddr = kmap_atomic(page, KM_USER0);
btrfs_memcpy(root, path->nodes[0]->b_data,
- ptr, kaddr + bh_offset(bh),
- size);
+ ptr, kaddr + page_offset, size);
kunmap_atomic(kaddr, KM_USER0);
btrfs_mark_buffer_dirty(path->nodes[0]);
fail:
btrfs_free_path(path);
- ret = btrfs_end_transaction(trans, root);
- if (ret && !err)
- err = ret;
- mutex_unlock(&root->fs_info->fs_mutex);
return err;
}
@@ -145,45 +138,143 @@
loff_t pos,
size_t write_bytes)
{
- int i;
- int offset;
int err = 0;
- int ret;
- int this_write;
+ int i;
struct inode *inode = file->f_path.dentry->d_inode;
- struct buffer_head *bh;
+ struct extent_map *em;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ struct btrfs_key ins;
+ u64 hint_block;
+ u64 num_blocks;
+ u64 start_pos;
+ u64 end_of_last_block;
+ u64 end_pos = pos + write_bytes;
+ loff_t isize = i_size_read(inode);
- for (i = 0; i < num_pages; i++) {
- offset = pos & (PAGE_CACHE_SIZE -1);
- this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
+ em = alloc_extent_map(GFP_NOFS);
+ if (!em)
+ return -ENOMEM;
- /* FIXME, one block at a time */
- bh = page_buffers(pages[i]);
+ em->bdev = inode->i_sb->s_bdev;
- if (buffer_mapped(bh) && bh->b_blocknr == 0) {
- ret = insert_inline_extent(root, inode,
- pages[i]->index << PAGE_CACHE_SHIFT,
- offset + this_write, bh);
- if (ret) {
- err = ret;
- goto failed;
- }
- }
+ start_pos = pos & ~((u64)root->blocksize - 1);
+ num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
+ inode->i_blkbits;
- ret = btrfs_commit_write(file, pages[i], offset,
- offset + this_write);
- pos += this_write;
- if (ret) {
- err = ret;
+ end_of_last_block = start_pos + (num_blocks << inode->i_blkbits) - 1;
+ mutex_lock(&root->fs_info->fs_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ if (!trans) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+ btrfs_set_trans_block_group(trans, inode);
+ inode->i_blocks += num_blocks << 3;
+ hint_block = 0;
+
+ if ((end_of_last_block & 4095) == 0) {
+ printk("strange end of last %Lu %lu %Lu\n", start_pos, write_bytes, end_of_last_block);
+ }
+ set_extent_uptodate(em_tree, start_pos, end_of_last_block, GFP_NOFS);
+
+ /* FIXME...EIEIO, ENOSPC and more */
+
+ /* step one, delete the existing extents in this range */
+ /* FIXME blocksize != pagesize */
+ if (start_pos < inode->i_size) {
+ err = btrfs_drop_extents(trans, root, inode,
+ start_pos, (pos + write_bytes + root->blocksize -1) &
+ ~((u64)root->blocksize - 1), &hint_block);
+ if (err)
goto failed;
+ }
+
+ /* insert any holes we need to create */
+ if (inode->i_size < start_pos) {
+ u64 last_pos_in_file;
+ u64 hole_size;
+ u64 mask = root->blocksize - 1;
+ last_pos_in_file = (isize + mask) & ~mask;
+ hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
+ hole_size >>= inode->i_blkbits;
+ if (last_pos_in_file < start_pos) {
+ err = btrfs_insert_file_extent(trans, root,
+ inode->i_ino,
+ last_pos_in_file,
+ 0, 0, hole_size);
}
- WARN_ON(this_write > write_bytes);
- write_bytes -= this_write;
+ if (err)
+ goto failed;
+ }
+
+ /*
+ * either allocate an extent for the new bytes or setup the key
+ * to show we are doing inline data in the extent
+ */
+ if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
+ pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
+ err = btrfs_alloc_extent(trans, root, inode->i_ino,
+ num_blocks, 0, hint_block, (u64)-1,
+ &ins, 1);
+ BUG_ON(err);
+ err = btrfs_insert_file_extent(trans, root, inode->i_ino,
+ start_pos, ins.objectid, ins.offset,
+ ins.offset);
+ BUG_ON(err);
+ em->start = start_pos;
+ em->end = end_of_last_block;
+ em->block_start = ins.objectid << inode->i_blkbits;
+ em->block_end = em->block_start +
+ (ins.offset << inode->i_blkbits) - 1;
+ set_extent_dirty(em_tree, start_pos, end_of_last_block,
+ GFP_NOFS);
+ err = add_extent_mapping(em_tree, em);
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = pages[i];
+ SetPageUptodate(p);
+ __set_page_dirty_nobuffers(p);
+ }
+ } else {
+ struct page *p = pages[0];
+ err = insert_inline_extent(trans, root, inode, start_pos,
+ end_pos - start_pos, p, 0);
+ BUG_ON(err);
+ em->start = start_pos;
+ em->end = end_pos;
+ em->block_start = EXTENT_MAP_INLINE;
+ em->block_end = EXTENT_MAP_INLINE;
+ add_extent_mapping(em_tree, em);
+ }
+ if (end_pos > isize) {
+ i_size_write(inode, end_pos);
+ btrfs_update_inode(trans, root, inode);
}
failed:
+ err = btrfs_end_transaction(trans, root);
+out_unlock:
+ mutex_unlock(&root->fs_info->fs_mutex);
+ free_extent_map(em);
return err;
}
+int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
+{
+ struct extent_map *em;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+
+ while(1) {
+ em = lookup_extent_mapping(em_tree, start, end);
+ if (!em)
+ break;
+ remove_extent_mapping(em_tree, em);
+ /* once for us */
+ free_extent_map(em);
+ /* once for the tree*/
+ free_extent_map(em);
+ }
+ return 0;
+}
+
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
@@ -213,6 +304,8 @@
int found_inline;
int recow;
+ btrfs_drop_extent_cache(inode, start, end - 1);
+
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
@@ -434,18 +527,9 @@
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file->f_path.dentry->d_inode;
- int offset;
int err = 0;
- int this_write;
- struct buffer_head *bh;
- struct buffer_head *head;
- loff_t isize = i_size_read(inode);
- struct btrfs_trans_handle *trans;
- u64 hint_block;
u64 num_blocks;
- u64 alloc_extent_start;
u64 start_pos;
- struct btrfs_key ins;
start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
@@ -457,119 +541,17 @@
pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) {
err = -ENOMEM;
- goto failed_release;
+ BUG_ON(1);
}
cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
wait_on_page_writeback(pages[i]);
- }
-
- mutex_lock(&root->fs_info->fs_mutex);
- trans = btrfs_start_transaction(root, 1);
- if (!trans) {
- err = -ENOMEM;
- mutex_unlock(&root->fs_info->fs_mutex);
- goto out_unlock;
- }
- btrfs_set_trans_block_group(trans, inode);
- /* FIXME blocksize != 4096 */
- inode->i_blocks += num_blocks << 3;
- hint_block = 0;
-
- /* FIXME...EIEIO, ENOSPC and more */
-
- /* step one, delete the existing extents in this range */
- /* FIXME blocksize != pagesize */
- if (start_pos < inode->i_size) {
- err = btrfs_drop_extents(trans, root, inode,
- start_pos, (pos + write_bytes + root->blocksize -1) &
- ~((u64)root->blocksize - 1), &hint_block);
- if (err)
- goto failed_release;
- }
-
- /* insert any holes we need to create */
- if (inode->i_size < start_pos) {
- u64 last_pos_in_file;
- u64 hole_size;
- u64 mask = root->blocksize - 1;
- last_pos_in_file = (isize + mask) & ~mask;
- hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
- hole_size >>= inode->i_blkbits;
- if (last_pos_in_file < start_pos) {
- err = btrfs_insert_file_extent(trans, root,
- inode->i_ino,
- last_pos_in_file,
- 0, 0, hole_size);
+ if (!PagePrivate(pages[i])) {
+ SetPagePrivate(pages[i]);
+ set_page_private(pages[i], 1);
+ page_cache_get(pages[i]);
}
- if (err)
- goto failed_release;
- }
-
- /*
- * either allocate an extent for the new bytes or setup the key
- * to show we are doing inline data in the extent
- */
- if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
- pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
- err = btrfs_alloc_extent(trans, root, inode->i_ino,
- num_blocks, 0, hint_block, (u64)-1,
- &ins, 1);
- if (err)
- goto failed_truncate;
- err = btrfs_insert_file_extent(trans, root, inode->i_ino,
- start_pos, ins.objectid, ins.offset,
- ins.offset);
- if (err)
- goto failed_truncate;
- } else {
- ins.offset = 0;
- ins.objectid = 0;
- }
- BUG_ON(err);
- alloc_extent_start = ins.objectid;
- err = btrfs_end_transaction(trans, root);
- mutex_unlock(&root->fs_info->fs_mutex);
-
- for (i = 0; i < num_pages; i++) {
- offset = pos & (PAGE_CACHE_SIZE -1);
- this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
- if (!page_has_buffers(pages[i])) {
- create_empty_buffers(pages[i],
- root->fs_info->sb->s_blocksize,
- (1 << BH_Uptodate));
- }
- head = page_buffers(pages[i]);
- bh = head;
- do {
- err = btrfs_map_bh_to_logical(root, bh,
- alloc_extent_start);
- BUG_ON(err);
- if (err)
- goto failed_truncate;
- bh = bh->b_this_page;
- if (alloc_extent_start)
- alloc_extent_start++;
- } while (bh != head);
- pos += this_write;
- WARN_ON(this_write > write_bytes);
- write_bytes -= this_write;
}
return 0;
-
-failed_release:
- btrfs_drop_pages(pages, num_pages);
- return err;
-
-failed_truncate:
- btrfs_drop_pages(pages, num_pages);
- if (pos > isize)
- vmtruncate(inode, isize);
- return err;
-
-out_unlock:
- mutex_unlock(&root->fs_info->fs_mutex);
- goto failed_release;
-
}
static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
@@ -685,7 +667,6 @@
page_cache_release(pinned[1]);
*ppos = pos;
current->backing_dev_info = NULL;
- mark_inode_dirty(inode);
return num_written ? num_written : err;
}
@@ -714,8 +695,8 @@
mutex_unlock(&root->fs_info->trans_mutex);
/*
- * ok we haven't committed the transaction yet, lets do a commit
- */
+ * ok we haven't committed the transaction yet, lets do a commit
+ */
trans = btrfs_start_transaction(root, 1);
if (!trans) {
ret = -ENOMEM;