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Btrfs: cow file extents before writing 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-04-10 13:20:21 -04:00 committed by David Woodhouse
parent d0dbc6245c
commit 48ddc6f44b
1 changed files with 18 additions and 2 deletions
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20
fs/btrfs/super.c
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@ -1020,7 +1020,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
ret = btrfs_lookup_file_extent(trans, root, path,
inode->i_ino,
iblock << inode->i_blkbits, 0);
iblock << inode->i_blkbits, 1);
if (ret < 0) {
err = ret;
goto out;
@ -1040,9 +1040,25 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
blocknr = btrfs_file_extent_disk_blocknr(item);
blocknr += btrfs_file_extent_offset(item);
/* exact match found, use it */
/* exact match found, use it, FIXME, deal with extents
* other than the page size
*/
if (ret == 0) {
err = 0;
BUG_ON(btrfs_file_extent_disk_num_blocks(item) != 1);
if (btrfs_file_extent_generation(item) != trans->transid) {
struct btrfs_key ins;
ret = btrfs_alloc_extent(trans, root, 1,
blocknr, (u64)-1, &ins);
BUG_ON(ret);
btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
mark_buffer_dirty(path->nodes[0]);
ret = btrfs_free_extent(trans, root,
blocknr, 1, 0);
BUG_ON(ret);
blocknr = ins.objectid;
}
map_bh(result, inode->i_sb, blocknr);
goto out;
}