Commit 66c26892 authored by Liu Bo's avatar Liu Bo Committed by Chris Mason

Btrfs: do not bother to defrag an extent if it is a big real extent

$ mkfs.btrfs /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs/ -oautodefrag
$ dd if=/dev/zero of=/mnt/btrfs/foobar bs=4k count=10 oflag=direct 2>/dev/null
$ filefrag -v /mnt/btrfs/foobar
Filesystem type is: 9123683e
File size of /mnt/btrfs/foobar is 40960 (10 blocks, blocksize 4096)
 ext logical physical expected length flags
   0       0     3072              10 eof
/mnt/btrfs/foobar: 1 extent found

Now we have a big real extent [0, 40960), but autodefrag will still defrag it.

$ sync
$ filefrag -v /mnt/btrfs/foobar
Filesystem type is: 9123683e
File size of /mnt/btrfs/foobar is 40960 (10 blocks, blocksize 4096)
 ext logical physical expected length flags
   0       0     3082              10 eof
/mnt/btrfs/foobar: 1 extent found

So if we already find a big real extent, we're ok about that, just skip it.
Signed-off-by: default avatarLiu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 17ce6ef8
...@@ -1140,12 +1140,9 @@ int btrfs_defrag_file(struct inode *inode, struct file *file, ...@@ -1140,12 +1140,9 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
if (!(inode->i_sb->s_flags & MS_ACTIVE)) if (!(inode->i_sb->s_flags & MS_ACTIVE))
break; break;
if (!newer_than && if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE, extent_thresh,
PAGE_CACHE_SIZE, &last_len, &skip, &defrag_end)) {
extent_thresh,
&last_len, &skip,
&defrag_end)) {
unsigned long next; unsigned long next;
/* /*
* the should_defrag function tells us how much to skip * the should_defrag function tells us how much to skip
......
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