There's an off-by-one bug:
# create a file with lots of 4K file extents
# btrfs fi defrag /mnt/file
# sync
# filefrag -v /mnt/file
Filesystem type is: 9123683e
File size of /mnt/file is 1228800 (300 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 3372 64
1 64 3136 3435 1
2 65 3436 3136 64
3 129 3201 3499 1
4 130 3500 3201 64
5 194 3266 3563 1
6 195 3564 3266 64
7 259 3331 3627 1
8 260 3628 3331 40 eof
After this patch:
...
# filefrag -v /mnt/file
Filesystem type is: 9123683e
File size of /mnt/file is 1228800 (300 blocks, blocksize 4096)
ext logical physical expected length flags
0 0 3372 300 eof
/mnt/file: 1 extent found
Signed-off-by: Li Zefan <l...@cn.fujitsu.com>
---
fs/btrfs/ioctl.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 970977a..31fe6d4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1081,7 +1081,6 @@ int btrfs_defrag_file(struct inode *inode, struct file
*file,
defrag_count += ret;
balance_dirty_pages_ratelimited_nr(inode->i_mapping, ret);
- i += ret;
if (newer_than) {
if (newer_off == (u64)-1)
@@ -1101,7 +1100,10 @@ int btrfs_defrag_file(struct inode *inode, struct file
*file,
break;
}
} else {
- i++;
+ if (ret > 0)
+ i += ret;
+ else
+ i++;
}
}
--
1.7.3.1
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