A user reported a bug of btrfs's trim, that is we will trim 0 bytes
after a device delete.
The reproducer:
$ mkfs.btrfs disk1
$ mkfs.btrfs disk2
$ mount disk1 /mnt
$ fstrim -v /mnt
$ btrfs device add disk2 /mnt
$ btrfs device del disk1 /mnt
$ fstrim -v /mnt
This is because after we delete the device, the block group may start from
a non-zero place, which will confuse trim to discard nothing.
Reported-by: Lutz Euler <lutz.euler@xxxxxxxxxx>
Signed-off-by: Liu Bo <liubo2009@xxxxxxxxxxxxxx>
---
fs/btrfs/extent-tree.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 77ea23c..b6e2c92 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7653,9 +7653,16 @@ int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
u64 start;
u64 end;
u64 trimmed = 0;
+ u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
int ret = 0;
- cache = btrfs_lookup_block_group(fs_info, range->start);
+ /*
+ * try to trim all FS space, our block group may start from non-zero.
+ */
+ if (range->len == total_bytes)
+ cache = btrfs_lookup_first_block_group(fs_info, range->start);
+ else
+ cache = btrfs_lookup_block_group(fs_info, range->start);
while (cache) {
if (cache->key.objectid >= (range->start + range->len)) {
--
1.6.5.2
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