From 2cac13e41bf5b99ffc426bd28dfd2248df1dfa67 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Thu, 9 Feb 2012 18:17:41 +0800 Subject: [PATCH] Btrfs: fix trim 0 bytes after a device delete 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 Signed-off-by: Liu Bo --- fs/btrfs/extent-tree.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 283af7a..60bfe2d 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7886,9 +7886,16 @@ 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)) { -- 2.7.4