Commit 2cac13e4 authored Feb 09, 2012 by Liu Bo Committed by David Sterba Feb 15, 2012

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 <lutz.euler@freenet.de>
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>

parent 6af021d8

fs/btrfs/extent-tree.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -7886,8 +7886,15 @@ 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;

		/*
		* 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) {

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