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btrfs: Ensure btrfs_trim_fs can trim the whole filesystem 

[BUG]
fstrim on some btrfs only trims the unallocated space, not trimming any
space in existing block groups.

[CAUSE]
Before fstrim_range passed to btrfs_trim_fs(), it gets truncated to
range [0, super->total_bytes).  So later btrfs_trim_fs() will only be
able to trim block groups in range [0, super->total_bytes).

While for btrfs, any bytenr aligned to sectorsize is valid, since btrfs
uses its logical address space, there is nothing limiting the location
where we put block groups.

For filesystem with frequent balance, it's quite easy to relocate all
block groups and bytenr of block groups will start beyond
super->total_bytes.

In that case, btrfs will not trim existing block groups.

[FIX]
Just remove the truncation in btrfs_ioctl_fitrim(), so btrfs_trim_fs()
can get the unmodified range, which is normally set to [0, U64_MAX].

Reported-by: Chris Murphy <lists@colorremedies.com>
Fixes: f4c697e640 ("btrfs: return EINVAL if start > total_bytes in fitrim ioctl")
CC: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2018-09-07 14:16:24 +08:00 committed by David Sterba
parent 93bba24d4b
commit 6ba9fc8e62
2 changed files with 8 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/btrfs/extent-tree.c
View File

@ -10851,21 +10851,13 @@ int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
u64 start;
u64 end;
u64 trimmed = 0;
u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
u64 bg_failed = 0;
u64 dev_failed = 0;
int bg_ret = 0;
int dev_ret = 0;
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);
cache = btrfs_lookup_first_block_group(fs_info, range->start);
for (; cache; cache = next_block_group(fs_info, cache)) {
if (cache->key.objectid >= (range->start + range->len)) {
btrfs_put_block_group(cache);

11
fs/btrfs/ioctl.c
View File

@ -491,7 +491,6 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
struct fstrim_range range;
u64 minlen = ULLONG_MAX;
u64 num_devices = 0;
u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
int ret;
if (!capable(CAP_SYS_ADMIN))
@ -515,11 +514,15 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
return -EOPNOTSUPP;
if (copy_from_user(&range, arg, sizeof(range)))
return -EFAULT;
if (range.start > total_bytes ||
range.len < fs_info->sb->s_blocksize)
/*
* NOTE: Don't truncate the range using super->total_bytes. Bytenr of
* block group is in the logical address space, which can be any
* sectorsize aligned bytenr in the range [0, U64_MAX].
*/
if (range.len < fs_info->sb->s_blocksize)
return -EINVAL;
range.len = min(range.len, total_bytes - range.start);
range.minlen = max(range.minlen, minlen);
ret = btrfs_trim_fs(fs_info, &range);
if (ret < 0)