redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

btrfs: ensure removal of discardable_* in free_bitmap() 

Most callers of free_bitmap() only call it if bitmap_info->bytes is 0.
However, there are certain cases where we may free the free space cache
via __btrfs_remove_free_space_cache(). This exposes a path where
free_bitmap() is called regardless. This may result in a bad accounting
situation for discardable_bytes and discardable_extents. So, remove the
stats and call btrfs_discard_update_discardable().

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
alistair/sensors
Dennis Zhou 2020-01-02 16:26:45 -05:00 committed by David Sterba
parent f9bb615af2
commit 27f0afc737
1 changed files with 14 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
fs/btrfs/free-space-cache.c
View File

@ -1959,6 +1959,18 @@ static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
static void free_bitmap(struct btrfs_free_space_ctl *ctl,
struct btrfs_free_space *bitmap_info)
{
/*
* Normally when this is called, the bitmap is completely empty. However,
* if we are blowing up the free space cache for one reason or another
* via __btrfs_remove_free_space_cache(), then it may not be freed and
* we may leave stats on the table.
*/
if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
ctl->discardable_extents[BTRFS_STAT_CURR] -=
bitmap_info->bitmap_extents;
ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
}
unlink_free_space(ctl, bitmap_info);
kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
@ -2776,6 +2788,8 @@ void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
{
spin_lock(&ctl->tree_lock);
__btrfs_remove_free_space_cache_locked(ctl);
if (ctl->private)
btrfs_discard_update_discardable(ctl->private, ctl);
spin_unlock(&ctl->tree_lock);
}