| Message ID | a9e6b02e9eb7a0532c401a898661b0511c31d0e8.1695047676.git.josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: properly report 0 avail for very full file systems | expand |
On Mon, Sep 18, 2023 at 10:34:51AM -0400, Josef Bacik wrote: > A user reported some issues with smaller file systems that get very > full. While investigating this issue I noticed that df wasn't showing > 100% full, despite having 0 chunk space and having < 1mib of available > metadata space. > > This turns out to be an overflow issue, we're doing > > total_available_metadata_space - SZ_4M < global_block_rsv_size > > to determine if there's not enough space to make metadata allocations, > which overflows if total_available_metadata_space is < 4M. Fix this by > checking to see if our available space is greater than the 4M threshold. > This makes df properly report 100% usage on the file system. > > Signed-off-by: Josef Bacik <josef@toxicpanda.com> Added to misc-next, thanks.
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index cffdd6f7f8e8..470ca9238544 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2117,7 +2117,8 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) * calculated f_bavail. */ if (!mixed && block_rsv->space_info->full && - total_free_meta - thresh < block_rsv->size) + (total_free_meta < thresh || + total_free_meta - thresh < block_rsv->size)) buf->f_bavail = 0; buf->f_type = BTRFS_SUPER_MAGIC;
A user reported some issues with smaller file systems that get very full. While investigating this issue I noticed that df wasn't showing 100% full, despite having 0 chunk space and having < 1mib of available metadata space. This turns out to be an overflow issue, we're doing total_available_metadata_space - SZ_4M < global_block_rsv_size to determine if there's not enough space to make metadata allocations, which overflows if total_available_metadata_space is < 4M. Fix this by checking to see if our available space is greater than the 4M threshold. This makes df properly report 100% usage on the file system. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- fs/btrfs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)