[PATCH] xfs: be honest about used inodes in statfs

Eric Sandeen
2014-02-20T22:12:23Z

Because we have lazy counters, it's possible that we over-allocate
inodes past the maxicount (imaxpct) limit.

A previous commit,

2fe3366 xfs: ensure f_ffree returned by statfs() is non-negative

stopped statfs from underflowing f_ffree in this case, but that
only happened when we mis-reported f_files, capped at maxicount.

Change statfs to report the actual number of inodes allocated,
even if it is greater than maxicount. It's reality.
Deal with it. ;)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index f317488..7c7a810 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1083,7 +1083,6 @@ xfs_fs_statfs(
struct xfs_inode *ip = XFS_I(dentry->d_inode);
__uint64_t fakeinos, id;
xfs_extlen_t lsize;
- __int64_t ffree;

statp->f_type = XFS_SB_MAGIC;
statp->f_namelen = MAXNAMELEN - 1;
@@ -1100,17 +1099,24 @@ xfs_fs_statfs(
statp->f_blocks = sbp->sb_dblocks - lsize;
statp->f_bfree = statp->f_bavail =
sbp->sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
+
+ /* Potential number of new inodes in free blocks */
fakeinos = statp->f_bfree << sbp->sb_inopblog;
+ /* Total possible files is current inodes + potential new inodes */
statp->f_files =
MIN(sbp->sb_icount + fakeinos, (__uint64_t)XFS_MAXINUMBER);
+ /* Unless we have maxicount! Then cap it at that */
if (mp->m_maxicount)
statp->f_files = min_t(typeof(statp->f_files),
statp->f_files,
mp->m_maxicount);

- /* make sure statp->f_ffree does not underflow */
- ffree = statp->f_files - (sbp->sb_icount - sbp->sb_ifree);
- statp->f_ffree = max_t(__int64_t, ffree, 0);
+ /* But if we already managed to allocate more, let's be honest */
+ statp->f_files = max_t(typeof(statp->f_files),
+ sbp->sb_icount,
+ statp->f_files);
+
+ statp->f_ffree = statp->f_files - (sbp->sb_icount - sbp->sb_ifree);

spin_unlock(&mp->m_sb_lock);