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From: Eric Sandeen <sandeen@redhat.com>
To: xfs-oss <xfs@oss.sgi.com>
Subject: [PATCH] xfs: be honest about used inodes in statfs
Date: Thu, 20 Feb 2014 16:12:16 -0600	[thread overview]
Message-ID: <53067DC0.9040800@redhat.com> (raw)

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);
 

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             reply	other threads:[~2014-02-20 22:12 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-20 22:12 Eric Sandeen [this message]
2014-02-24 16:01 ` [PATCH] xfs: be honest about used inodes in statfs Brian Foster
2014-02-24 20:38   ` Eric Sandeen
2014-02-24 23:10 ` [PATCH V2] " Eric Sandeen
2014-02-24 23:55   ` Brian Foster
2014-02-24 23:56   ` Dave Chinner
2014-02-25  0:02     ` Eric Sandeen
2014-02-25  0:15 ` [PATCH V3] " Eric Sandeen
2014-02-25  0:27 ` [PATCH V4] " Eric Sandeen
2014-02-25  0:52   ` Dave Chinner

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