xfs: make inode unlinked bucket recovery work with quotacheck

Teach quotacheck to reload the unlinked inode lists when walking the
inode table.  This requires extra state handling, since it's possible
that a reloaded inode will get inactivated before quotacheck tries to
scan it; in this case, we need to ensure that the reloaded inode does
not have dquots attached when it is freed.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/xfs_attr_inactive.c

@@ -333,7 +333,6 @@ xfs_attr_inactive(
 	int			error = 0;
 
 	mp = dp->i_mount;
-	ASSERT(! XFS_NOT_DQATTACHED(mp, dp));
 
 	xfs_ilock(dp, lock_mode);
 	if (!xfs_inode_has_attr_fork(dp))

fs/xfs/xfs_inode.c

@@ -1742,9 +1742,13 @@ xfs_inactive(
 	     ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0))
 		truncate = 1;
 
+	if (xfs_iflags_test(ip, XFS_IQUOTAUNCHECKED)) {
+		xfs_qm_dqdetach(ip);
+	} else {
 		error = xfs_qm_dqattach(ip);
 		if (error)
 			goto out;
+	}
 
 	if (S_ISLNK(VFS_I(ip)->i_mode))
 		error = xfs_inactive_symlink(ip);
@@ -1962,6 +1966,8 @@ xfs_iunlink_reload_next(
 	trace_xfs_iunlink_reload_next(next_ip);
 rele:
 	ASSERT(!(VFS_I(next_ip)->i_state & I_DONTCACHE));
+	if (xfs_is_quotacheck_running(mp) && next_ip)
+		xfs_iflags_set(next_ip, XFS_IQUOTAUNCHECKED);
 	xfs_irele(next_ip);
 	return error;
 }

fs/xfs/xfs_inode.h

@@ -344,6 +344,9 @@ static inline bool xfs_inode_has_large_extent_counts(struct xfs_inode *ip)
  */
 #define XFS_INACTIVATING	(1 << 13)
 
+/* Quotacheck is running but inode has not been added to quota counts. */
+#define XFS_IQUOTAUNCHECKED	(1 << 14)
+
 /* All inode state flags related to inode reclaim. */
 #define XFS_ALL_IRECLAIM_FLAGS	(XFS_IRECLAIMABLE | \
 				 XFS_IRECLAIM | \
@@ -358,7 +361,7 @@ static inline bool xfs_inode_has_large_extent_counts(struct xfs_inode *ip)
 #define XFS_IRECLAIM_RESET_FLAGS	\
 	(XFS_IRECLAIMABLE | XFS_IRECLAIM | \
 	 XFS_IDIRTY_RELEASE | XFS_ITRUNCATED | XFS_NEED_INACTIVE | \
-	 XFS_INACTIVATING)
+	 XFS_INACTIVATING | XFS_IQUOTAUNCHECKED)
 
 /*
  * Flags for inode locking.

fs/xfs/xfs_mount.h

@@ -405,6 +405,8 @@ __XFS_HAS_FEAT(nouuid, NOUUID)
 #define XFS_OPSTATE_WARNED_SHRINK	8
 /* Kernel has logged a warning about logged xattr updates being used. */
 #define XFS_OPSTATE_WARNED_LARP		9
+/* Mount time quotacheck is running */
+#define XFS_OPSTATE_QUOTACHECK_RUNNING	10
 
 #define __XFS_IS_OPSTATE(name, NAME) \
 static inline bool xfs_is_ ## name (struct xfs_mount *mp) \
@@ -427,6 +429,11 @@ __XFS_IS_OPSTATE(inode32, INODE32)
 __XFS_IS_OPSTATE(readonly, READONLY)
 __XFS_IS_OPSTATE(inodegc_enabled, INODEGC_ENABLED)
 __XFS_IS_OPSTATE(blockgc_enabled, BLOCKGC_ENABLED)
+#ifdef CONFIG_XFS_QUOTA
+__XFS_IS_OPSTATE(quotacheck_running, QUOTACHECK_RUNNING)
+#else
+# define xfs_is_quotacheck_running(mp)	(false)
+#endif
 
 static inline bool
 xfs_should_warn(struct xfs_mount *mp, long nr)
@@ -444,7 +451,8 @@ xfs_should_warn(struct xfs_mount *mp, long nr)
 	{ (1UL << XFS_OPSTATE_BLOCKGC_ENABLED),		"blockgc" }, \
 	{ (1UL << XFS_OPSTATE_WARNED_SCRUB),		"wscrub" }, \
 	{ (1UL << XFS_OPSTATE_WARNED_SHRINK),		"wshrink" }, \
-	{ (1UL << XFS_OPSTATE_WARNED_LARP),		"wlarp" }
+	{ (1UL << XFS_OPSTATE_WARNED_LARP),		"wlarp" }, \
+	{ (1UL << XFS_OPSTATE_QUOTACHECK_RUNNING),	"quotacheck" }
 
 /*
  * Max and min values for mount-option defined I/O

fs/xfs/xfs_qm.c

@@ -1160,6 +1160,10 @@ xfs_qm_dqusage_adjust(
 	if (error)
 		return error;
 
+	error = xfs_inode_reload_unlinked(ip);
+	if (error)
+		goto error0;
+
 	ASSERT(ip->i_delayed_blks == 0);
 
 	if (XFS_IS_REALTIME_INODE(ip)) {
@@ -1173,6 +1177,7 @@ xfs_qm_dqusage_adjust(
 	}
 
 	nblks = (xfs_qcnt_t)ip->i_nblocks - rtblks;
+	xfs_iflags_clear(ip, XFS_IQUOTAUNCHECKED);
 
 	/*
 	 * Add the (disk blocks and inode) resources occupied by this
@@ -1319,8 +1324,10 @@ xfs_qm_quotacheck(
 		flags |= XFS_PQUOTA_CHKD;
 	}
 
+	xfs_set_quotacheck_running(mp);
 	error = xfs_iwalk_threaded(mp, 0, 0, xfs_qm_dqusage_adjust, 0, true,
 			NULL);
+	xfs_clear_quotacheck_running(mp);
 
 	/*
 	 * On error, the inode walk may have partially populated the dquot