1 files changed, 62 insertions, 19 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index c9b863eacab7..525260c7617f 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -706,12 +706,43 @@ __xfs_inode_clear_reclaim_tag(
                         XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
 }
 
+/*
+ * Inodes in different states need to be treated differently, and the return
+ * value of xfs_iflush is not sufficient to get this right. The following table
+ * lists the inode states and the reclaim actions necessary for non-blocking
+ * reclaim:
+ *
+ *
+ *      inode state          iflush ret         required action
+ *      ---------------      ----------         ---------------
+ *      bad                     -               reclaim
+ *      shutdown                EIO             unpin and reclaim
+ *      clean, unpinned         0               reclaim
+ *      stale, unpinned         0               reclaim
+ *      clean, pinned(*)        0               unpin and reclaim
+ *      stale, pinned           0               unpin and reclaim
+ *      dirty, async            0               block on flush lock, reclaim
+ *      dirty, sync flush       0               block on flush lock, reclaim
+ *
+ * (*) dgc: I don't think the clean, pinned state is possible but it gets
+ * handled anyway given the order of checks implemented.
+ *
+ * Hence the order of actions after gaining the locks should be:
+ *      bad             => reclaim
+ *      shutdown        => unpin and reclaim
+ *      pinned          => unpin
+ *      stale           => reclaim
+ *      clean           => reclaim
+ *      dirty           => flush, wait and reclaim
+ */
 STATIC int
 xfs_reclaim_inode(
         struct xfs_inode        *ip,
         struct xfs_perag        *pag,
         int                     sync_mode)
 {
+        int     error;
+
         /*
          * The radix tree lock here protects a thread in xfs_iget from racing
          * with us starting reclaim on the inode.  Once we have the
@@ -729,30 +760,42 @@ xfs_reclaim_inode(
         spin_unlock(&ip->i_flags_lock);
         write_unlock(&pag->pag_ici_lock);
 
-        /*
-         * If the inode is still dirty, then flush it out.  If the inode
-         * is not in the AIL, then it will be OK to flush it delwri as
-         * long as xfs_iflush() does not keep any references to the inode.
-         * We leave that decision up to xfs_iflush() since it has the
-         * knowledge of whether it's OK to simply do a delwri flush of
-         * the inode or whether we need to wait until the inode is
-         * pulled from the AIL.
-         * We get the flush lock regardless, though, just to make sure
-         * we don't free it while it is being flushed.
-         */
         xfs_ilock(ip, XFS_ILOCK_EXCL);
         xfs_iflock(ip);
 
-        /*
-         * In the case of a forced shutdown we rely on xfs_iflush() to
-         * wait for the inode to be unpinned before returning an error.
-         */
-        if (!is_bad_inode(VFS_I(ip)) && xfs_iflush(ip, sync_mode) == 0) {
-                /* synchronize with xfs_iflush_done */
-                xfs_iflock(ip);
-                xfs_ifunlock(ip);
+        if (is_bad_inode(VFS_I(ip)))
+                goto reclaim;
+        if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+                xfs_iunpin_wait(ip);
+                goto reclaim;
+        }
+        if (xfs_ipincount(ip))
+                xfs_iunpin_wait(ip);
+        if (xfs_iflags_test(ip, XFS_ISTALE))
+                goto reclaim;
+        if (xfs_inode_clean(ip))
+                goto reclaim;
+
+        /* Now we have an inode that needs flushing */
+        error = xfs_iflush(ip, sync_mode);
+        if (!error) {
+                switch(sync_mode) {
+                case XFS_IFLUSH_DELWRI_ELSE_ASYNC:
+                case XFS_IFLUSH_DELWRI:
+                case XFS_IFLUSH_ASYNC:
+                case XFS_IFLUSH_DELWRI_ELSE_SYNC:
+                case XFS_IFLUSH_SYNC:
+                        /* IO issued, synchronise with IO completion */
+                        xfs_iflock(ip);
+                        break;
+                default:
+                        ASSERT(0);
+                        break;
+                }
         }
 
+reclaim:
+        xfs_ifunlock(ip);
         xfs_iunlock(ip, XFS_ILOCK_EXCL);
         xfs_ireclaim(ip);
         return 0;