1 files changed, 82 insertions, 29 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 3b5b46b8e3b9..25ea2408118f 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1021,12 +1021,45 @@ xfs_fs_dirty_inode(
         XFS_I(inode)->i_update_core = 1;
 }
 
-/*
- * Attempt to flush the inode, this will actually fail
- * if the inode is pinned, but we dirty the inode again
- * at the point when it is unpinned after a log write,
- * since this is when the inode itself becomes flushable.
- */
+STATIC int
+xfs_log_inode(
+        struct xfs_inode        *ip)
+{
+        struct xfs_mount        *mp = ip->i_mount;
+        struct xfs_trans        *tp;
+        int                     error;
+
+        xfs_iunlock(ip, XFS_ILOCK_SHARED);
+        tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
+        error = xfs_trans_reserve(tp, 0, XFS_FSYNC_TS_LOG_RES(mp), 0, 0, 0);
+
+        if (error) {
+                xfs_trans_cancel(tp, 0);
+                /* we need to return with the lock hold shared */
+                xfs_ilock(ip, XFS_ILOCK_SHARED);
+                return error;
+        }
+
+        xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+        /*
+         * Note - it's possible that we might have pushed ourselves out of the
+         * way during trans_reserve which would flush the inode.  But there's
+         * no guarantee that the inode buffer has actually gone out yet (it's
+         * delwri).  Plus the buffer could be pinned anyway if it's part of
+         * an inode in another recent transaction.  So we play it safe and
+         * fire off the transaction anyway.
+         */
+        xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+        xfs_trans_ihold(tp, ip);
+        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+        xfs_trans_set_sync(tp);
+        error = xfs_trans_commit(tp, 0);
+        xfs_ilock_demote(ip, XFS_ILOCK_EXCL);
+
+        return error;
+}
+
 STATIC int
 xfs_fs_write_inode(
         struct inode            *inode,
@@ -1034,7 +1067,7 @@ xfs_fs_write_inode(
 {
         struct xfs_inode        *ip = XFS_I(inode);
         struct xfs_mount        *mp = ip->i_mount;
-        int                     error = 0;
+        int                     error = EAGAIN;
 
         xfs_itrace_entry(ip);
 
@@ -1045,35 +1078,55 @@ xfs_fs_write_inode(
                 error = xfs_wait_on_pages(ip, 0, -1);
                 if (error)
                         goto out;
-        }
-
-        /*
-         * Bypass inodes which have already been cleaned by
-         * the inode flush clustering code inside xfs_iflush
-         */
-        if (xfs_inode_clean(ip))
-                goto out;
 
-        /*
-         * We make this non-blocking if the inode is contended, return
-         * EAGAIN to indicate to the caller that they did not succeed.
-         * This prevents the flush path from blocking on inodes inside
-         * another operation right now, they get caught later by xfs_sync.
-         */
-        if (sync) {
+                /*
+                 * Make sure the inode has hit stable storage.  By using the
+                 * log and the fsync transactions we reduce the IOs we have
+                 * to do here from two (log and inode) to just the log.
+                 *
+                 * Note: We still need to do a delwri write of the inode after
+                 * this to flush it to the backing buffer so that bulkstat
+                 * works properly if this is the first time the inode has been
+                 * written.  Because we hold the ilock atomically over the
+                 * transaction commit and the inode flush we are guaranteed
+                 * that the inode is not pinned when it returns. If the flush
+                 * lock is already held, then the inode has already been
+                 * flushed once and we don't need to flush it again.  Hence
+                 * the code will only flush the inode if it isn't already
+                 * being flushed.
+                 */
                 xfs_ilock(ip, XFS_ILOCK_SHARED);
-                xfs_iflock(ip);
-
-                error = xfs_iflush(ip, SYNC_WAIT);
+                if (ip->i_update_core) {
+                        error = xfs_log_inode(ip);
+                        if (error)
+                                goto out_unlock;
+                }
         } else {
-                error = EAGAIN;
+                /*
+                 * We make this non-blocking if the inode is contended, return
+                 * EAGAIN to indicate to the caller that they did not succeed.
+                 * This prevents the flush path from blocking on inodes inside
+                 * another operation right now, they get caught later by xfs_sync.
+                 */
                 if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED))
                         goto out;
-                if (xfs_ipincount(ip) || !xfs_iflock_nowait(ip))
-                        goto out_unlock;
+        }
+
+        if (xfs_ipincount(ip) || !xfs_iflock_nowait(ip))
+                goto out_unlock;
 
-                error = xfs_iflush(ip, 0);
+        /*
+         * Now we have the flush lock and the inode is not pinned, we can check
+         * if the inode is really clean as we know that there are no pending
+         * transaction completions, it is not waiting on the delayed write
+         * queue and there is no IO in progress.
+         */
+        if (xfs_inode_clean(ip)) {
+                xfs_ifunlock(ip);
+                error = 0;
+                goto out_unlock;
         }
+        error = xfs_iflush(ip, 0);
 
  out_unlock:
         xfs_iunlock(ip, XFS_ILOCK_SHARED);