[XFS] Use struct inodes instead of vnodes to kill vn_grab

With the sync code relocated to the linux-2.6 directory we can use struct
inodes directly. If we do the same thing for the quota release code, we
can remove vn_grab altogether. While here, convert the VN_BAD() checks to
is_bad_inode() so we can remove vnodes entirely from this code.

SGI-PV: 988140

SGI-Modid: xfs-linux-melb:xfs-kern:32304a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

1 files changed, 26 insertions, 27 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 59da3327a6b5..461c1dc35d37 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -131,10 +131,7 @@ xfs_sync_inodes_ag(
         int             flags,
         int             *bypassed)
 {
-        xfs_inode_t     *ip = NULL;
-        struct inode    *vp = NULL;
         xfs_perag_t     *pag = &mp->m_perag[ag];
-        boolean_t       vnode_refed = B_FALSE;
         int             nr_found;
         int             first_index = 0;
         int             error = 0;
@@ -156,6 +153,10 @@ xfs_sync_inodes_ag(
         }
 
         do {
+                struct inode    *inode;
+                boolean_t       inode_refed;
+                xfs_inode_t     *ip = NULL;
+
                 /*
                  * use a gang lookup to find the next inode in the tree
                  * as the tree is sparse and a gang lookup walks to find
@@ -177,14 +178,14 @@ xfs_sync_inodes_ag(
                  * skip inodes in reclaim. Let xfs_syncsub do that for
                  * us so we don't need to worry.
                  */
-                vp = VFS_I(ip);
-                if (!vp) {
+                if (xfs_iflags_test(ip, (XFS_IRECLAIM|XFS_IRECLAIMABLE))) {
                         read_unlock(&pag->pag_ici_lock);
                         continue;
                 }
 
                 /* bad inodes are dealt with elsewhere */
-                if (VN_BAD(vp)) {
+                inode = VFS_I(ip);
+                if (is_bad_inode(inode)) {
                         read_unlock(&pag->pag_ici_lock);
                         continue;
                 }
@@ -196,30 +197,29 @@ xfs_sync_inodes_ag(
                 }
 
                 /*
-                 * The inode lock here actually coordinates with the almost
-                 * spurious inode lock in xfs_ireclaim() to prevent the vnode
-                 * we handle here without a reference from being freed while we
-                 * reference it.  If we lock the inode while it's on the mount
-                 * list here, then the spurious inode lock in xfs_ireclaim()
-                 * after the inode is pulled from the mount list will sleep
-                 * until we release it here.  This keeps the vnode from being
-                 * freed while we reference it.
+                 * If we can't get a reference on the VFS_I, the inode must be
+                 * in reclaim. If we can get the inode lock without blocking,
+                 * it is safe to flush the inode because we hold the tree lock
+                 * and xfs_iextract will block right now. Hence if we lock the
+                 * inode while holding the tree lock, xfs_ireclaim() is
+                 * guaranteed to block on the inode lock we now hold and hence
+                 * it is safe to reference the inode until we drop the inode
+                 * locks completely.
                  */
-                if (xfs_ilock_nowait(ip, lock_flags) == 0) {
-                        vp = vn_grab(vp);
+                inode_refed = B_FALSE;
+                if (igrab(inode)) {
                         read_unlock(&pag->pag_ici_lock);
-                        if (!vp)
-                                continue;
                         xfs_ilock(ip, lock_flags);
-
-                        ASSERT(vp == VFS_I(ip));
-                        ASSERT(ip->i_mount == mp);
-
-                        vnode_refed = B_TRUE;
+                        inode_refed = B_TRUE;
                 } else {
-                        /* safe to unlock here as we have a reference */
+                        if (!xfs_ilock_nowait(ip, lock_flags)) {
+                                /* leave it to reclaim */
+                                read_unlock(&pag->pag_ici_lock);
+                                continue;
+                        }
                         read_unlock(&pag->pag_ici_lock);
                 }
+
                 /*
                  * If we have to flush data or wait for I/O completion
                  * we need to drop the ilock that we currently hold.
@@ -240,7 +240,7 @@ xfs_sync_inodes_ag(
                         xfs_ilock(ip, XFS_ILOCK_SHARED);
                 }
 
-                if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
+                if ((flags & SYNC_DELWRI) && VN_DIRTY(inode)) {
                         xfs_iunlock(ip, XFS_ILOCK_SHARED);
                         error = xfs_flush_pages(ip, 0, -1, fflag, FI_NONE);
                         if (flags & SYNC_IOWAIT)
@@ -268,9 +268,8 @@ xfs_sync_inodes_ag(
                 if (lock_flags)
                         xfs_iunlock(ip, lock_flags);
 
-                if (vnode_refed) {
+                if (inode_refed) {
                         IRELE(ip);
-                        vnode_refed = B_FALSE;
                 }
 
                 if (error)