[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>

4 files changed, 37 insertions, 43 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)
diff --git a/fs/xfs/linux-2.6/xfs_vnode.c b/fs/xfs/linux-2.6/xfs_vnode.c
index b52528bbbfff..dceb6dbaa2da 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.c
+++ b/fs/xfs/linux-2.6/xfs_vnode.c
@@ -90,10 +90,10 @@ vn_ioerror(
  */
 static inline int xfs_icount(struct xfs_inode *ip)
 {
-        struct inode *vp = VFS_I(ip);
+        struct inode *inode = VFS_I(ip);
 
-        if (vp)
-                return vn_count(vp);
+        if (!inode)
+                return atomic_read(&inode->i_count);
         return -1;
 }
 
diff --git a/fs/xfs/linux-2.6/xfs_vnode.h b/fs/xfs/linux-2.6/xfs_vnode.h
index 683ce16210ff..bf89e41c3b8d 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.h
+++ b/fs/xfs/linux-2.6/xfs_vnode.h
@@ -80,11 +80,6 @@ do { \
         iput(VFS_I(ip)); \
 } while (0)
 
-static inline struct inode *vn_grab(struct inode *vp)
-{
-        return igrab(vp);
-}
-
 /*
  * Dealing with bad inodes
  */
diff --git a/fs/xfs/quota/xfs_qm_syscalls.c b/fs/xfs/quota/xfs_qm_syscalls.c
index 26152b9ccc6f..4254b074223b 100644
--- a/fs/xfs/quota/xfs_qm_syscalls.c
+++ b/fs/xfs/quota/xfs_qm_syscalls.c
@@ -1031,13 +1031,13 @@ xfs_qm_dqrele_inodes_ag(
         uint            flags)
 {
         xfs_inode_t     *ip = NULL;
-        struct inode    *vp = NULL;
         xfs_perag_t     *pag = &mp->m_perag[ag];
         int             first_index = 0;
         int             nr_found;
 
         do {
-                boolean_t       vnode_refd = B_FALSE;
+                boolean_t       inode_refed;
+                struct inode    *inode;
 
                 /*
                  * use a gang lookup to find the next inode in the tree
@@ -1057,19 +1057,19 @@ xfs_qm_dqrele_inodes_ag(
                 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
 
                 /* skip quota inodes and those in reclaim */
-                vp = VFS_I(ip);
-                if (!vp || ip == XFS_QI_UQIP(mp) || ip == XFS_QI_GQIP(mp)) {
+                inode = VFS_I(ip);
+                if (!inode || ip == XFS_QI_UQIP(mp) || ip == XFS_QI_GQIP(mp)) {
                         ASSERT(ip->i_udquot == NULL);
                         ASSERT(ip->i_gdquot == NULL);
                         read_unlock(&pag->pag_ici_lock);
                         continue;
                 }
                 if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL) == 0) {
-                        vp = vn_grab(vp);
+                        inode = igrab(inode);
                         read_unlock(&pag->pag_ici_lock);
-                        if (!vp)
+                        if (!inode)
                                 continue;
-                        vnode_refd = B_TRUE;
+                        inode_refed = B_TRUE;
                         xfs_ilock(ip, XFS_ILOCK_EXCL);
                 } else {
                         read_unlock(&pag->pag_ici_lock);
@@ -1084,7 +1084,7 @@ xfs_qm_dqrele_inodes_ag(
                         ip->i_gdquot = NULL;
                 }
                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
-                if (vnode_refd)
+                if (inode_refed)
                         IRELE(ip);
         } while (nr_found);
 }