[PATCH 02/10] XFS: Use struct inodes instead of vnodes to kill vn_grab

Dave Chinner
2008-09-13T13:56:09Z

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.

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/linux-2.6/xfs_sync.c | 53 +++++++++++++++++++--------------------
fs/xfs/linux-2.6/xfs_vnode.c | 6 ++--
fs/xfs/linux-2.6/xfs_vnode.h | 5 ----
fs/xfs/quota/xfs_qm_syscalls.c | 16 ++++++------
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 59da332..461c1dc 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 b52528b..dceb6db 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 683ce16..bf89e41 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 26152b9..4254b07 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);
}
--
1.5.6