Merge branch 'master' of git://oss.sgi.com:8090/xfs/linux-2.6

1 files changed, 199 insertions, 302 deletions

diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index e229e9e001c2..bf4dc5eb4cfc 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -38,164 +38,122 @@
 #include "xfs_ialloc.h"
 #include "xfs_quota.h"
 #include "xfs_utils.h"
+#include "xfs_trans_priv.h"
+#include "xfs_inode_item.h"
 
 /*
- * Look up an inode by number in the given file system.
- * The inode is looked up in the cache held in each AG.
- * If the inode is found in the cache, attach it to the provided
- * vnode.
- *
- * If it is not in core, read it in from the file system's device,
- * add it to the cache and attach the provided vnode.
- *
- * The inode is locked according to the value of the lock_flags parameter.
- * This flag parameter indicates how and if the inode's IO lock and inode lock
- * should be taken.
- *
- * mp -- the mount point structure for the current file system.  It points
- *       to the inode hash table.
- * tp -- a pointer to the current transaction if there is one.  This is
- *       simply passed through to the xfs_iread() call.
- * ino -- the number of the inode desired.  This is the unique identifier
- *        within the file system for the inode being requested.
- * lock_flags -- flags indicating how to lock the inode.  See the comment
- *               for xfs_ilock() for a list of valid values.
- * bno -- the block number starting the buffer containing the inode,
- *        if known (as by bulkstat), else 0.
+ * Check the validity of the inode we just found it the cache
  */
-STATIC int
-xfs_iget_core(
-        struct inode    *inode,
-        xfs_mount_t     *mp,
-        xfs_trans_t     *tp,
-        xfs_ino_t       ino,
-        uint            flags,
-        uint            lock_flags,
-        xfs_inode_t     **ipp,
-        xfs_daddr_t     bno)
+static int
+xfs_iget_cache_hit(
+        struct xfs_perag        *pag,
+        struct xfs_inode        *ip,
+        int                     flags,
+        int                     lock_flags) __releases(pag->pag_ici_lock)
 {
-        struct inode    *old_inode;
-        xfs_inode_t     *ip;
-        xfs_inode_t     *iq;
-        int             error;
-        unsigned long   first_index, mask;
-        xfs_perag_t     *pag;
-        xfs_agino_t     agino;
+        struct xfs_mount        *mp = ip->i_mount;
+        int                     error = EAGAIN;
 
-        /* the radix tree exists only in inode capable AGs */
-        if (XFS_INO_TO_AGNO(mp, ino) >= mp->m_maxagi)
-                return EINVAL;
-
-        /* get the perag structure and ensure that it's inode capable */
-        pag = xfs_get_perag(mp, ino);
-        if (!pag->pagi_inodeok)
-                return EINVAL;
-        ASSERT(pag->pag_ici_init);
-        agino = XFS_INO_TO_AGINO(mp, ino);
+        /*
+         * If INEW is set this inode is being set up
+         * If IRECLAIM is set this inode is being torn down
+         * Pause and try again.
+         */
+        if (xfs_iflags_test(ip, (XFS_INEW|XFS_IRECLAIM))) {
+                XFS_STATS_INC(xs_ig_frecycle);
+                goto out_error;
+        }
 
-again:
-        read_lock(&pag->pag_ici_lock);
-        ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+        /* If IRECLAIMABLE is set, we've torn down the vfs inode part */
+        if (xfs_iflags_test(ip, XFS_IRECLAIMABLE)) {
 
-        if (ip != NULL) {
                 /*
-                 * If INEW is set this inode is being set up
-                 * we need to pause and try again.
+                 * If lookup is racing with unlink, then we should return an
+                 * error immediately so we don't remove it from the reclaim
+                 * list and potentially leak the inode.
                  */
-                if (xfs_iflags_test(ip, XFS_INEW)) {
-                        read_unlock(&pag->pag_ici_lock);
-                        delay(1);
-                        XFS_STATS_INC(xs_ig_frecycle);
-
-                        goto again;
+                if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
+                        error = ENOENT;
+                        goto out_error;
                 }
 
-                old_inode = ip->i_vnode;
-                if (old_inode == NULL) {
-                        /*
-                         * If IRECLAIM is set this inode is
-                         * on its way out of the system,
-                         * we need to pause and try again.
-                         */
-                        if (xfs_iflags_test(ip, XFS_IRECLAIM)) {
-                                read_unlock(&pag->pag_ici_lock);
-                                delay(1);
-                                XFS_STATS_INC(xs_ig_frecycle);
-
-                                goto again;
-                        }
-                        ASSERT(xfs_iflags_test(ip, XFS_IRECLAIMABLE));
-
-                        /*
-                         * If lookup is racing with unlink, then we
-                         * should return an error immediately so we
-                         * don't remove it from the reclaim list and
-                         * potentially leak the inode.
-                         */
-                        if ((ip->i_d.di_mode == 0) &&
-                            !(flags & XFS_IGET_CREATE)) {
-                                read_unlock(&pag->pag_ici_lock);
-                                xfs_put_perag(mp, pag);
-                                return ENOENT;
-                        }
-
-                        xfs_itrace_exit_tag(ip, "xfs_iget.alloc");
-
-                        XFS_STATS_INC(xs_ig_found);
-                        xfs_iflags_clear(ip, XFS_IRECLAIMABLE);
-                        read_unlock(&pag->pag_ici_lock);
-
-                        XFS_MOUNT_ILOCK(mp);
-                        list_del_init(&ip->i_reclaim);
-                        XFS_MOUNT_IUNLOCK(mp);
-
-                        goto finish_inode;
-
-                } else if (inode != old_inode) {
-                        /* The inode is being torn down, pause and
-                         * try again.
-                         */
-                        if (old_inode->i_state & (I_FREEING | I_CLEAR)) {
-                                read_unlock(&pag->pag_ici_lock);
-                                delay(1);
-                                XFS_STATS_INC(xs_ig_frecycle);
-
-                                goto again;
-                        }
-/* Chances are the other vnode (the one in the inode) is being torn
-* down right now, and we landed on top of it. Question is, what do
-* we do? Unhook the old inode and hook up the new one?
-*/
-                        cmn_err(CE_PANIC,
-                "xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p",
-                                        old_inode, inode);
-                }
+                xfs_itrace_exit_tag(ip, "xfs_iget.alloc");
 
                 /*
-                 * Inode cache hit
+                 * We need to re-initialise the VFS inode as it has been
+                 * 'freed' by the VFS. Do this here so we can deal with
+                 * errors cleanly, then tag it so it can be set up correctly
+                 * later.
                  */
-                read_unlock(&pag->pag_ici_lock);
-                XFS_STATS_INC(xs_ig_found);
-
-finish_inode:
-                if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
-                        xfs_put_perag(mp, pag);
-                        return ENOENT;
+                if (!inode_init_always(mp->m_super, VFS_I(ip))) {
+                        error = ENOMEM;
+                        goto out_error;
                 }
 
-                if (lock_flags != 0)
-                        xfs_ilock(ip, lock_flags);
+                /*
+                 * We must set the XFS_INEW flag before clearing the
+                 * XFS_IRECLAIMABLE flag so that if a racing lookup does
+                 * not find the XFS_IRECLAIMABLE above but has the igrab()
+                 * below succeed we can safely check XFS_INEW to detect
+                 * that this inode is still being initialised.
+                 */
+                xfs_iflags_set(ip, XFS_INEW);
+                xfs_iflags_clear(ip, XFS_IRECLAIMABLE);
+
+                /* clear the radix tree reclaim flag as well. */
+                __xfs_inode_clear_reclaim_tag(mp, pag, ip);
+        } else if (!igrab(VFS_I(ip))) {
+                /* If the VFS inode is being torn down, pause and try again. */
+                XFS_STATS_INC(xs_ig_frecycle);
+                goto out_error;
+        } else if (xfs_iflags_test(ip, XFS_INEW)) {
+                /*
+                 * We are racing with another cache hit that is
+                 * currently recycling this inode out of the XFS_IRECLAIMABLE
+                 * state. Wait for the initialisation to complete before
+                 * continuing.
+                 */
+                wait_on_inode(VFS_I(ip));
+        }
 
-                xfs_iflags_clear(ip, XFS_ISTALE);
-                xfs_itrace_exit_tag(ip, "xfs_iget.found");
-                goto return_ip;
+        if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
+                error = ENOENT;
+                iput(VFS_I(ip));
+                goto out_error;
         }
 
-        /*
-         * Inode cache miss
-         */
+        /* We've got a live one. */
+        read_unlock(&pag->pag_ici_lock);
+
+        if (lock_flags != 0)
+                xfs_ilock(ip, lock_flags);
+
+        xfs_iflags_clear(ip, XFS_ISTALE);
+        xfs_itrace_exit_tag(ip, "xfs_iget.found");
+        XFS_STATS_INC(xs_ig_found);
+        return 0;
+
+out_error:
         read_unlock(&pag->pag_ici_lock);
-        XFS_STATS_INC(xs_ig_missed);
+        return error;
+}
+
+
+static int
+xfs_iget_cache_miss(
+        struct xfs_mount        *mp,
+        struct xfs_perag        *pag,
+        xfs_trans_t             *tp,
+        xfs_ino_t               ino,
+        struct xfs_inode        **ipp,
+        xfs_daddr_t             bno,
+        int                     flags,
+        int                     lock_flags) __releases(pag->pag_ici_lock)
+{
+        struct xfs_inode        *ip;
+        int                     error;
+        unsigned long           first_index, mask;
+        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ino);
 
         /*
          * Read the disk inode attributes into a new inode structure and get
@@ -203,116 +161,85 @@ finish_inode:
          */
         error = xfs_iread(mp, tp, ino, &ip, bno,
                           (flags & XFS_IGET_BULKSTAT) ? XFS_IMAP_BULKSTAT : 0);
-        if (error) {
-                xfs_put_perag(mp, pag);
+        if (error)
                 return error;
-        }
 
         xfs_itrace_exit_tag(ip, "xfs_iget.alloc");
 
-
-        mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
-                     "xfsino", ip->i_ino);
-        mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
-        init_waitqueue_head(&ip->i_ipin_wait);
-        atomic_set(&ip->i_pincount, 0);
-
-        /*
-         * Because we want to use a counting completion, complete
-         * the flush completion once to allow a single access to
-         * the flush completion without blocking.
-         */
-        init_completion(&ip->i_flush);
-        complete(&ip->i_flush);
+        if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
+                error = ENOENT;
+                goto out_destroy;
+        }
 
         if (lock_flags)
                 xfs_ilock(ip, lock_flags);
 
-        if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
-                xfs_idestroy(ip);
-                xfs_put_perag(mp, pag);
-                return ENOENT;
-        }
-
         /*
          * Preload the radix tree so we can insert safely under the
-         * write spinlock.
+         * write spinlock. Note that we cannot sleep inside the preload
+         * region.
          */
         if (radix_tree_preload(GFP_KERNEL)) {
-                xfs_idestroy(ip);
-                delay(1);
-                goto again;
+                error = EAGAIN;
+                goto out_unlock;
         }
+
         mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
         first_index = agino & mask;
         write_lock(&pag->pag_ici_lock);
-        /*
-         * insert the new inode
-         */
+
+        /* insert the new inode */
         error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
         if (unlikely(error)) {
-                BUG_ON(error != -EEXIST);
-                write_unlock(&pag->pag_ici_lock);
-                radix_tree_preload_end();
-                xfs_idestroy(ip);
+                WARN_ON(error != -EEXIST);
                 XFS_STATS_INC(xs_ig_dup);
-                goto again;
+                error = EAGAIN;
+                goto out_preload_end;
         }
 
-        /*
-         * These values _must_ be set before releasing the radix tree lock!
-         */
+        /* These values _must_ be set before releasing the radix tree lock! */
         ip->i_udquot = ip->i_gdquot = NULL;
         xfs_iflags_set(ip, XFS_INEW);
 
         write_unlock(&pag->pag_ici_lock);
         radix_tree_preload_end();
-
-        /*
-         * Link ip to its mount and thread it on the mount's inode list.
-         */
-        XFS_MOUNT_ILOCK(mp);
-        if ((iq = mp->m_inodes)) {
-                ASSERT(iq->i_mprev->i_mnext == iq);
-                ip->i_mprev = iq->i_mprev;
-                iq->i_mprev->i_mnext = ip;
-                iq->i_mprev = ip;
-                ip->i_mnext = iq;
-        } else {
-                ip->i_mnext = ip;
-                ip->i_mprev = ip;
-        }
-        mp->m_inodes = ip;
-
-        XFS_MOUNT_IUNLOCK(mp);
-        xfs_put_perag(mp, pag);
-
- return_ip:
-        ASSERT(ip->i_df.if_ext_max ==
-               XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));
-
-        xfs_iflags_set(ip, XFS_IMODIFIED);
         *ipp = ip;
-
-        /*
-         * Set up the Linux with the Linux inode.
-         */
-        ip->i_vnode = inode;
-        inode->i_private = ip;
-
-        /*
-         * If we have a real type for an on-disk inode, we can set ops(&unlock)
-         * now.  If it's a new inode being created, xfs_ialloc will handle it.
-         */
-        if (ip->i_d.di_mode != 0)
-                xfs_setup_inode(ip);
         return 0;
-}
 
+out_preload_end:
+        write_unlock(&pag->pag_ici_lock);
+        radix_tree_preload_end();
+out_unlock:
+        if (lock_flags)
+                xfs_iunlock(ip, lock_flags);
+out_destroy:
+        xfs_destroy_inode(ip);
+        return error;
+}
 
 /*
- * The 'normal' internal xfs_iget, if needed it will
- * 'allocate', or 'get', the vnode.
+ * Look up an inode by number in the given file system.
+ * The inode is looked up in the cache held in each AG.
+ * If the inode is found in the cache, initialise the vfs inode
+ * if necessary.
+ *
+ * If it is not in core, read it in from the file system's device,
+ * add it to the cache and initialise the vfs inode.
+ *
+ * The inode is locked according to the value of the lock_flags parameter.
+ * This flag parameter indicates how and if the inode's IO lock and inode lock
+ * should be taken.
+ *
+ * mp -- the mount point structure for the current file system.  It points
+ *       to the inode hash table.
+ * tp -- a pointer to the current transaction if there is one.  This is
+ *       simply passed through to the xfs_iread() call.
+ * ino -- the number of the inode desired.  This is the unique identifier
+ *        within the file system for the inode being requested.
+ * lock_flags -- flags indicating how to lock the inode.  See the comment
+ *               for xfs_ilock() for a list of valid values.
+ * bno -- the block number starting the buffer containing the inode,
+ *        if known (as by bulkstat), else 0.
  */
 int
 xfs_iget(
@@ -324,61 +251,65 @@ xfs_iget(
         xfs_inode_t     **ipp,
         xfs_daddr_t     bno)
 {
-        struct inode    *inode;
         xfs_inode_t     *ip;
         int             error;
+        xfs_perag_t     *pag;
+        xfs_agino_t     agino;
 
-        XFS_STATS_INC(xs_ig_attempts);
-
-retry:
-        inode = iget_locked(mp->m_super, ino);
-        if (!inode)
-                /* If we got no inode we are out of memory */
-                return ENOMEM;
-
-        if (inode->i_state & I_NEW) {
-                XFS_STATS_INC(vn_active);
-                XFS_STATS_INC(vn_alloc);
-
-                error = xfs_iget_core(inode, mp, tp, ino, flags,
-                                lock_flags, ipp, bno);
-                if (error) {
-                        make_bad_inode(inode);
-                        if (inode->i_state & I_NEW)
-                                unlock_new_inode(inode);
-                        iput(inode);
-                }
-                return error;
+        /* the radix tree exists only in inode capable AGs */
+        if (XFS_INO_TO_AGNO(mp, ino) >= mp->m_maxagi)
+                return EINVAL;
+
+        /* get the perag structure and ensure that it's inode capable */
+        pag = xfs_get_perag(mp, ino);
+        if (!pag->pagi_inodeok)
+                return EINVAL;
+        ASSERT(pag->pag_ici_init);
+        agino = XFS_INO_TO_AGINO(mp, ino);
+
+again:
+        error = 0;
+        read_lock(&pag->pag_ici_lock);
+        ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+
+        if (ip) {
+                error = xfs_iget_cache_hit(pag, ip, flags, lock_flags);
+                if (error)
+                        goto out_error_or_again;
+        } else {
+                read_unlock(&pag->pag_ici_lock);
+                XFS_STATS_INC(xs_ig_missed);
+
+                error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip, bno,
+                                                        flags, lock_flags);
+                if (error)
+                        goto out_error_or_again;
         }
+        xfs_put_perag(mp, pag);
+
+        xfs_iflags_set(ip, XFS_IMODIFIED);
+        *ipp = ip;
 
+        ASSERT(ip->i_df.if_ext_max ==
+               XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));
         /*
-         * If the inode is not fully constructed due to
-         * filehandle mismatches wait for the inode to go
-         * away and try again.
-         *
-         * iget_locked will call __wait_on_freeing_inode
-         * to wait for the inode to go away.
+         * If we have a real type for an on-disk inode, we can set ops(&unlock)
+         * now.  If it's a new inode being created, xfs_ialloc will handle it.
          */
-        if (is_bad_inode(inode)) {
-                iput(inode);
-                delay(1);
-                goto retry;
-        }
+        if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)
+                xfs_setup_inode(ip);
+        return 0;
 
-        ip = XFS_I(inode);
-        if (!ip) {
-                iput(inode);
+out_error_or_again:
+        if (error == EAGAIN) {
                 delay(1);
-                goto retry;
+                goto again;
         }
-
-        if (lock_flags != 0)
-                xfs_ilock(ip, lock_flags);
-        XFS_STATS_INC(xs_ig_found);
-        *ipp = ip;
-        return 0;
+        xfs_put_perag(mp, pag);
+        return error;
 }
 
+
 /*
  * Look for the inode corresponding to the given ino in the hash table.
  * If it is there and its i_transp pointer matches tp, return it.
@@ -462,14 +393,13 @@ xfs_ireclaim(xfs_inode_t *ip)
         xfs_iextract(ip);
 
         /*
-         * Here we do a spurious inode lock in order to coordinate with
-         * xfs_sync().  This is because xfs_sync() references the inodes
-         * in the mount list without taking references on the corresponding
-         * vnodes.  We make that OK here by ensuring that we wait until
-         * the inode is unlocked in xfs_sync() before we go ahead and
-         * free it.  We get both the regular lock and the io lock because
-         * the xfs_sync() code may need to drop the regular one but will
-         * still hold the io lock.
+         * Here we do a spurious inode lock in order to coordinate with inode
+         * cache radix tree lookups.  This is because the lookup can reference
+         * the inodes in the cache without taking references.  We make that OK
+         * here by ensuring that we wait until the inode is unlocked after the
+         * lookup before we go ahead and free it.  We get both the ilock and
+         * the iolock because the code may need to drop the ilock one but will
+         * still hold the iolock.
          */
         xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 
@@ -480,14 +410,6 @@ xfs_ireclaim(xfs_inode_t *ip)
         XFS_QM_DQDETACH(ip->i_mount, ip);
 
         /*
-         * Pull our behavior descriptor from the vnode chain.
-         */
-        if (ip->i_vnode) {
-                ip->i_vnode->i_private = NULL;
-                ip->i_vnode = NULL;
-        }
-
-        /*
          * Free all memory associated with the inode.
          */
         xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
@@ -505,38 +427,13 @@ xfs_iextract(
 {
         xfs_mount_t     *mp = ip->i_mount;
         xfs_perag_t     *pag = xfs_get_perag(mp, ip->i_ino);
-        xfs_inode_t     *iq;
 
         write_lock(&pag->pag_ici_lock);
         radix_tree_delete(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino));
         write_unlock(&pag->pag_ici_lock);
         xfs_put_perag(mp, pag);
 
-        /*
-         * Remove from mount's inode list.
-         */
-        XFS_MOUNT_ILOCK(mp);
-        ASSERT((ip->i_mnext != NULL) && (ip->i_mprev != NULL));
-        iq = ip->i_mnext;
-        iq->i_mprev = ip->i_mprev;
-        ip->i_mprev->i_mnext = iq;
-
-        /*
-         * Fix up the head pointer if it points to the inode being deleted.
-         */
-        if (mp->m_inodes == ip) {
-                if (ip == iq) {
-                        mp->m_inodes = NULL;
-                } else {
-                        mp->m_inodes = iq;
-                }
-        }
-
-        /* Deal with the deleted inodes list */
-        list_del_init(&ip->i_reclaim);
-
         mp->m_ireclaims++;
-        XFS_MOUNT_IUNLOCK(mp);
 }
 
 /*
@@ -737,7 +634,7 @@ xfs_iunlock(
                  * it is in the AIL and anyone is waiting on it.  Don't do
                  * this if the caller has asked us not to.
                  */
-                xfs_trans_unlocked_item(ip->i_mount,
+                xfs_trans_unlocked_item(ip->i_itemp->ili_item.li_ailp,
                                         (xfs_log_item_t*)(ip->i_itemp));
         }
         xfs_ilock_trace(ip, 3, lock_flags, (inst_t *)__return_address);