xfs: remove xfs_iget.c

The inode cache functions remaining in xfs_iget.c can be moved to xfs_icache.c
along with the other inode cache functions. This removes all functionality from
xfs_iget.c, so the file can simply be removed.

This move results in various functions now only having the scope of a single
file (e.g. xfs_inode_free()), so clean up all the definitions and exported
prototypes in xfs_icache.[ch] and xfs_inode.h appropriately.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 418 insertions, 3 deletions

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index eba216f11d5e..9c8703b5cd72 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -41,6 +41,421 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 
+STATIC void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp,
+                                struct xfs_perag *pag, struct xfs_inode *ip);
+
+/*
+ * Allocate and initialise an xfs_inode.
+ */
+STATIC struct xfs_inode *
+xfs_inode_alloc(
+        struct xfs_mount        *mp,
+        xfs_ino_t               ino)
+{
+        struct xfs_inode        *ip;
+
+        /*
+         * if this didn't occur in transactions, we could use
+         * KM_MAYFAIL and return NULL here on ENOMEM. Set the
+         * code up to do this anyway.
+         */
+        ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
+        if (!ip)
+                return NULL;
+        if (inode_init_always(mp->m_super, VFS_I(ip))) {
+                kmem_zone_free(xfs_inode_zone, ip);
+                return NULL;
+        }
+
+        ASSERT(atomic_read(&ip->i_pincount) == 0);
+        ASSERT(!spin_is_locked(&ip->i_flags_lock));
+        ASSERT(!xfs_isiflocked(ip));
+        ASSERT(ip->i_ino == 0);
+
+        mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+
+        /* initialise the xfs inode */
+        ip->i_ino = ino;
+        ip->i_mount = mp;
+        memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
+        ip->i_afp = NULL;
+        memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
+        ip->i_flags = 0;
+        ip->i_delayed_blks = 0;
+        memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
+
+        return ip;
+}
+
+STATIC void
+xfs_inode_free_callback(
+        struct rcu_head         *head)
+{
+        struct inode            *inode = container_of(head, struct inode, i_rcu);
+        struct xfs_inode        *ip = XFS_I(inode);
+
+        kmem_zone_free(xfs_inode_zone, ip);
+}
+
+STATIC void
+xfs_inode_free(
+        struct xfs_inode        *ip)
+{
+        switch (ip->i_d.di_mode & S_IFMT) {
+        case S_IFREG:
+        case S_IFDIR:
+        case S_IFLNK:
+                xfs_idestroy_fork(ip, XFS_DATA_FORK);
+                break;
+        }
+
+        if (ip->i_afp)
+                xfs_idestroy_fork(ip, XFS_ATTR_FORK);
+
+        if (ip->i_itemp) {
+                ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL));
+                xfs_inode_item_destroy(ip);
+                ip->i_itemp = NULL;
+        }
+
+        /* asserts to verify all state is correct here */
+        ASSERT(atomic_read(&ip->i_pincount) == 0);
+        ASSERT(!spin_is_locked(&ip->i_flags_lock));
+        ASSERT(!xfs_isiflocked(ip));
+
+        /*
+         * Because we use RCU freeing we need to ensure the inode always
+         * appears to be reclaimed with an invalid inode number when in the
+         * free state. The ip->i_flags_lock provides the barrier against lookup
+         * races.
+         */
+        spin_lock(&ip->i_flags_lock);
+        ip->i_flags = XFS_IRECLAIM;
+        ip->i_ino = 0;
+        spin_unlock(&ip->i_flags_lock);
+
+        call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
+}
+
+/*
+ * Check the validity of the inode we just found it the cache
+ */
+static int
+xfs_iget_cache_hit(
+        struct xfs_perag        *pag,
+        struct xfs_inode        *ip,
+        xfs_ino_t               ino,
+        int                     flags,
+        int                     lock_flags) __releases(RCU)
+{
+        struct inode            *inode = VFS_I(ip);
+        struct xfs_mount        *mp = ip->i_mount;
+        int                     error;
+
+        /*
+         * check for re-use of an inode within an RCU grace period due to the
+         * radix tree nodes not being updated yet. We monitor for this by
+         * setting the inode number to zero before freeing the inode structure.
+         * If the inode has been reallocated and set up, then the inode number
+         * will not match, so check for that, too.
+         */
+        spin_lock(&ip->i_flags_lock);
+        if (ip->i_ino != ino) {
+                trace_xfs_iget_skip(ip);
+                XFS_STATS_INC(xs_ig_frecycle);
+                error = EAGAIN;
+                goto out_error;
+        }
+
+
+        /*
+         * If we are racing with another cache hit that is currently
+         * instantiating this inode or currently recycling it out of
+         * reclaimabe state, wait for the initialisation to complete
+         * before continuing.
+         *
+         * XXX(hch): eventually we should do something equivalent to
+         *           wait_on_inode to wait for these flags to be cleared
+         *           instead of polling for it.
+         */
+        if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
+                trace_xfs_iget_skip(ip);
+                XFS_STATS_INC(xs_ig_frecycle);
+                error = EAGAIN;
+                goto out_error;
+        }
+
+        /*
+         * If lookup is racing with unlink return an error immediately.
+         */
+        if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
+                error = ENOENT;
+                goto out_error;
+        }
+
+        /*
+         * If IRECLAIMABLE is set, we've torn down the VFS inode already.
+         * Need to carefully get it back into useable state.
+         */
+        if (ip->i_flags & XFS_IRECLAIMABLE) {
+                trace_xfs_iget_reclaim(ip);
+
+                /*
+                 * We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
+                 * from stomping over us while we recycle the inode.  We can't
+                 * clear the radix tree reclaimable tag yet as it requires
+                 * pag_ici_lock to be held exclusive.
+                 */
+                ip->i_flags |= XFS_IRECLAIM;
+
+                spin_unlock(&ip->i_flags_lock);
+                rcu_read_unlock();
+
+                error = -inode_init_always(mp->m_super, inode);
+                if (error) {
+                        /*
+                         * Re-initializing the inode failed, and we are in deep
+                         * trouble.  Try to re-add it to the reclaim list.
+                         */
+                        rcu_read_lock();
+                        spin_lock(&ip->i_flags_lock);
+
+                        ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
+                        ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
+                        trace_xfs_iget_reclaim_fail(ip);
+                        goto out_error;
+                }
+
+                spin_lock(&pag->pag_ici_lock);
+                spin_lock(&ip->i_flags_lock);
+
+                /*
+                 * Clear the per-lifetime state in the inode as we are now
+                 * effectively a new inode and need to return to the initial
+                 * state before reuse occurs.
+                 */
+                ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
+                ip->i_flags |= XFS_INEW;
+                __xfs_inode_clear_reclaim_tag(mp, pag, ip);
+                inode->i_state = I_NEW;
+
+                ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
+                mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
+
+                spin_unlock(&ip->i_flags_lock);
+                spin_unlock(&pag->pag_ici_lock);
+        } else {
+                /* If the VFS inode is being torn down, pause and try again. */
+                if (!igrab(inode)) {
+                        trace_xfs_iget_skip(ip);
+                        error = EAGAIN;
+                        goto out_error;
+                }
+
+                /* We've got a live one. */
+                spin_unlock(&ip->i_flags_lock);
+                rcu_read_unlock();
+                trace_xfs_iget_hit(ip);
+        }
+
+        if (lock_flags != 0)
+                xfs_ilock(ip, lock_flags);
+
+        xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
+        XFS_STATS_INC(xs_ig_found);
+
+        return 0;
+
+out_error:
+        spin_unlock(&ip->i_flags_lock);
+        rcu_read_unlock();
+        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,
+        int                     flags,
+        int                     lock_flags)
+{
+        struct xfs_inode        *ip;
+        int                     error;
+        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ino);
+        int                     iflags;
+
+        ip = xfs_inode_alloc(mp, ino);
+        if (!ip)
+                return ENOMEM;
+
+        error = xfs_iread(mp, tp, ip, flags);
+        if (error)
+                goto out_destroy;
+
+        trace_xfs_iget_miss(ip);
+
+        if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
+                error = ENOENT;
+                goto out_destroy;
+        }
+
+        /*
+         * Preload the radix tree so we can insert safely under the
+         * write spinlock. Note that we cannot sleep inside the preload
+         * region. Since we can be called from transaction context, don't
+         * recurse into the file system.
+         */
+        if (radix_tree_preload(GFP_NOFS)) {
+                error = EAGAIN;
+                goto out_destroy;
+        }
+
+        /*
+         * Because the inode hasn't been added to the radix-tree yet it can't
+         * be found by another thread, so we can do the non-sleeping lock here.
+         */
+        if (lock_flags) {
+                if (!xfs_ilock_nowait(ip, lock_flags))
+                        BUG();
+        }
+
+        /*
+         * These values must be set before inserting the inode into the radix
+         * tree as the moment it is inserted a concurrent lookup (allowed by the
+         * RCU locking mechanism) can find it and that lookup must see that this
+         * is an inode currently under construction (i.e. that XFS_INEW is set).
+         * The ip->i_flags_lock that protects the XFS_INEW flag forms the
+         * memory barrier that ensures this detection works correctly at lookup
+         * time.
+         */
+        iflags = XFS_INEW;
+        if (flags & XFS_IGET_DONTCACHE)
+                iflags |= XFS_IDONTCACHE;
+        ip->i_udquot = ip->i_gdquot = NULL;
+        xfs_iflags_set(ip, iflags);
+
+        /* insert the new inode */
+        spin_lock(&pag->pag_ici_lock);
+        error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
+        if (unlikely(error)) {
+                WARN_ON(error != -EEXIST);
+                XFS_STATS_INC(xs_ig_dup);
+                error = EAGAIN;
+                goto out_preload_end;
+        }
+        spin_unlock(&pag->pag_ici_lock);
+        radix_tree_preload_end();
+
+        *ipp = ip;
+        return 0;
+
+out_preload_end:
+        spin_unlock(&pag->pag_ici_lock);
+        radix_tree_preload_end();
+        if (lock_flags)
+                xfs_iunlock(ip, lock_flags);
+out_destroy:
+        __destroy_inode(VFS_I(ip));
+        xfs_inode_free(ip);
+        return error;
+}
+
+/*
+ * 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.
+ */
+int
+xfs_iget(
+        xfs_mount_t     *mp,
+        xfs_trans_t     *tp,
+        xfs_ino_t       ino,
+        uint            flags,
+        uint            lock_flags,
+        xfs_inode_t     **ipp)
+{
+        xfs_inode_t     *ip;
+        int             error;
+        xfs_perag_t     *pag;
+        xfs_agino_t     agino;
+
+        /*
+         * xfs_reclaim_inode() uses the ILOCK to ensure an inode
+         * doesn't get freed while it's being referenced during a
+         * radix tree traversal here.  It assumes this function
+         * aqcuires only the ILOCK (and therefore it has no need to
+         * involve the IOLOCK in this synchronization).
+         */
+        ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
+
+        /* reject inode numbers outside existing AGs */
+        if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
+                return EINVAL;
+
+        /* get the perag structure and ensure that it's inode capable */
+        pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
+        agino = XFS_INO_TO_AGINO(mp, ino);
+
+again:
+        error = 0;
+        rcu_read_lock();
+        ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+
+        if (ip) {
+                error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
+                if (error)
+                        goto out_error_or_again;
+        } else {
+                rcu_read_unlock();
+                XFS_STATS_INC(xs_ig_missed);
+
+                error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
+                                                        flags, lock_flags);
+                if (error)
+                        goto out_error_or_again;
+        }
+        xfs_perag_put(pag);
+
+        *ipp = 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 (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)
+                xfs_setup_inode(ip);
+        return 0;
+
+out_error_or_again:
+        if (error == EAGAIN) {
+                delay(1);
+                goto again;
+        }
+        xfs_perag_put(pag);
+        return error;
+}
+
 /*
  * The inode lookup is done in batches to keep the amount of lock traffic and
  * radix tree lookups to a minimum. The batch size is a trade off between
@@ -253,7 +668,7 @@ xfs_reclaim_worker(
         xfs_reclaim_work_queue(mp);
 }
 
-void
+static void
 __xfs_inode_set_reclaim_tag(
         struct xfs_perag        *pag,
         struct xfs_inode        *ip)
@@ -319,7 +734,7 @@ __xfs_inode_clear_reclaim(
         }
 }
 
-void
+STATIC void
 __xfs_inode_clear_reclaim_tag(
         xfs_mount_t     *mp,
         xfs_perag_t     *pag,
@@ -542,7 +957,7 @@ out:
  * then a shut down during filesystem unmount reclaim walk leak all the
  * unreclaimed inodes.
  */
-int
+STATIC int
 xfs_reclaim_inodes_ag(
         struct xfs_mount        *mp,
         int                     flags,