ath5k: fix NULL pointer in antenna configuration
[safe/jmp/linux-2.6] / fs / xfs / xfs_iget.c
index a1f209b..6845db9 100644 (file)
@@ -18,6 +18,7 @@
 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_types.h"
+#include "xfs_acl.h"
 #include "xfs_bit.h"
 #include "xfs_log.h"
 #include "xfs_inum.h"
 #include "xfs_utils.h"
 #include "xfs_trans_priv.h"
 #include "xfs_inode_item.h"
+#include "xfs_bmap.h"
+#include "xfs_btree_trace.h"
+#include "xfs_trace.h"
+
+
+/*
+ * 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_iocount) == 0);
+       ASSERT(atomic_read(&ip->i_pincount) == 0);
+       ASSERT(!spin_is_locked(&ip->i_flags_lock));
+       ASSERT(completion_done(&ip->i_flush));
+
+       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_update_core = 0;
+       ip->i_delayed_blks = 0;
+       memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
+       ip->i_size = 0;
+       ip->i_new_size = 0;
+
+       /* prevent anyone from using this yet */
+       VFS_I(ip)->i_state = I_NEW;
+
+       return 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) {
+               /*
+                * Only if we are shutting down the fs will we see an
+                * inode still in the AIL. If it is there, we should remove
+                * it to prevent a use-after-free from occurring.
+                */
+               xfs_log_item_t  *lip = &ip->i_itemp->ili_item;
+               struct xfs_ail  *ailp = lip->li_ailp;
+
+               ASSERT(((lip->li_flags & XFS_LI_IN_AIL) == 0) ||
+                                      XFS_FORCED_SHUTDOWN(ip->i_mount));
+               if (lip->li_flags & XFS_LI_IN_AIL) {
+                       spin_lock(&ailp->xa_lock);
+                       if (lip->li_flags & XFS_LI_IN_AIL)
+                               xfs_trans_ail_delete(ailp, lip);
+                       else
+                               spin_unlock(&ailp->xa_lock);
+               }
+               xfs_inode_item_destroy(ip);
+               ip->i_itemp = NULL;
+       }
+
+       /* asserts to verify all state is correct here */
+       ASSERT(atomic_read(&ip->i_iocount) == 0);
+       ASSERT(atomic_read(&ip->i_pincount) == 0);
+       ASSERT(!spin_is_locked(&ip->i_flags_lock));
+       ASSERT(completion_done(&ip->i_flush));
+
+       kmem_zone_free(xfs_inode_zone, ip);
+}
 
 /*
  * Check the validity of the inode we just found it the cache
@@ -51,78 +151,103 @@ xfs_iget_cache_hit(
        int                     flags,
        int                     lock_flags) __releases(pag->pag_ici_lock)
 {
+       struct inode            *inode = VFS_I(ip);
        struct xfs_mount        *mp = ip->i_mount;
-       int                     error = 0;
+       int                     error;
+
+       spin_lock(&ip->i_flags_lock);
 
        /*
-        * 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 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 (xfs_iflags_test(ip, (XFS_INEW|XFS_IRECLAIM))) {
-               error = EAGAIN;
+       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 IRECLAIMABLE is set, we've torn down the vfs inode part */
-       if (xfs_iflags_test(ip, XFS_IRECLAIMABLE)) {
+       /*
+        * 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);
 
                /*
-                * 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.
+                * 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;
 
-               if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
-                       error = ENOENT;
-                       goto out_error;
-               }
-
-               xfs_itrace_exit_tag(ip, "xfs_iget.alloc");
+               spin_unlock(&ip->i_flags_lock);
+               read_unlock(&pag->pag_ici_lock);
 
-               /*
-                * 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.
-                */
-               if (!inode_init_always(mp->m_super, VFS_I(ip))) {
-                       error = ENOMEM;
+               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.
+                        */
+                       read_lock(&pag->pag_ici_lock);
+                       spin_lock(&ip->i_flags_lock);
+
+                       ip->i_flags &= ~XFS_INEW;
+                       ip->i_flags |= XFS_IRECLAIMABLE;
+                       __xfs_inode_set_reclaim_tag(pag, ip);
+                       trace_xfs_iget_reclaim(ip);
                        goto out_error;
                }
-               xfs_iflags_set(ip, XFS_INEW);
-               xfs_iflags_clear(ip, XFS_IRECLAIMABLE);
 
-               /* clear the radix tree reclaim flag as well. */
+               write_lock(&pag->pag_ici_lock);
+               spin_lock(&ip->i_flags_lock);
+               ip->i_flags &= ~(XFS_IRECLAIMABLE | XFS_IRECLAIM);
+               ip->i_flags |= XFS_INEW;
                __xfs_inode_clear_reclaim_tag(mp, pag, ip);
-               read_unlock(&pag->pag_ici_lock);
-       } else if (!igrab(VFS_I(ip))) {
-               /* If the VFS inode is being torn down, pause and try again. */
-               error = EAGAIN;
-               XFS_STATS_INC(xs_ig_frecycle);
-               goto out_error;
+               inode->i_state = I_NEW;
+               spin_unlock(&ip->i_flags_lock);
+               write_unlock(&pag->pag_ici_lock);
        } else {
-               /* we've got a live one */
-               read_unlock(&pag->pag_ici_lock);
-       }
+               /* If the VFS inode is being torn down, pause and try again. */
+               if (!igrab(inode)) {
+                       error = EAGAIN;
+                       goto out_error;
+               }
 
-       if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
-               error = ENOENT;
-               goto out;
+               /* We've got a live one. */
+               spin_unlock(&ip->i_flags_lock);
+               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);
+
+       trace_xfs_iget_found(ip);
        return 0;
 
 out_error:
+       spin_unlock(&ip->i_flags_lock);
        read_unlock(&pag->pag_ici_lock);
-out:
        return error;
 }
 
@@ -136,23 +261,22 @@ xfs_iget_cache_miss(
        struct xfs_inode        **ipp,
        xfs_daddr_t             bno,
        int                     flags,
-       int                     lock_flags) __releases(pag->pag_ici_lock)
+       int                     lock_flags)
 {
        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
-        * a new vnode for it. This should also initialize i_ino and i_mount.
-        */
-       error = xfs_iread(mp, tp, ino, &ip, bno,
-                         (flags & XFS_IGET_BULKSTAT) ? XFS_IMAP_BULKSTAT : 0);
+       ip = xfs_inode_alloc(mp, ino);
+       if (!ip)
+               return ENOMEM;
+
+       error = xfs_iread(mp, tp, ip, bno, flags);
        if (error)
-               return error;
+               goto out_destroy;
 
-       xfs_itrace_exit_tag(ip, "xfs_iget.alloc");
+       xfs_itrace_entry(ip);
 
        if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
                error = ENOENT;
@@ -161,15 +285,22 @@ xfs_iget_cache_miss(
 
        /*
         * 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)) {
                error = EAGAIN;
                goto out_destroy;
        }
 
-       if (lock_flags)
-               xfs_ilock(ip, lock_flags);
+       /*
+        * 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();
+       }
 
        mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
        first_index = agino & mask;
@@ -181,7 +312,7 @@ xfs_iget_cache_miss(
                WARN_ON(error != -EEXIST);
                XFS_STATS_INC(xs_ig_dup);
                error = EAGAIN;
-               goto out_unlock;
+               goto out_preload_end;
        }
 
        /* These values _must_ be set before releasing the radix tree lock! */
@@ -190,14 +321,19 @@ xfs_iget_cache_miss(
 
        write_unlock(&pag->pag_ici_lock);
        radix_tree_preload_end();
+
+       trace_xfs_iget_alloc(ip);
        *ipp = ip;
        return 0;
 
-out_unlock:
+out_preload_end:
        write_unlock(&pag->pag_ici_lock);
        radix_tree_preload_end();
+       if (lock_flags)
+               xfs_iunlock(ip, lock_flags);
 out_destroy:
-       xfs_idestroy(ip);
+       __destroy_inode(VFS_I(ip));
+       xfs_inode_free(ip);
        return error;
 }
 
@@ -245,7 +381,7 @@ xfs_iget(
                return EINVAL;
 
        /* get the perag structure and ensure that it's inode capable */
-       pag = xfs_get_perag(mp, ino);
+       pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
        if (!pag->pagi_inodeok)
                return EINVAL;
        ASSERT(pag->pag_ici_init);
@@ -269,9 +405,8 @@ again:
                if (error)
                        goto out_error_or_again;
        }
-       xfs_put_perag(mp, pag);
+       xfs_perag_put(pag);
 
-       xfs_iflags_set(ip, XFS_IMODIFIED);
        *ipp = ip;
 
        ASSERT(ip->i_df.if_ext_max ==
@@ -289,36 +424,10 @@ out_error_or_again:
                delay(1);
                goto again;
        }
-       xfs_put_perag(mp, pag);
+       xfs_perag_put(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.
- * Otherwise, return NULL.
- */
-xfs_inode_t *
-xfs_inode_incore(xfs_mount_t   *mp,
-                xfs_ino_t      ino,
-                xfs_trans_t    *tp)
-{
-       xfs_inode_t     *ip;
-       xfs_perag_t     *pag;
-
-       pag = xfs_get_perag(mp, ino);
-       read_lock(&pag->pag_ici_lock);
-       ip = radix_tree_lookup(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ino));
-       read_unlock(&pag->pag_ici_lock);
-       xfs_put_perag(mp, pag);
-
-       /* the returned inode must match the transaction */
-       if (ip && (ip->i_transp != tp))
-               return NULL;
-       return ip;
-}
-
 /*
  * Decrement reference count of an inode structure and unlock it.
  *
@@ -359,65 +468,55 @@ xfs_iput_new(
        IRELE(ip);
 }
 
-
 /*
- * This routine embodies the part of the reclaim code that pulls
- * the inode from the inode hash table and the mount structure's
- * inode list.
- * This should only be called from xfs_reclaim().
+ * This is called free all the memory associated with an inode.
+ * It must free the inode itself and any buffers allocated for
+ * if_extents/if_data and if_broot.  It must also free the lock
+ * associated with the inode.
+ *
+ * Note: because we don't initialise everything on reallocation out
+ * of the zone, we must ensure we nullify everything correctly before
+ * freeing the structure.
  */
 void
-xfs_ireclaim(xfs_inode_t *ip)
+xfs_ireclaim(
+       struct xfs_inode        *ip)
 {
-       /*
-        * Remove from old hash list and mount list.
-        */
-       XFS_STATS_INC(xs_ig_reclaims);
-
-       xfs_iextract(ip);
+       struct xfs_mount        *mp = ip->i_mount;
+       struct xfs_perag        *pag;
+       xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
 
-       /*
-        * 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);
+       XFS_STATS_INC(xs_ig_reclaims);
 
        /*
-        * Release dquots (and their references) if any. An inode may escape
-        * xfs_inactive and get here via vn_alloc->vn_reclaim path.
+        * Remove the inode from the per-AG radix tree.
+        *
+        * Because radix_tree_delete won't complain even if the item was never
+        * added to the tree assert that it's been there before to catch
+        * problems with the inode life time early on.
         */
-       XFS_QM_DQDETACH(ip->i_mount, ip);
+       pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+       write_lock(&pag->pag_ici_lock);
+       if (!radix_tree_delete(&pag->pag_ici_root, agino))
+               ASSERT(0);
+       write_unlock(&pag->pag_ici_lock);
+       xfs_perag_put(pag);
 
        /*
-        * Free all memory associated with the inode.
+        * Here we do an (almost) 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);
+       xfs_qm_dqdetach(ip);
        xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
-       xfs_idestroy(ip);
-}
-
-/*
- * This routine removes an about-to-be-destroyed inode from
- * all of the lists in which it is located with the exception
- * of the behavior chain.
- */
-void
-xfs_iextract(
-       xfs_inode_t     *ip)
-{
-       xfs_mount_t     *mp = ip->i_mount;
-       xfs_perag_t     *pag = xfs_get_perag(mp, ip->i_ino);
 
-       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);
-
-       mp->m_ireclaims++;
+       xfs_inode_free(ip);
 }
 
 /*
@@ -514,7 +613,7 @@ xfs_ilock(
        else if (lock_flags & XFS_ILOCK_SHARED)
                mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
 
-       xfs_ilock_trace(ip, 1, lock_flags, (inst_t *)__return_address);
+       trace_xfs_ilock(ip, lock_flags, _RET_IP_);
 }
 
 /*
@@ -559,7 +658,7 @@ xfs_ilock_nowait(
                if (!mrtryaccess(&ip->i_lock))
                        goto out_undo_iolock;
        }
-       xfs_ilock_trace(ip, 2, lock_flags, (inst_t *)__return_address);
+       trace_xfs_ilock_nowait(ip, lock_flags, _RET_IP_);
        return 1;
 
  out_undo_iolock:
@@ -621,7 +720,7 @@ xfs_iunlock(
                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);
+       trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
 }
 
 /*
@@ -640,6 +739,8 @@ xfs_ilock_demote(
                mrdemote(&ip->i_lock);
        if (lock_flags & XFS_IOLOCK_EXCL)
                mrdemote(&ip->i_iolock);
+
+       trace_xfs_ilock_demote(ip, lock_flags, _RET_IP_);
 }
 
 #ifdef DEBUG
@@ -670,4 +771,3 @@ xfs_isilocked(
        return 1;
 }
 #endif
-