[XFS] Make use of the init-once slab optimisation.

To avoid having to initialise some fields of the XFS inode on every
allocation, we can use the slab init-once feature to initialise them. All
we have to guarantee is that when we free the inode, all it's entries are
in the initial state. Add asserts where possible to ensure debug kernels
check this initial state before freeing and after allocation.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31925a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

1 files changed, 75 insertions, 36 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index dbd9cef852ec..b0c604e1bd47 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -788,6 +788,70 @@ xfs_dic2xflags(
 }
 
 /*
+ * Allocate and initialise an xfs_inode.
+ */
+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;
+
+        ASSERT(atomic_read(&ip->i_iocount) == 0);
+        ASSERT(atomic_read(&ip->i_pincount) == 0);
+        ASSERT(!spin_is_locked(&ip->i_flags_lock));
+        ASSERT(list_empty(&ip->i_reclaim));
+
+        ip->i_ino = ino;
+        ip->i_mount = mp;
+        ip->i_blkno = 0;
+        ip->i_len = 0;
+        ip->i_boffset =0;
+        ip->i_afp = NULL;
+        memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
+        ip->i_flags = 0;
+        ip->i_update_core = 0;
+        ip->i_update_size = 0;
+        ip->i_delayed_blks = 0;
+        memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
+        ip->i_size = 0;
+        ip->i_new_size = 0;
+
+        /*
+         * Initialize inode's trace buffers.
+         */
+#ifdef  XFS_INODE_TRACE
+        ip->i_trace = ktrace_alloc(INODE_TRACE_SIZE, KM_NOFS);
+#endif
+#ifdef XFS_BMAP_TRACE
+        ip->i_xtrace = ktrace_alloc(XFS_BMAP_KTRACE_SIZE, KM_NOFS);
+#endif
+#ifdef XFS_BMBT_TRACE
+        ip->i_btrace = ktrace_alloc(XFS_BMBT_KTRACE_SIZE, KM_NOFS);
+#endif
+#ifdef XFS_RW_TRACE
+        ip->i_rwtrace = ktrace_alloc(XFS_RW_KTRACE_SIZE, KM_NOFS);
+#endif
+#ifdef XFS_ILOCK_TRACE
+        ip->i_lock_trace = ktrace_alloc(XFS_ILOCK_KTRACE_SIZE, KM_NOFS);
+#endif
+#ifdef XFS_DIR2_TRACE
+        ip->i_dir_trace = ktrace_alloc(XFS_DIR2_KTRACE_SIZE, KM_NOFS);
+#endif
+
+        return ip;
+}
+
+/*
  * Given a mount structure and an inode number, return a pointer
  * to a newly allocated in-core inode corresponding to the given
  * inode number.
@@ -809,13 +873,9 @@ xfs_iread(
         xfs_inode_t     *ip;
         int             error;
 
-        ASSERT(xfs_inode_zone != NULL);
-
-        ip = kmem_zone_zalloc(xfs_inode_zone, KM_SLEEP);
-        ip->i_ino = ino;
-        ip->i_mount = mp;
-        atomic_set(&ip->i_iocount, 0);
-        spin_lock_init(&ip->i_flags_lock);
+        ip = xfs_inode_alloc(mp, ino);
+        if (!ip)
+                return ENOMEM;
 
         /*
          * Get pointer's to the on-disk inode and the buffer containing it.
@@ -831,34 +891,11 @@ xfs_iread(
         }
 
         /*
-         * Initialize inode's trace buffers.
-         * Do this before xfs_iformat in case it adds entries.
-         */
-#ifdef  XFS_INODE_TRACE
-        ip->i_trace = ktrace_alloc(INODE_TRACE_SIZE, KM_NOFS);
-#endif
-#ifdef XFS_BMAP_TRACE
-        ip->i_xtrace = ktrace_alloc(XFS_BMAP_KTRACE_SIZE, KM_NOFS);
-#endif
-#ifdef XFS_BMBT_TRACE
-        ip->i_btrace = ktrace_alloc(XFS_BMBT_KTRACE_SIZE, KM_NOFS);
-#endif
-#ifdef XFS_RW_TRACE
-        ip->i_rwtrace = ktrace_alloc(XFS_RW_KTRACE_SIZE, KM_NOFS);
-#endif
-#ifdef XFS_ILOCK_TRACE
-        ip->i_lock_trace = ktrace_alloc(XFS_ILOCK_KTRACE_SIZE, KM_NOFS);
-#endif
-#ifdef XFS_DIR2_TRACE
-        ip->i_dir_trace = ktrace_alloc(XFS_DIR2_KTRACE_SIZE, KM_NOFS);
-#endif
-
-        /*
          * If we got something that isn't an inode it means someone
          * (nfs or dmi) has a stale handle.
          */
         if (be16_to_cpu(dip->di_core.di_magic) != XFS_DINODE_MAGIC) {
-                kmem_zone_free(xfs_inode_zone, ip);
+                xfs_idestroy(ip);
                 xfs_trans_brelse(tp, bp);
 #ifdef DEBUG
                 xfs_fs_cmn_err(CE_ALERT, mp, "xfs_iread: "
@@ -881,7 +918,7 @@ xfs_iread(
                 xfs_dinode_from_disk(&ip->i_d, &dip->di_core);
                 error = xfs_iformat(ip, dip);
                 if (error)  {
-                        kmem_zone_free(xfs_inode_zone, ip);
+                        xfs_idestroy(ip);
                         xfs_trans_brelse(tp, bp);
 #ifdef DEBUG
                         xfs_fs_cmn_err(CE_ALERT, mp, "xfs_iread: "
@@ -911,8 +948,6 @@ xfs_iread(
                         XFS_IFORK_DSIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
         }
 
-        INIT_LIST_HEAD(&ip->i_reclaim);
-
         /*
          * The inode format changed when we moved the link count and
          * made it 32 bits long.  If this is an old format inode,
@@ -2631,8 +2666,6 @@ xfs_idestroy(
         }
         if (ip->i_afp)
                 xfs_idestroy_fork(ip, XFS_ATTR_FORK);
-        mrfree(&ip->i_lock);
-        mrfree(&ip->i_iolock);
 
 #ifdef XFS_INODE_TRACE
         ktrace_free(ip->i_trace);
@@ -2671,7 +2704,13 @@ xfs_idestroy(
                                 spin_unlock(&mp->m_ail_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(list_empty(&ip->i_reclaim));
         kmem_zone_free(xfs_inode_zone, ip);
 }