ocfs2: Make the ocfs2_caching_info structure self-contained.

We want to use the ocfs2_caching_info structure in places that are not
inodes.  To do that, it can no longer rely on referencing the inode
directly.

This patch moves the flags to ocfs2_caching_info->ci_flags, stores
pointers to the parent's locks on the ocfs2_caching_info, and renames
the constants and flags to reflect its independant state.

Signed-off-by: Joel Becker <joel.becker@oracle.com>

6 files changed, 80 insertions, 56 deletions

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 4dc8890ba316..8ec80445d18c 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1118,7 +1118,8 @@ void ocfs2_clear_inode(struct inode *inode)
                         "Clear inode of %llu, inode has %u cache items\n",
                         (unsigned long long)oi->ip_blkno, oi->ip_metadata_cache.ci_num_cached);
 
-        mlog_bug_on_msg(!(oi->ip_flags & OCFS2_INODE_CACHE_INLINE),
+        mlog_bug_on_msg(!(oi->ip_metadata_cache.ci_flags &
+                          OCFS2_CACHE_FL_INLINE),
                         "Clear inode of %llu, inode has a bad flag\n",
                         (unsigned long long)oi->ip_blkno);
 
@@ -1145,7 +1146,7 @@ void ocfs2_clear_inode(struct inode *inode)
                         (unsigned long long)oi->ip_blkno, oi->ip_open_count);
 
         /* Clear all other flags. */
-        oi->ip_flags = OCFS2_INODE_CACHE_INLINE;
+        oi->ip_flags = 0;
         oi->ip_created_trans = 0;
         oi->ip_last_trans = 0;
         oi->ip_dir_start_lookup = 0;
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index ea71525aad41..2f5e1aa0ccbf 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -106,8 +106,6 @@ struct ocfs2_inode_info
 #define OCFS2_INODE_MAYBE_ORPHANED      0x00000020
 /* Does someone have the file open O_DIRECT */
 #define OCFS2_INODE_OPEN_DIRECT         0x00000040
-/* Indicates that the metadata cache should be used as an array. */
-#define OCFS2_INODE_CACHE_INLINE        0x00000080
 
 static inline struct ocfs2_inode_info *OCFS2_I(struct inode *inode)
 {
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 39e1d5a39505..eef3bd077c10 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -51,17 +51,36 @@
 /* For struct ocfs2_blockcheck_stats */
 #include "blockcheck.h"
 
+
+/* Caching of metadata buffers */
+
 /* Most user visible OCFS2 inodes will have very few pieces of
  * metadata, but larger files (including bitmaps, etc) must be taken
  * into account when designing an access scheme. We allow a small
  * amount of inlined blocks to be stored on an array and grow the
  * structure into a rb tree when necessary. */
-#define OCFS2_INODE_MAX_CACHE_ARRAY 2
+#define OCFS2_CACHE_INFO_MAX_ARRAY 2
+
+/* Flags for ocfs2_caching_info */
+
+enum ocfs2_caching_info_flags {
+        /* Indicates that the metadata cache is using the inline array */
+        OCFS2_CACHE_FL_INLINE   = 1<<1,
+};
 
 struct ocfs2_caching_info {
+        /*
+         * The parent structure provides the locks, but because the
+         * parent structure can differ, struct ocfs2_caching_info needs
+         * its own pointers to them.
+         */
+        spinlock_t              *ci_lock;
+        struct mutex            *ci_io_mutex;
+
+        unsigned int            ci_flags;
         unsigned int            ci_num_cached;
         union {
-                sector_t        ci_array[OCFS2_INODE_MAX_CACHE_ARRAY];
+        sector_t        ci_array[OCFS2_CACHE_INFO_MAX_ARRAY];
                 struct rb_root  ci_tree;
         } ci_cache;
 };
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index a3f8871d21fd..8f217f6d1363 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1683,7 +1683,8 @@ static void ocfs2_inode_init_once(void *data)
         ocfs2_lock_res_init_once(&oi->ip_inode_lockres);
         ocfs2_lock_res_init_once(&oi->ip_open_lockres);
 
-        ocfs2_metadata_cache_init(&oi->vfs_inode);
+        ocfs2_metadata_cache_init(&oi->ip_metadata_cache, &oi->ip_lock,
+                                  &oi->ip_io_mutex);
 
         inode_init_once(&oi->vfs_inode);
 }
diff --git a/fs/ocfs2/uptodate.c b/fs/ocfs2/uptodate.c
index 187b99ff0368..8dbc457ba236 100644
--- a/fs/ocfs2/uptodate.c
+++ b/fs/ocfs2/uptodate.c
@@ -75,12 +75,13 @@ struct ocfs2_meta_cache_item {
 
 static struct kmem_cache *ocfs2_uptodate_cachep = NULL;
 
-void ocfs2_metadata_cache_init(struct inode *inode)
+void ocfs2_metadata_cache_init(struct ocfs2_caching_info *ci,
+                               spinlock_t *cache_lock,
+                               struct mutex *io_mutex)
 {
-        struct ocfs2_inode_info *oi = OCFS2_I(inode);
-        struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
-
-        oi->ip_flags |= OCFS2_INODE_CACHE_INLINE;
+        ci->ci_lock = cache_lock;
+        ci->ci_io_mutex = io_mutex;
+        ci->ci_flags |= OCFS2_CACHE_FL_INLINE;
         ci->ci_num_cached = 0;
 }
 
@@ -119,8 +120,8 @@ void ocfs2_metadata_cache_purge(struct inode *inode)
         struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
         struct rb_root root = RB_ROOT;
 
-        spin_lock(&oi->ip_lock);
-        tree = !(oi->ip_flags & OCFS2_INODE_CACHE_INLINE);
+        spin_lock(ci->ci_lock);
+        tree = !(ci->ci_flags & OCFS2_CACHE_FL_INLINE);
         to_purge = ci->ci_num_cached;
 
         mlog(0, "Purge %u %s items from Inode %llu\n", to_purge,
@@ -132,8 +133,8 @@ void ocfs2_metadata_cache_purge(struct inode *inode)
         if (tree)
                 root = ci->ci_cache.ci_tree;
 
-        ocfs2_metadata_cache_init(inode);
-        spin_unlock(&oi->ip_lock);
+        ocfs2_metadata_cache_init(ci, ci->ci_lock, ci->ci_io_mutex);
+        spin_unlock(ci->ci_lock);
 
         purged = ocfs2_purge_copied_metadata_tree(&root);
         /* If possible, track the number wiped so that we can more
@@ -187,22 +188,23 @@ static int ocfs2_buffer_cached(struct ocfs2_inode_info *oi,
 {
         int index = -1;
         struct ocfs2_meta_cache_item *item = NULL;
+        struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
 
-        spin_lock(&oi->ip_lock);
+        spin_lock(ci->ci_lock);
 
         mlog(0, "Inode %llu, query block %llu (inline = %u)\n",
              (unsigned long long)oi->ip_blkno,
              (unsigned long long) bh->b_blocknr,
-             !!(oi->ip_flags & OCFS2_INODE_CACHE_INLINE));
+             !!(ci->ci_flags & OCFS2_CACHE_FL_INLINE));
 
-        if (oi->ip_flags & OCFS2_INODE_CACHE_INLINE)
+        if (ci->ci_flags & OCFS2_CACHE_FL_INLINE)
                 index = ocfs2_search_cache_array(&oi->ip_metadata_cache,
                                                  bh->b_blocknr);
         else
                 item = ocfs2_search_cache_tree(&oi->ip_metadata_cache,
                                                bh->b_blocknr);
 
-        spin_unlock(&oi->ip_lock);
+        spin_unlock(ci->ci_lock);
 
         mlog(0, "index = %d, item = %p\n", index, item);
 
@@ -235,7 +237,7 @@ int ocfs2_buffer_uptodate(struct inode *inode,
 
 /* 
  * Determine whether a buffer is currently out on a read-ahead request.
- * ip_io_sem should be held to serialize submitters with the logic here.
+ * ci_io_sem should be held to serialize submitters with the logic here.
  */
 int ocfs2_buffer_read_ahead(struct inode *inode,
                             struct buffer_head *bh)
@@ -247,7 +249,7 @@ int ocfs2_buffer_read_ahead(struct inode *inode,
 static void ocfs2_append_cache_array(struct ocfs2_caching_info *ci,
                                      sector_t block)
 {
-        BUG_ON(ci->ci_num_cached >= OCFS2_INODE_MAX_CACHE_ARRAY);
+        BUG_ON(ci->ci_num_cached >= OCFS2_CACHE_INFO_MAX_ARRAY);
 
         mlog(0, "block %llu takes position %u\n", (unsigned long long) block,
              ci->ci_num_cached);
@@ -295,13 +297,13 @@ static void __ocfs2_insert_cache_tree(struct ocfs2_caching_info *ci,
 static inline int ocfs2_insert_can_use_array(struct ocfs2_inode_info *oi,
                                              struct ocfs2_caching_info *ci)
 {
-        assert_spin_locked(&oi->ip_lock);
+        assert_spin_locked(ci->ci_lock);
 
-        return (oi->ip_flags & OCFS2_INODE_CACHE_INLINE) &&
-                (ci->ci_num_cached < OCFS2_INODE_MAX_CACHE_ARRAY);
+        return (ci->ci_flags & OCFS2_CACHE_FL_INLINE) &&
+                (ci->ci_num_cached < OCFS2_CACHE_INFO_MAX_ARRAY);
 }
 
-/* tree should be exactly OCFS2_INODE_MAX_CACHE_ARRAY wide. NULL the
+/* tree should be exactly OCFS2_CACHE_INFO_MAX_ARRAY wide. NULL the
  * pointers in tree after we use them - this allows caller to detect
  * when to free in case of error. */
 static void ocfs2_expand_cache(struct ocfs2_inode_info *oi,
@@ -310,32 +312,32 @@ static void ocfs2_expand_cache(struct ocfs2_inode_info *oi,
         int i;
         struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
 
-        mlog_bug_on_msg(ci->ci_num_cached != OCFS2_INODE_MAX_CACHE_ARRAY,
+        mlog_bug_on_msg(ci->ci_num_cached != OCFS2_CACHE_INFO_MAX_ARRAY,
                         "Inode %llu, num cached = %u, should be %u\n",
                         (unsigned long long)oi->ip_blkno, ci->ci_num_cached,
-                        OCFS2_INODE_MAX_CACHE_ARRAY);
-        mlog_bug_on_msg(!(oi->ip_flags & OCFS2_INODE_CACHE_INLINE),
+                        OCFS2_CACHE_INFO_MAX_ARRAY);
+        mlog_bug_on_msg(!(ci->ci_flags & OCFS2_CACHE_FL_INLINE),
                         "Inode %llu not marked as inline anymore!\n",
                         (unsigned long long)oi->ip_blkno);
-        assert_spin_locked(&oi->ip_lock);
+        assert_spin_locked(ci->ci_lock);
 
         /* Be careful to initialize the tree members *first* because
          * once the ci_tree is used, the array is junk... */
-        for(i = 0; i < OCFS2_INODE_MAX_CACHE_ARRAY; i++)
+        for (i = 0; i < OCFS2_CACHE_INFO_MAX_ARRAY; i++)
                 tree[i]->c_block = ci->ci_cache.ci_array[i];
 
-        oi->ip_flags &= ~OCFS2_INODE_CACHE_INLINE;
+        ci->ci_flags &= ~OCFS2_CACHE_FL_INLINE;
         ci->ci_cache.ci_tree = RB_ROOT;
         /* this will be set again by __ocfs2_insert_cache_tree */
         ci->ci_num_cached = 0;
 
-        for(i = 0; i < OCFS2_INODE_MAX_CACHE_ARRAY; i++) {
+        for (i = 0; i < OCFS2_CACHE_INFO_MAX_ARRAY; i++) {
                 __ocfs2_insert_cache_tree(ci, tree[i]);
                 tree[i] = NULL;
         }
 
         mlog(0, "Expanded %llu to a tree cache: flags 0x%x, num = %u\n",
-             (unsigned long long)oi->ip_blkno, oi->ip_flags, ci->ci_num_cached);
+             (unsigned long long)oi->ip_blkno, ci->ci_flags, ci->ci_num_cached);
 }
 
 /* Slow path function - memory allocation is necessary. See the
@@ -347,7 +349,7 @@ static void __ocfs2_set_buffer_uptodate(struct ocfs2_inode_info *oi,
         int i;
         struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
         struct ocfs2_meta_cache_item *new = NULL;
-        struct ocfs2_meta_cache_item *tree[OCFS2_INODE_MAX_CACHE_ARRAY] =
+        struct ocfs2_meta_cache_item *tree[OCFS2_CACHE_INFO_MAX_ARRAY] =
                 { NULL, };
 
         mlog(0, "Inode %llu, block %llu, expand = %d\n",
@@ -364,7 +366,7 @@ static void __ocfs2_set_buffer_uptodate(struct ocfs2_inode_info *oi,
         if (expand_tree) {
                 /* Do *not* allocate an array here - the removal code
                  * has no way of tracking that. */
-                for(i = 0; i < OCFS2_INODE_MAX_CACHE_ARRAY; i++) {
+                for (i = 0; i < OCFS2_CACHE_INFO_MAX_ARRAY; i++) {
                         tree[i] = kmem_cache_alloc(ocfs2_uptodate_cachep,
                                                    GFP_NOFS);
                         if (!tree[i]) {
@@ -376,13 +378,13 @@ static void __ocfs2_set_buffer_uptodate(struct ocfs2_inode_info *oi,
                 }
         }
 
-        spin_lock(&oi->ip_lock);
+        spin_lock(ci->ci_lock);
         if (ocfs2_insert_can_use_array(oi, ci)) {
                 mlog(0, "Someone cleared the tree underneath us\n");
                 /* Ok, items were removed from the cache in between
                  * locks. Detect this and revert back to the fast path */
                 ocfs2_append_cache_array(ci, block);
-                spin_unlock(&oi->ip_lock);
+                spin_unlock(ci->ci_lock);
                 goto out_free;
         }
 
@@ -390,7 +392,7 @@ static void __ocfs2_set_buffer_uptodate(struct ocfs2_inode_info *oi,
                 ocfs2_expand_cache(oi, tree);
 
         __ocfs2_insert_cache_tree(ci, new);
-        spin_unlock(&oi->ip_lock);
+        spin_unlock(ci->ci_lock);
 
         new = NULL;
 out_free:
@@ -400,14 +402,14 @@ out_free:
         /* If these were used, then ocfs2_expand_cache re-set them to
          * NULL for us. */
         if (tree[0]) {
-                for(i = 0; i < OCFS2_INODE_MAX_CACHE_ARRAY; i++)
+                for (i = 0; i < OCFS2_CACHE_INFO_MAX_ARRAY; i++)
                         if (tree[i])
                                 kmem_cache_free(ocfs2_uptodate_cachep,
                                                 tree[i]);
         }
 }
 
-/* Item insertion is guarded by ip_io_mutex, so the insertion path takes
+/* Item insertion is guarded by ci_io_mutex, so the insertion path takes
  * advantage of this by not rechecking for a duplicate insert during
  * the slow case. Additionally, if the cache needs to be bumped up to
  * a tree, the code will not recheck after acquiring the lock --
@@ -442,42 +444,43 @@ void ocfs2_set_buffer_uptodate(struct inode *inode,
              (unsigned long long)bh->b_blocknr);
 
         /* No need to recheck under spinlock - insertion is guarded by
-         * ip_io_mutex */
-        spin_lock(&oi->ip_lock);
+         * ci_io_mutex */
+        spin_lock(ci->ci_lock);
         if (ocfs2_insert_can_use_array(oi, ci)) {
                 /* Fast case - it's an array and there's a free
                  * spot. */
                 ocfs2_append_cache_array(ci, bh->b_blocknr);
-                spin_unlock(&oi->ip_lock);
+                spin_unlock(ci->ci_lock);
                 return;
         }
 
         expand = 0;
-        if (oi->ip_flags & OCFS2_INODE_CACHE_INLINE) {
+        if (ci->ci_flags & OCFS2_CACHE_FL_INLINE) {
                 /* We need to bump things up to a tree. */
                 expand = 1;
         }
-        spin_unlock(&oi->ip_lock);
+        spin_unlock(ci->ci_lock);
 
         __ocfs2_set_buffer_uptodate(oi, bh->b_blocknr, expand);
 }
 
 /* Called against a newly allocated buffer. Most likely nobody should
  * be able to read this sort of metadata while it's still being
- * allocated, but this is careful to take ip_io_mutex anyway. */
+ * allocated, but this is careful to take ci_io_mutex anyway. */
 void ocfs2_set_new_buffer_uptodate(struct inode *inode,
                                    struct buffer_head *bh)
 {
         struct ocfs2_inode_info *oi = OCFS2_I(inode);
+        struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
 
         /* This should definitely *not* exist in our cache */
         BUG_ON(ocfs2_buffer_cached(oi, bh));
 
         set_buffer_uptodate(bh);
 
-        mutex_lock(&oi->ip_io_mutex);
+        mutex_lock(ci->ci_io_mutex);
         ocfs2_set_buffer_uptodate(inode, bh);
-        mutex_unlock(&oi->ip_io_mutex);
+        mutex_unlock(ci->ci_io_mutex);
 }
 
 /* Requires ip_lock. */
@@ -487,7 +490,7 @@ static void ocfs2_remove_metadata_array(struct ocfs2_caching_info *ci,
         sector_t *array = ci->ci_cache.ci_array;
         int bytes;
 
-        BUG_ON(index < 0 || index >= OCFS2_INODE_MAX_CACHE_ARRAY);
+        BUG_ON(index < 0 || index >= OCFS2_CACHE_INFO_MAX_ARRAY);
         BUG_ON(index >= ci->ci_num_cached);
         BUG_ON(!ci->ci_num_cached);
 
@@ -523,13 +526,13 @@ static void ocfs2_remove_block_from_cache(struct inode *inode,
         struct ocfs2_inode_info *oi = OCFS2_I(inode);
         struct ocfs2_caching_info *ci = &oi->ip_metadata_cache;
 
-        spin_lock(&oi->ip_lock);
+        spin_lock(ci->ci_lock);
         mlog(0, "Inode %llu, remove %llu, items = %u, array = %u\n",
              (unsigned long long)oi->ip_blkno,
              (unsigned long long) block, ci->ci_num_cached,
-             oi->ip_flags & OCFS2_INODE_CACHE_INLINE);
+             ci->ci_flags & OCFS2_CACHE_FL_INLINE);
 
-        if (oi->ip_flags & OCFS2_INODE_CACHE_INLINE) {
+        if (ci->ci_flags & OCFS2_CACHE_FL_INLINE) {
                 index = ocfs2_search_cache_array(ci, block);
                 if (index != -1)
                         ocfs2_remove_metadata_array(ci, index);
@@ -538,7 +541,7 @@ static void ocfs2_remove_block_from_cache(struct inode *inode,
                 if (item)
                         ocfs2_remove_metadata_tree(ci, item);
         }
-        spin_unlock(&oi->ip_lock);
+        spin_unlock(ci->ci_lock);
 
         if (item)
                 kmem_cache_free(ocfs2_uptodate_cachep, item);
@@ -577,7 +580,7 @@ int __init init_ocfs2_uptodate_cache(void)
                 return -ENOMEM;
 
         mlog(0, "%u inlined cache items per inode.\n",
-             OCFS2_INODE_MAX_CACHE_ARRAY);
+             OCFS2_CACHE_INFO_MAX_ARRAY);
 
         return 0;
 }
diff --git a/fs/ocfs2/uptodate.h b/fs/ocfs2/uptodate.h
index 531b4b3a0c47..bd749e1434f1 100644
--- a/fs/ocfs2/uptodate.h
+++ b/fs/ocfs2/uptodate.h
@@ -29,7 +29,9 @@
 int __init init_ocfs2_uptodate_cache(void);
 void exit_ocfs2_uptodate_cache(void);
 
-void ocfs2_metadata_cache_init(struct inode *inode);
+void ocfs2_metadata_cache_init(struct ocfs2_caching_info *ci,
+                               spinlock_t *cache_lock,
+                               struct mutex *io_mutex);
 void ocfs2_metadata_cache_purge(struct inode *inode);
 
 int ocfs2_buffer_uptodate(struct inode *inode,