btrfs: turn the backref sharedness check cache into a context object

Right now we are using a struct btrfs_backref_shared_cache to pass state
across multiple btrfs_is_data_extent_shared() calls. The structure's name
closely follows its current purpose, which is to cache previous checks
for the sharedness of metadata extents. However we will start using the
structure for more things other than caching sharedness checks, so rename
it to struct btrfs_backref_share_check_ctx.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 16 insertions, 16 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index efdeb69e8ed6..693c99ad4afb 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1542,13 +1542,13 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
  * fs_info->commit_root_sem semaphore, so no need to worry about the root's last
  * snapshot field changing while updating or checking the cache.
  */
-static bool lookup_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
+static bool lookup_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx,
 					struct btrfs_root *root,
 					u64 bytenr, int level, bool *is_shared)
 {
 	struct btrfs_backref_shared_cache_entry *entry;
 
-	if (!cache->use_cache)
+	if (!ctx->use_path_cache)
 		return false;
 
 	if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL))
@@ -1562,7 +1562,7 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_shared_cache *cache
 	 */
 	ASSERT(level >= 0);
 
-	entry = &cache->entries[level];
+	entry = &ctx->path_cache_entries[level];
 
 	/* Unused cache entry or being used for some other extent buffer. */
 	if (entry->bytenr != bytenr)
@@ -1595,8 +1595,8 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_shared_cache *cache
 	 */
 	if (*is_shared) {
 		for (int i = 0; i < level; i++) {
-			cache->entries[i].is_shared = true;
-			cache->entries[i].gen = entry->gen;
+			ctx->path_cache_entries[i].is_shared = true;
+			ctx->path_cache_entries[i].gen = entry->gen;
 		}
 	}
 
@@ -1608,14 +1608,14 @@ static bool lookup_backref_shared_cache(struct btrfs_backref_shared_cache *cache
  * fs_info->commit_root_sem semaphore, so no need to worry about the root's last
  * snapshot field changing while updating or checking the cache.
  */
-static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
+static void store_backref_shared_cache(struct btrfs_backref_share_check_ctx *ctx,
 				       struct btrfs_root *root,
 				       u64 bytenr, int level, bool is_shared)
 {
 	struct btrfs_backref_shared_cache_entry *entry;
 	u64 gen;
 
-	if (!cache->use_cache)
+	if (!ctx->use_path_cache)
 		return;
 
 	if (WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL))
@@ -1634,7 +1634,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
 	else
 		gen = btrfs_root_last_snapshot(&root->root_item);
 
-	entry = &cache->entries[level];
+	entry = &ctx->path_cache_entries[level];
 	entry->bytenr = bytenr;
 	entry->is_shared = is_shared;
 	entry->gen = gen;
@@ -1648,7 +1648,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
 	 */
 	if (is_shared) {
 		for (int i = 0; i < level; i++) {
-			entry = &cache->entries[i];
+			entry = &ctx->path_cache_entries[i];
 			entry->is_shared = is_shared;
 			entry->gen = gen;
 		}
@@ -1664,7 +1664,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
  *               not known.
  * @roots:       List of roots this extent is shared among.
  * @tmp:         Temporary list used for iteration.
- * @cache:       A backref lookup result cache.
+ * @ctx:         A backref sharedness check context.
  *
  * btrfs_is_data_extent_shared uses the backref walking code but will short
  * circuit as soon as it finds a root or inode that doesn't match the
@@ -1680,7 +1680,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
 int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 				u64 extent_gen,
 				struct ulist *roots, struct ulist *tmp,
-				struct btrfs_backref_shared_cache *cache)
+				struct btrfs_backref_share_check_ctx *ctx)
 {
 	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -1715,7 +1715,7 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 	/* -1 means we are in the bytenr of the data extent. */
 	level = -1;
 	ULIST_ITER_INIT(&uiter);
-	cache->use_cache = true;
+	ctx->use_path_cache = true;
 	while (1) {
 		bool is_shared;
 		bool cached;
@@ -1726,7 +1726,7 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 			/* this is the only condition under which we return 1 */
 			ret = 1;
 			if (level >= 0)
-				store_backref_shared_cache(cache, root, bytenr,
+				store_backref_shared_cache(ctx, root, bytenr,
 							   level, true);
 			break;
 		}
@@ -1761,17 +1761,17 @@ int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 		 * (which implies multiple paths).
 		 */
 		if (level == -1 && tmp->nnodes > 1)
-			cache->use_cache = false;
+			ctx->use_path_cache = false;
 
 		if (level >= 0)
-			store_backref_shared_cache(cache, root, bytenr,
+			store_backref_shared_cache(ctx, root, bytenr,
 						   level, false);
 		node = ulist_next(tmp, &uiter);
 		if (!node)
 			break;
 		bytenr = node->val;
 		level++;
-		cached = lookup_backref_shared_cache(cache, root, bytenr, level,
+		cached = lookup_backref_shared_cache(ctx, root, bytenr, level,
 						     &is_shared);
 		if (cached) {
 			ret = (is_shared ? 1 : 0);