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Diffstat (limited to 'fs/ext4/extents_status.h')
-rw-r--r--fs/ext4/extents_status.h80
1 files changed, 77 insertions, 3 deletions
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 8efdeb903d6b..131a8b7df265 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -78,6 +78,51 @@ struct ext4_es_stats {
struct percpu_counter es_stats_shk_cnt;
};
+/*
+ * Pending cluster reservations for bigalloc file systems
+ *
+ * A cluster with a pending reservation is a logical cluster shared by at
+ * least one extent in the extents status tree with delayed and unwritten
+ * status and at least one other written or unwritten extent. The
+ * reservation is said to be pending because a cluster reservation would
+ * have to be taken in the event all blocks in the cluster shared with
+ * written or unwritten extents were deleted while the delayed and
+ * unwritten blocks remained.
+ *
+ * The set of pending cluster reservations is an auxiliary data structure
+ * used with the extents status tree to implement reserved cluster/block
+ * accounting for bigalloc file systems. The set is kept in memory and
+ * records all pending cluster reservations.
+ *
+ * Its primary function is to avoid the need to read extents from the
+ * disk when invalidating pages as a result of a truncate, punch hole, or
+ * collapse range operation. Page invalidation requires a decrease in the
+ * reserved cluster count if it results in the removal of all delayed
+ * and unwritten extents (blocks) from a cluster that is not shared with a
+ * written or unwritten extent, and no decrease otherwise. Determining
+ * whether the cluster is shared can be done by searching for a pending
+ * reservation on it.
+ *
+ * Secondarily, it provides a potentially faster method for determining
+ * whether the reserved cluster count should be increased when a physical
+ * cluster is deallocated as a result of a truncate, punch hole, or
+ * collapse range operation. The necessary information is also present
+ * in the extents status tree, but might be more rapidly accessed in
+ * the pending reservation set in many cases due to smaller size.
+ *
+ * The pending cluster reservation set is implemented as a red-black tree
+ * with the goal of minimizing per page search time overhead.
+ */
+
+struct pending_reservation {
+ struct rb_node rb_node;
+ ext4_lblk_t lclu;
+};
+
+struct ext4_pending_tree {
+ struct rb_root root;
+};
+
extern int __init ext4_init_es(void);
extern void ext4_exit_es(void);
extern void ext4_es_init_tree(struct ext4_es_tree *tree);
@@ -90,11 +135,18 @@ extern void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
unsigned int status);
extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len);
-extern void ext4_es_find_delayed_extent_range(struct inode *inode,
- ext4_lblk_t lblk, ext4_lblk_t end,
- struct extent_status *es);
+extern void ext4_es_find_extent_range(struct inode *inode,
+ int (*match_fn)(struct extent_status *es),
+ ext4_lblk_t lblk, ext4_lblk_t end,
+ struct extent_status *es);
extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
struct extent_status *es);
+extern bool ext4_es_scan_range(struct inode *inode,
+ int (*matching_fn)(struct extent_status *es),
+ ext4_lblk_t lblk, ext4_lblk_t end);
+extern bool ext4_es_scan_clu(struct inode *inode,
+ int (*matching_fn)(struct extent_status *es),
+ ext4_lblk_t lblk);
static inline unsigned int ext4_es_status(struct extent_status *es)
{
@@ -126,6 +178,16 @@ static inline int ext4_es_is_hole(struct extent_status *es)
return (ext4_es_type(es) & EXTENT_STATUS_HOLE) != 0;
}
+static inline int ext4_es_is_mapped(struct extent_status *es)
+{
+ return (ext4_es_is_written(es) || ext4_es_is_unwritten(es));
+}
+
+static inline int ext4_es_is_delonly(struct extent_status *es)
+{
+ return (ext4_es_is_delayed(es) && !ext4_es_is_unwritten(es));
+}
+
static inline void ext4_es_set_referenced(struct extent_status *es)
{
es->es_pblk |= ((ext4_fsblk_t)EXTENT_STATUS_REFERENCED) << ES_SHIFT;
@@ -175,4 +237,16 @@ extern void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi);
extern int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v);
+extern int __init ext4_init_pending(void);
+extern void ext4_exit_pending(void);
+extern void ext4_init_pending_tree(struct ext4_pending_tree *tree);
+extern void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk);
+extern bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk);
+extern int ext4_es_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk,
+ bool allocated);
+extern unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len);
+extern void ext4_es_remove_blks(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len);
+
#endif /* _EXT4_EXTENTS_STATUS_H */