UBIFS: add bulk-read facility

Some flash media are capable of reading sequentially at faster rates.
UBIFS bulk-read facility is designed to take advantage of that, by
reading in one go consecutive data nodes that are also located
consecutively in the same LEB.

Read speed on Arm platform with OneNAND goes from 17 MiB/s to
19 MiB/s.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>

1 files changed, 43 insertions, 2 deletions

diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index ce8654928aad..8513239ea8a0 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -142,6 +142,9 @@
 /* Maximum expected tree height for use by bottom_up_buf */
 #define BOTTOM_UP_HEIGHT 64
 
+/* Maximum number of data nodes to bulk-read */
+#define UBIFS_MAX_BULK_READ 32
+
 /*
  * Lockdep classes for UBIFS inode @ui_mutex.
  */
@@ -329,8 +332,8 @@ struct ubifs_gced_idx_leb {
  * @dirty: non-zero if the inode is dirty
  * @xattr: non-zero if this is an extended attribute inode
  * @ui_mutex: serializes inode write-back with the rest of VFS operations,
- *            serializes "clean <-> dirty" state changes, protects @dirty,
- *            @ui_size, and @xattr_size
+ *            serializes "clean <-> dirty" state changes, serializes bulk-read,
+ *            protects @dirty, @ui_size, and @xattr_size
  * @ui_lock: protects @synced_i_size
  * @synced_i_size: synchronized size of inode, i.e. the value of inode size
  *                 currently stored on the flash; used only for regular file
@@ -338,6 +341,9 @@ struct ubifs_gced_idx_leb {
  * @ui_size: inode size used by UBIFS when writing to flash
  * @flags: inode flags (@UBIFS_COMPR_FL, etc)
  * @compr_type: default compression type used for this inode
+ * @last_page_read: page number of last page read (for bulk read)
+ * @read_in_a_row: number of consecutive pages read in a row (for bulk read)
+ * @bulk_read: indicates whether bulk-read should be used
  * @data_len: length of the data attached to the inode
  * @data: inode's data
  *
@@ -385,6 +391,9 @@ struct ubifs_inode {
         loff_t ui_size;
         int flags;
         int compr_type;
+        pgoff_t last_page_read;
+        pgoff_t read_in_a_row;
+        int bulk_read;
         int data_len;
         void *data;
 };
@@ -744,6 +753,28 @@ struct ubifs_znode {
 };
 
 /**
+ * struct bu_info - bulk-read information
+ * @key: first data node key
+ * @zbranch: zbranches of data nodes to bulk read
+ * @buf: buffer to read into
+ * @buf_len: buffer length
+ * @gc_seq: GC sequence number to detect races with GC
+ * @cnt: number of data nodes for bulk read
+ * @blk_cnt: number of data blocks including holes
+ * @oef: end of file reached
+ */
+struct bu_info {
+        union ubifs_key key;
+        struct ubifs_zbranch zbranch[UBIFS_MAX_BULK_READ];
+        void *buf;
+        int buf_len;
+        int gc_seq;
+        int cnt;
+        int blk_cnt;
+        int eof;
+};
+
+/**
  * struct ubifs_node_range - node length range description data structure.
  * @len: fixed node length
  * @min_len: minimum possible node length
@@ -862,9 +893,11 @@ struct ubifs_orphan {
 /**
  * struct ubifs_mount_opts - UBIFS-specific mount options information.
  * @unmount_mode: selected unmount mode (%0 default, %1 normal, %2 fast)
+ * @bulk_read: enable bulk-reads
  */
 struct ubifs_mount_opts {
         unsigned int unmount_mode:2;
+        unsigned int bulk_read:2;
 };
 
 /**
@@ -965,6 +998,9 @@ struct ubifs_mount_opts {
  * @old_leb_cnt: count of logical eraseblocks before re-size
  * @ro_media: the underlying UBI volume is read-only
  *
+ * @bulk_read: enable bulk-reads
+ * @bulk_read_buf_size: buffer size for bulk-reads
+ *
  * @dirty_pg_cnt: number of dirty pages (not used)
  * @dirty_zn_cnt: number of dirty znodes
  * @clean_zn_cnt: number of clean znodes
@@ -1205,6 +1241,9 @@ struct ubifs_info {
         int old_leb_cnt;
         int ro_media;
 
+        int bulk_read;
+        int bulk_read_buf_size;
+
         atomic_long_t dirty_pg_cnt;
         atomic_long_t dirty_zn_cnt;
         atomic_long_t clean_zn_cnt;
@@ -1490,6 +1529,8 @@ void destroy_old_idx(struct ubifs_info *c);
 int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
                        int lnum, int offs);
 int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode);
+int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu);
+int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu);
 
 /* tnc_misc.c */
 struct ubifs_znode *ubifs_tnc_levelorder_next(struct ubifs_znode *zr,