f2fs: reduce competition among node page writes

We do not need to block on ->node_write among different node page writers e.g.
fsync/flush, unless we have a node page writer from write_checkpoint.
So it's better use rw_semaphore instead of mutex type for ->node_write to
promote performance.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

4 files changed, 7 insertions, 7 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index cea20b810f44..6aeed5bada52 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -762,10 +762,10 @@ retry_flush_dents:
          * until finishing nat/sit flush.
          */
 retry_flush_nodes:
-        mutex_lock(&sbi->node_write);
+        down_write(&sbi->node_write);
 
         if (get_pages(sbi, F2FS_DIRTY_NODES)) {
-                mutex_unlock(&sbi->node_write);
+                up_write(&sbi->node_write);
                 sync_node_pages(sbi, 0, &wbc);
                 goto retry_flush_nodes;
         }
@@ -774,7 +774,7 @@ retry_flush_nodes:
 
 static void unblock_operations(struct f2fs_sb_info *sbi)
 {
-        mutex_unlock(&sbi->node_write);
+        up_write(&sbi->node_write);
         f2fs_unlock_all(sbi);
 }
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 80c78695546d..99425675c2f8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -452,7 +452,7 @@ struct f2fs_sb_info {
         struct inode *meta_inode;               /* cache meta blocks */
         struct mutex cp_mutex;                  /* checkpoint procedure lock */
         struct rw_semaphore cp_rwsem;           /* blocking FS operations */
-        struct mutex node_write;                /* locking node writes */
+        struct rw_semaphore node_write;         /* locking node writes */
         struct mutex writepages;                /* mutex for writepages() */
         bool por_doing;                         /* recovery is doing or not */
         wait_queue_head_t cp_wait;
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index a90f51d32482..7b5b5def65fe 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1231,12 +1231,12 @@ static int f2fs_write_node_page(struct page *page,
         if (wbc->for_reclaim)
                 goto redirty_out;
 
-        mutex_lock(&sbi->node_write);
+        down_read(&sbi->node_write);
         set_page_writeback(page);
         write_node_page(sbi, page, &fio, nid, ni.blk_addr, &new_addr);
         set_node_addr(sbi, &ni, new_addr, is_fsync_dnode(page));
         dec_page_count(sbi, F2FS_DIRTY_NODES);
-        mutex_unlock(&sbi->node_write);
+        up_read(&sbi->node_write);
         unlock_page(page);
         return 0;
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index f253e222dcea..657582fc7601 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -953,7 +953,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
         mutex_init(&sbi->gc_mutex);
         mutex_init(&sbi->writepages);
         mutex_init(&sbi->cp_mutex);
-        mutex_init(&sbi->node_write);
+        init_rwsem(&sbi->node_write);
         sbi->por_doing = false;
         spin_lock_init(&sbi->stat_lock);