f2fs: rename dio_rwsem to i_gc_rwsem

RW semphore dio_rwsem in struct f2fs_inode_info is introduced to avoid
race between dio and data gc, but now, it is more wildly used to avoid
foreground operation vs data gc. So rename it to i_gc_rwsem to improve
its readability.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index ac8720f..72287fa 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2401,17 +2401,17 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	if (rw == WRITE && whint_mode == WHINT_MODE_OFF)
 		iocb->ki_hint = WRITE_LIFE_NOT_SET;
 
-	if (!down_read_trylock(&F2FS_I(inode)->dio_rwsem[rw])) {
+	if (!down_read_trylock(&F2FS_I(inode)->i_gc_rwsem[rw])) {
 		if (iocb->ki_flags & IOCB_NOWAIT) {
 			iocb->ki_hint = hint;
 			err = -EAGAIN;
 			goto out;
 		}
-		down_read(&F2FS_I(inode)->dio_rwsem[rw]);
+		down_read(&F2FS_I(inode)->i_gc_rwsem[rw]);
 	}
 
 	err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
-	up_read(&F2FS_I(inode)->dio_rwsem[rw]);
+	up_read(&F2FS_I(inode)->i_gc_rwsem[rw]);
 
 	if (rw == WRITE) {
 		if (whint_mode == WHINT_MODE_OFF)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c2d1208..7d19fd0 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -653,7 +653,9 @@ struct f2fs_inode_info {
 	struct task_struct *inmem_task;	/* store inmemory task */
 	struct mutex inmem_lock;	/* lock for inmemory pages */
 	struct extent_tree *extent_tree;	/* cached extent_tree entry */
-	struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */
+
+	/* avoid racing between foreground op and gc */
+	struct rw_semaphore i_gc_rwsem[2];
 	struct rw_semaphore i_mmap_sem;
 	struct rw_semaphore i_xattr_sem; /* avoid racing between reading and changing EAs */
 
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1066872..8af352c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1187,7 +1187,7 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
 	pg_end = (offset + len) >> PAGE_SHIFT;
 
 	/* avoid gc operation during block exchange */
-	down_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 
 	down_write(&F2FS_I(inode)->i_mmap_sem);
 	/* write out all dirty pages from offset */
@@ -1213,7 +1213,7 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
 		f2fs_i_size_write(inode, new_size);
 out_unlock:
 	up_write(&F2FS_I(inode)->i_mmap_sem);
-	up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	return ret;
 }
 
@@ -1389,7 +1389,7 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 	f2fs_balance_fs(sbi, true);
 
 	/* avoid gc operation during block exchange */
-	down_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 
 	down_write(&F2FS_I(inode)->i_mmap_sem);
 	ret = truncate_blocks(inode, i_size_read(inode), true);
@@ -1430,7 +1430,7 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 		f2fs_i_size_write(inode, new_size);
 out:
 	up_write(&F2FS_I(inode)->i_mmap_sem);
-	up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	return ret;
 }
 
@@ -1677,7 +1677,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
 
 	inode_lock(inode);
 
-	down_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 
 	if (f2fs_is_atomic_file(inode))
 		goto out;
@@ -1704,7 +1704,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
 	stat_inc_atomic_write(inode);
 	stat_update_max_atomic_write(inode);
 out:
-	up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	inode_unlock(inode);
 	mnt_drop_write_file(filp);
 	return ret;
@@ -1724,7 +1724,7 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
 
 	inode_lock(inode);
 
-	down_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 
 	if (f2fs_is_volatile_file(inode)) {
 		ret = -EINVAL;
@@ -1746,7 +1746,7 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
 		ret = f2fs_do_sync_file(filp, 0, LLONG_MAX, 1, false);
 	}
 err_out:
-	up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	inode_unlock(inode);
 	mnt_drop_write_file(filp);
 	return ret;
@@ -2333,12 +2333,12 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in,
 	}
 
 	inode_lock(src);
-	down_write(&F2FS_I(src)->dio_rwsem[WRITE]);
+	down_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
 	if (src != dst) {
 		ret = -EBUSY;
 		if (!inode_trylock(dst))
 			goto out;
-		if (!down_write_trylock(&F2FS_I(dst)->dio_rwsem[WRITE])) {
+		if (!down_write_trylock(&F2FS_I(dst)->i_gc_rwsem[WRITE])) {
 			inode_unlock(dst);
 			goto out;
 		}
@@ -2400,11 +2400,11 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in,
 	f2fs_unlock_op(sbi);
 out_unlock:
 	if (src != dst) {
-		up_write(&F2FS_I(dst)->dio_rwsem[WRITE]);
+		up_write(&F2FS_I(dst)->i_gc_rwsem[WRITE]);
 		inode_unlock(dst);
 	}
 out:
-	up_write(&F2FS_I(src)->dio_rwsem[WRITE]);
+	up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
 	inode_unlock(src);
 	return ret;
 }
@@ -2814,9 +2814,9 @@ int f2fs_precache_extents(struct inode *inode)
 	while (map.m_lblk < end) {
 		map.m_len = end - map.m_lblk;
 
-		down_write(&fi->dio_rwsem[WRITE]);
+		down_write(&fi->i_gc_rwsem[WRITE]);
 		err = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_PRECACHE);
-		up_write(&fi->dio_rwsem[WRITE]);
+		up_write(&fi->i_gc_rwsem[WRITE]);
 		if (err)
 			return err;
 
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index a7de8b34..94746d5 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -858,7 +858,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			}
 
 			if (!down_write_trylock(
-				&F2FS_I(inode)->dio_rwsem[WRITE])) {
+				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
 				iput(inode);
 				continue;
 			}
@@ -867,7 +867,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			data_page = get_read_data_page(inode,
 					start_bidx + ofs_in_node, REQ_RAHEAD,
 					true);
-			up_write(&F2FS_I(inode)->dio_rwsem[WRITE]);
+			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 			if (IS_ERR(data_page)) {
 				iput(inode);
 				continue;
@@ -885,11 +885,11 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 			bool locked = false;
 
 			if (S_ISREG(inode->i_mode)) {
-				if (!down_write_trylock(&fi->dio_rwsem[READ]))
+				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
 					continue;
 				if (!down_write_trylock(
-						&fi->dio_rwsem[WRITE])) {
-					up_write(&fi->dio_rwsem[READ]);
+						&fi->i_gc_rwsem[WRITE])) {
+					up_write(&fi->i_gc_rwsem[READ]);
 					continue;
 				}
 				locked = true;
@@ -907,8 +907,8 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 								segno, off);
 
 			if (locked) {
-				up_write(&fi->dio_rwsem[WRITE]);
-				up_write(&fi->dio_rwsem[READ]);
+				up_write(&fi->i_gc_rwsem[WRITE]);
+				up_write(&fi->i_gc_rwsem[READ]);
 			}
 
 			stat_inc_data_blk_count(sbi, 1, gc_type);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 5b03041..baab473 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -837,8 +837,8 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
 	INIT_LIST_HEAD(&fi->inmem_ilist);
 	INIT_LIST_HEAD(&fi->inmem_pages);
 	mutex_init(&fi->inmem_lock);
-	init_rwsem(&fi->dio_rwsem[READ]);
-	init_rwsem(&fi->dio_rwsem[WRITE]);
+	init_rwsem(&fi->i_gc_rwsem[READ]);
+	init_rwsem(&fi->i_gc_rwsem[WRITE]);
 	init_rwsem(&fi->i_mmap_sem);
 	init_rwsem(&fi->i_xattr_sem);