[FOR INTERNAL REVIEW] [PATCH RESEND 4/4] staging: erofs: update .mount and .remount_sb

[Gao Xiang]

This patch updates .mount and .remount_sb after
commit 286c6b145729 ("vfs: Require specification
of size of mount data for internal mounts").

Reported-by: Stephen Rothwell <sfr at canb.auug.org.au>
Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
---

- Tested with images generated by mkfs.erofs:
   1) mount and unmount operations
   2) md5sum `find . -type f`

 drivers/staging/erofs/internal.h |  1 -
 drivers/staging/erofs/super.c    | 61 +++++++++++-----------------------------
 2 files changed, 16 insertions(+), 46 deletions(-)

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 367b39f..9074a56 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -111,7 +111,6 @@ struct erofs_sb_info {
 
 	u8 uuid[16];                    /* 128-bit uuid for volume */
 	u8 volume_name[16];             /* volume name */
-	char *dev_name;
 
 	unsigned int mount_opt;
 	unsigned int shrinker_run_no;
diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
index ae1eb20..190a538 100644
--- a/drivers/staging/erofs/super.c
+++ b/drivers/staging/erofs/super.c
@@ -313,14 +313,18 @@ static struct inode *erofs_init_managed_cache(struct super_block *sb)
 
 #endif
 
-static int erofs_read_super(struct super_block *sb,
-	const char *dev_name, void *data, int silent)
+static int erofs_read_super(struct super_block *sb, void *data,
+			    size_t data_size, int silent)
 {
 	struct inode *inode;
 	struct erofs_sb_info *sbi;
+	char b[BDEVNAME_SIZE];
 	int err = -EINVAL;
 
-	infoln("read_super, device -> %s", dev_name);
+	/* get the block device name */
+	bdevname(sb->s_bdev, b);
+
+	infoln("read_super, device -> %s", b);
 	infoln("options -> %s", (char *)data);
 
 	if (unlikely(!sb_set_blocksize(sb, EROFS_BLKSIZ))) {
@@ -392,16 +396,6 @@ static int erofs_read_super(struct super_block *sb,
 		goto err_makeroot;
 	}
 
-	/* save the device name to sbi */
-	sbi->dev_name = __getname();
-	if (sbi->dev_name == NULL) {
-		err = -ENOMEM;
-		goto err_devname;
-	}
-
-	snprintf(sbi->dev_name, PATH_MAX, "%s", dev_name);
-	sbi->dev_name[PATH_MAX - 1] = '\0';
-
 	erofs_register_super(sb);
 
 	/*
@@ -411,15 +405,13 @@ static int erofs_read_super(struct super_block *sb,
 	d_rehash(sb->s_root);
 
 	if (!silent)
-		infoln("mounted on %s with opts: %s.", dev_name,
-			(char *)data);
+		infoln("mounted on %s with opts: %s.", b, (char *)data);
 	return 0;
 	/*
 	 * please add a label for each exit point and use
 	 * the following name convention, thus new features
 	 * can be integrated easily without renaming labels.
 	 */
-err_devname:
 	dput(sb->s_root);
 err_makeroot:
 err_isdir:
@@ -445,6 +437,7 @@ static int erofs_read_super(struct super_block *sb,
 static void erofs_put_super(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	char b[BDEVNAME_SIZE];
 
 	/* for cases which are failed in "read_super" */
 	if (sbi == NULL)
@@ -452,8 +445,7 @@ static void erofs_put_super(struct super_block *sb)
 
 	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
 
-	infoln("unmounted for %s", sbi->dev_name);
-	__putname(sbi->dev_name);
+	infoln("unmounted for %s", bdevname(sb->s_bdev, b));
 
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
 	iput(sbi->managed_cache);
@@ -472,33 +464,11 @@ static void erofs_put_super(struct super_block *sb)
 	sb->s_fs_info = NULL;
 }
 
-
-struct erofs_mount_private {
-	const char *dev_name;
-	char *options;
-};
-
-/* support mount_bdev() with options */
-static int erofs_fill_super(struct super_block *sb,
-	void *_priv, int silent)
-{
-	struct erofs_mount_private *priv = _priv;
-
-	return erofs_read_super(sb, priv->dev_name,
-		priv->options, silent);
-}
-
-static struct dentry *erofs_mount(
-	struct file_system_type *fs_type, int flags,
-	const char *dev_name, void *data)
+static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags,
+	const char *dev_name, void *data, size_t data_size)
 {
-	struct erofs_mount_private priv = {
-		.dev_name = dev_name,
-		.options = data
-	};
-
-	return mount_bdev(fs_type, flags, dev_name,
-		&priv, erofs_fill_super);
+	return mount_bdev(fs_type, flags, dev_name, data, data_size,
+		erofs_read_super);
 }
 
 static void erofs_kill_sb(struct super_block *sb)
@@ -623,7 +593,8 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 	return 0;
 }
 
-static int erofs_remount(struct super_block *sb, int *flags, char *data)
+static int erofs_remount(struct super_block *sb, int *flags,
+	char *data, size_t data_size)
 {
 	BUG_ON(!sb_rdonly(sb));
 
-- 
1.9.1