linux-kernel - [RFC PATCH 2/6] romfs: Convert to fs

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Message-ID: <155316913726.30162.6525923674606267530.stgit@warthog.procyon.org.uk>
Date:   Thu, 21 Mar 2019 11:52:17 +0000
From:   David Howells <dhowells@...hat.com>
To:     viro@...iv.linux.org.uk
Cc:     linux-mtd@...ts.infradead.org, linux-block@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        dhowells@...hat.com
Subject: [RFC PATCH 2/6] romfs: Convert to fs_context

Signed-off-by: David Howells <dhowells@...hat.com>
cc: linux-mtd@...ts.infradead.org
cc: linux-block@...r.kernel.org
---

 fs/romfs/super.c |   46 ++++++++++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/fs/romfs/super.c b/fs/romfs/super.c
index 6ccb51993a76..627c2b64ff03 100644
--- a/fs/romfs/super.c
+++ b/fs/romfs/super.c
@@ -65,7 +65,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
-#include <linux/parser.h>
+#include <linux/fs_context.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
 #include <linux/statfs.h>
@@ -430,10 +430,10 @@ static int romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 /*
  * remounting must involve read-only
  */
-static int romfs_remount(struct super_block *sb, int *flags, char *data)
+static int romfs_reconfigure(struct fs_context *fc)
 {
-	sync_filesystem(sb);
-	*flags |= SB_RDONLY;
+	sync_filesystem(fc->root->d_sb);
+	fc->sb_flags |= SB_RDONLY;
 	return 0;
 }
 
@@ -441,7 +441,6 @@ static const struct super_operations romfs_super_ops = {
 	.alloc_inode	= romfs_alloc_inode,
 	.destroy_inode	= romfs_destroy_inode,
 	.statfs		= romfs_statfs,
-	.remount_fs	= romfs_remount,
 };
 
 /*
@@ -464,7 +463,7 @@ static __u32 romfs_checksum(const void *data, int size)
 /*
  * fill in the superblock
  */
-static int romfs_fill_super(struct super_block *sb, void *data, int silent)
+static int romfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct romfs_super_block *rsb;
 	struct inode *root;
@@ -511,8 +510,8 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1 ||
 	    img_size < ROMFH_SIZE) {
-		if (!silent)
-			pr_warn("VFS: Can't find a romfs filesystem on dev %s.\n",
+		if (!(fc->sb_flags & SB_SILENT))
+			errorf(fc, "VFS: Can't find a romfs filesystem on dev %s.\n",
 			       sb->s_id);
 		goto error_rsb_inval;
 	}
@@ -525,7 +524,7 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 	storage = sb->s_mtd ? "MTD" : "the block layer";
 
 	len = strnlen(rsb->name, ROMFS_MAXFN);
-	if (!silent)
+	if (!(fc->sb_flags & SB_SILENT))
 		pr_notice("Mounting image '%*.*s' through %s\n",
 			  (unsigned) len, (unsigned) len, rsb->name, storage);
 
@@ -555,23 +554,34 @@ static int romfs_fill_super(struct super_block *sb, void *data, int silent)
 /*
  * get a superblock for mounting
  */
-static struct dentry *romfs_mount(struct file_system_type *fs_type,
-			int flags, const char *dev_name,
-			void *data)
+static int romfs_get_tree(struct fs_context *fc)
 {
-	struct dentry *ret = ERR_PTR(-EINVAL);
+	int ret = -EINVAL;
 
 #ifdef CONFIG_ROMFS_ON_MTD
-	ret = mount_mtd(fs_type, flags, dev_name, data, romfs_fill_super);
+	ret = vfs_get_mtd_super(fc, romfs_fill_super);
 #endif
 #ifdef CONFIG_ROMFS_ON_BLOCK
-	if (ret == ERR_PTR(-EINVAL))
-		ret = mount_bdev(fs_type, flags, dev_name, data,
-				  romfs_fill_super);
+	if (ret == -EINVAL)
+		ret = vfs_get_block_super(fc, romfs_fill_super);
 #endif
 	return ret;
 }
 
+static const struct fs_context_operations romfs_context_ops = {
+	.get_tree	= romfs_get_tree,
+	.reconfigure	= romfs_reconfigure,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int romfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &romfs_context_ops;
+	return 0;
+}
+
 /*
  * destroy a romfs superblock in the appropriate manner
  */
@@ -594,7 +604,7 @@ static void romfs_kill_sb(struct super_block *sb)
 static struct file_system_type romfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "romfs",
-	.mount		= romfs_mount,
+	.init_fs_context = romfs_init_fs_context,
 	.kill_sb	= romfs_kill_sb,
 	.fs_flags	= FS_REQUIRES_DEV,
 };