Commit 02b9984d authored Mar 13, 2014 by Theodore Ts'o

fs: push sync_filesystem() down to the file system's remount_fs()



Previously, the no-op "mount -o mount /dev/xxx" operation when the
file system is already mounted read-write causes an implied,
unconditional syncfs().  This seems pretty stupid, and it's certainly
documented or guaraunteed to do this, nor is it particularly useful,
except in the case where the file system was mounted rw and is getting
remounted read-only.

However, it's possible that there might be some file systems that are
actually depending on this behavior.  In most file systems, it's
probably fine to only call sync_filesystem() when transitioning from
read-write to read-only, and there are some file systems where this is
not needed at all (for example, for a pseudo-filesystem or something
like romfs).

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Anders Larsen <al@alarsen.net>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: xfs@oss.sgi.com
Cc: linux-btrfs@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: codalist@coda.cs.cmu.edu
Cc: linux-ext4@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: fuse-devel@lists.sourceforge.net
Cc: cluster-devel@redhat.com
Cc: linux-mtd@lists.infradead.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: linux-nfs@vger.kernel.org
Cc: linux-nilfs@vger.kernel.org
Cc: linux-ntfs-dev@lists.sourceforge.net
Cc: ocfs2-devel@oss.oracle.com
Cc: reiserfs-devel@vger.kernel.org

parent 66a4cb18

fs/adfs/super.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -212,6 +212,7 @@ static int parse_options(struct super_block sb, char options)

		static int adfs_remount(struct super_block sb, int flags, char *data)
		{
		sync_filesystem(sb);
		*flags \|= MS_NODIRATIME;
		return parse_options(sb, data);
		}

fs/affs/super.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -530,6 +530,7 @@ affs_remount(struct super_block sb, int flags, char *data)

		pr_debug("AFFS: remount(flags=0x%x,opts=\"%s\")\n",*flags,data);

		sync_filesystem(sb);
		*flags \|= MS_NODIRATIME;

		memcpy(volume, sbi->s_volume, 32);

fs/befs/linuxvfs.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -913,6 +913,7 @@ befs_fill_super(struct super_block sb, void data, int silent)
		static int
		befs_remount(struct super_block sb, int flags, char *data)
		{
		sync_filesystem(sb);
		if (!(*flags & MS_RDONLY))
		return -EINVAL;
		return 0;

fs/btrfs/super.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1381,6 +1381,7 @@ static int btrfs_remount(struct super_block sb, int flags, char *data)
		unsigned int old_metadata_ratio = fs_info->metadata_ratio;
		int ret;

		sync_filesystem(sb);
		btrfs_remount_prepare(fs_info);

		ret = btrfs_parse_options(root, data);

fs/cifs/cifsfs.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -541,6 +541,7 @@ static int cifs_show_stats(struct seq_file s, struct dentry root)

		static int cifs_remount(struct super_block sb, int flags, char *data)
		{
		sync_filesystem(sb);
		*flags \|= MS_NODIRATIME;
		return 0;
		}

Admin message