Commit 62a877e3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Niv Sardi
Browse files

[XFS] fix mount option parsing in remount 



Remount currently happily accept any option thrown at it, although the
only filesystem specific option it actually handles is barrier/nobarrier.
And it actually doesn't handle these correctly either because it only uses
the value it parsed when we're doing a ro->rw transition. In addition to
that there's also a bad bug in xfs_parseargs which doesn't touch the
actual option in the mount point except for a single one,
XFS_MOUNT_SMALL_INUMS and thus forced any filesystem that's every
remounted in some way to not support 64bit inodes with no way to recover
unless unmounted.

This patch changes xfs_fs_remount to use it's own linux/parser.h based
options parse instead of xfs_parseargs and reject all options except for
barrier/nobarrier and to the right thing in general. Eventually I'd like
to have a single big option table used for mount aswell but that can wait
for a while.

SGI-PV: 983964

SGI-Modid: xfs-linux-melb:xfs-kern:31382a

Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent deeb5912

fs/xfs/linux-2.6/xfs_super.c

+54 −18
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ 
#include <linux/writeback.h>

#include <linux/kthread.h>

#include <linux/freezer.h>

#include <linux/parser.h>



static struct quotactl_ops xfs_quotactl_operations;

static struct super_operations xfs_super_operations;
@@ -147,6 +148,23 @@ xfs_args_allocate( 
#define MNTOPT_XDSM	"xdsm"		/* DMI enabled (DMAPI / XDSM) */

#define MNTOPT_DMI	"dmi"		/* DMI enabled (DMAPI / XDSM) */



/*

 * Table driven mount option parser.

 *

 * Currently only used for remount, but it will be used for mount

 * in the future, too.

 */

enum {

	Opt_barrier, Opt_nobarrier, Opt_err

};



static match_table_t tokens = {

	{Opt_barrier, "barrier"},

	{Opt_nobarrier, "nobarrier"},

	{Opt_err, NULL}

};





STATIC unsigned long

suffix_strtoul(char *s, char **endp, unsigned int base)

{
@@ -1364,36 +1382,54 @@ xfs_fs_remount( 
	char			*options)

{

	struct xfs_mount	*mp = XFS_M(sb);

	struct xfs_mount_args	*args;

	int			error;

	substring_t		args[MAX_OPT_ARGS];

	char			*p;



	args = xfs_args_allocate(sb, 0);

	if (!args)

		return -ENOMEM;

	while ((p = strsep(&options, ",")) != NULL) {

		int token;



	error = xfs_parseargs(mp, options, args, 1);

	if (error)

		goto out_free_args;

		if (!*p)

			continue;



	if (!(*flags & MS_RDONLY)) {			/* rw/ro -> rw */

		if (mp->m_flags & XFS_MOUNT_RDONLY)

		mp->m_flags &= ~XFS_MOUNT_RDONLY;

		if (args->flags & XFSMNT_BARRIER) {

		token = match_token(p, tokens, args);

		switch (token) {

		case Opt_barrier:

			mp->m_flags |= XFS_MOUNT_BARRIER;



			/*

			 * Test if barriers are actually working if we can,

			 * else delay this check until the filesystem is

			 * marked writeable.

			 */

			if (!(mp->m_flags & XFS_MOUNT_RDONLY))

				xfs_mountfs_check_barriers(mp);

		} else {

			break;

		case Opt_nobarrier:

			mp->m_flags &= ~XFS_MOUNT_BARRIER;

			break;

		default:

			printk(KERN_INFO

	"XFS: mount option \"%s\" not supported for remount\n", p);

			return -EINVAL;

		}

	}

	} else if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {	/* rw -> ro */



	/* rw/ro -> rw */

	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & MS_RDONLY)) {

		mp->m_flags &= ~XFS_MOUNT_RDONLY;

		if (mp->m_flags & XFS_MOUNT_BARRIER)

			xfs_mountfs_check_barriers(mp);

	}



	/* rw -> ro */

	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & MS_RDONLY)) {

		xfs_filestream_flush(mp);

		xfs_sync(mp, SYNC_DATA_QUIESCE);

		xfs_attr_quiesce(mp);

		mp->m_flags |= XFS_MOUNT_RDONLY;

	}



 out_free_args:

	kfree(args);

	return -error;

	return 0;

}



/*

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