Commit 49e0d02c authored by Dave Hansen's avatar Dave Hansen Committed by Al Viro
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[PATCH] r/o bind mounts: drop write during emergency remount 



The emergency remount code forcibly removes FMODE_WRITE from
filps.  The r/o bind mount code notices that this was done
without a proper mnt_drop_write() and properly gives a
warning.

This patch does a mnt_drop_write() to keep everything
balanced.

Acked-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent aceaf78d

fs/super.c

+19 −2
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/idr.h>

#include <linux/kobject.h>

#include <linux/mutex.h>

#include <linux/file.h>

#include <asm/uaccess.h>
@@ -567,10 +568,26 @@ static void mark_files_ro(struct super_block *sb) 
{

	struct file *f;



retry:

	file_list_lock();

	list_for_each_entry(f, &sb->s_files, f_u.fu_list) {

		if (S_ISREG(f->f_path.dentry->d_inode->i_mode) && file_count(f))

		struct vfsmount *mnt;

		if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))

		       continue;

		if (!file_count(f))

			continue;

		if (!(f->f_mode & FMODE_WRITE))

			continue;

		f->f_mode &= ~FMODE_WRITE;

		mnt = mntget(f->f_path.mnt);

		file_list_unlock();

		/*

		 * This can sleep, so we can't hold

		 * the file_list_lock() spinlock.

		 */

		mnt_drop_write(mnt);

		mntput(mnt);

		goto retry;

	}

	file_list_unlock();

}