lkml.org 
[lkml]   [2008]   [Feb]   [8]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[RFC][PATCH 09/30] r/o bind mounts: drop write during emergency remount
FromDave Hansen <>
DateFri, 08 Feb 2008 14:26:58 -0800
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.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---
 linux-2.6.git-dave/fs/super.c |   20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)
diff -puN fs/super.c~robind-sysrq-fix fs/super.c
--- linux-2.6.git/fs/super.c~robind-sysrq-fix	2008-02-08 13:04:48.000000000 -0800
+++ linux-2.6.git-dave/fs/super.c	2008-02-08 13:04:49.000000000 -0800
@@ -37,6 +37,7 @@
 #include <linux/idr.h>
 #include <linux/kobject.h>
 #include <linux/mutex.h>
+#include <linux/file.h>
 #include <asm/uaccess.h>
 
 
@@ -566,10 +567,25 @@ static void mark_files_ro(struct super_b
 {
 	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))
-			f->f_mode &= ~FMODE_WRITE;
+		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 = f->f_path.mnt;
+		file_list_unlock();
+		/*
+		 * This can sleep, so we can't hold
+		 * the file_list_lock() spinlock.
+		 */
+		mnt_drop_write(mnt);
+		goto retry;
 	}
 	file_list_unlock();
 }
_

\
 
 \ /
  Last update: 2008-02-08 23:35    [from the cache]
©2003-2008