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[PATCH] r/o bind mounts: elevate write count for ioctls()

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Some ioctl()s can cause writes to the filesystem.  Take these, and make them
use mnt_want/drop_write() instead.

[AV: updated]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dave Hansen
2008-02-15 14:37:46 -08:00
committed by Al Viro
parent 20ddee2c75
commit 42a74f206b
9 changed files with 264 additions and 154 deletions
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12
fs/fat/file.c
View File

@@ -8,6 +8,7 @@
#include <linux/capability.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/time.h>
#include <linux/msdos_fs.h>
#include <linux/smp_lock.h>
@@ -46,10 +47,9 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
mutex_lock(&inode->i_mutex);
if (IS_RDONLY(inode)) {
err = -EROFS;
goto up;
}
err = mnt_want_write(filp->f_path.mnt);
if (err)
goto up_no_drop_write;
/*
* ATTR_VOLUME and ATTR_DIR cannot be changed; this also
@@ -105,7 +105,9 @@ int fat_generic_ioctl(struct inode *inode, struct file *filp,
MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
mark_inode_dirty(inode);
up:
up:
mnt_drop_write(filp->f_path.mnt);
up_no_drop_write:
mutex_unlock(&inode->i_mutex);
return err;
}