diff options
| author | Dave Hansen <haveblue@us.ibm.com> | 2008-02-15 14:37:55 -0800 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2008-04-19 00:29:26 -0400 |
| commit | 2f676cbc0d60ae806216c7a61c6971bd72dedde8 (patch) | |
| tree | 57287366150093260f18bdbe81596492e3e40aa1 /fs/open.c | |
| parent | 9ac9b8474c39c3ae2c2b37d8e1f08db8a9146124 (diff) | |
| download | lwn-2f676cbc0d60ae806216c7a61c6971bd72dedde8.tar.gz lwn-2f676cbc0d60ae806216c7a61c6971bd72dedde8.zip | |
[PATCH] r/o bind mounts: make access() use new r/o helper
It is OK to let access() go without using a mnt_want/drop_write() pair because
it doesn't actually do writes to the filesystem, and it is inherently racy
anyway. This is a rare case when it is OK to use __mnt_is_readonly()
directly.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
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>
Diffstat (limited to 'fs/open.c')
| -rw-r--r-- | fs/open.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/open.c b/fs/open.c index 4d690e33446f..e58382d57e72 100644 --- a/fs/open.c +++ b/fs/open.c @@ -459,8 +459,17 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode) if(res || !(mode & S_IWOTH) || special_file(nd.path.dentry->d_inode->i_mode)) goto out_path_release; - - if(IS_RDONLY(nd.path.dentry->d_inode)) + /* + * This is a rare case where using __mnt_is_readonly() + * is OK without a mnt_want/drop_write() pair. Since + * no actual write to the fs is performed here, we do + * not need to telegraph to that to anyone. + * + * By doing this, we accept that this access is + * inherently racy and know that the fs may change + * state before we even see this result. + */ + if (__mnt_is_readonly(nd.path.mnt)) res = -EROFS; out_path_release: |