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authorDave Hansen <haveblue@us.ibm.com>2007-10-16 23:31:14 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:43:05 -0700
commitb41572e929221b0d87f529106cdf12185ee84bca (patch)
tree0ffd9252f53e9e964e962d6d428377851f12b015 /fs/namei.c
parentce8d2cdf3d2b73e346c82e6f0a46da331df6364c (diff)
r/o bind mounts: rearrange may_open() to be r/o friendly
may_open() calls vfs_permission() before it does checks for IS_RDONLY(inode). It checks _again_ inside of vfs_permission(). The check inside of vfs_permission() is going away eventually. With the mnt_want/drop_write() functions, all of the r/o checks (except for this one) are consistently done before calling permission(). Because of this, I'd like to use permission() to hold a debugging check to make sure that the mnt_want/drop_write() calls are actually being made. So, to do this: 1. remove the IS_RDONLY() check from permission() 2. enforce that you must mnt_want_write() before even calling permission() 3. actually add the debugging check to permission() We need to rearrange may_open() to do r/o checks before calling permission(). Here's the patch. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 2792e0ca01d4..a29bb0f40ed5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1604,10 +1604,6 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE))
return -EISDIR;
- error = vfs_permission(nd, acc_mode);
- if (error)
- return error;
-
/*
* FIFO's, sockets and device files are special: they don't
* actually live on the filesystem itself, and as such you
@@ -1622,6 +1618,10 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
flag &= ~O_TRUNC;
} else if (IS_RDONLY(inode) && (flag & FMODE_WRITE))
return -EROFS;
+
+ error = vfs_permission(nd, acc_mode);
+ if (error)
+ return error;
/*
* An append-only file must be opened in append mode for writing.
*/