[RFC][PATCH 11/30] r/o bind mounts: elevate write count for callers of vfs_mkdir()

Dave Hansen
2008-02-08T22:31:42Z

Pretty self-explanatory. Fits in with the rest of the series.

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---

linux-2.6.git-dave/fs/namei.c | 5 +++++
linux-2.6.git-dave/fs/nfsd/nfs4recover.c | 5 +++++
2 files changed, 10 insertions(+)

diff -puN fs/namei.c~r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir fs/namei.c
--- linux-2.6.git/fs/namei.c~r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir 2008-02-08 13:04:50.000000000 -0800
+++ linux-2.6.git-dave/fs/namei.c 2008-02-08 13:04:50.000000000 -0800
@@ -2080,7 +2080,12 @@ asmlinkage long sys_mkdirat(int dfd, con

if (!IS_POSIXACL(nd.dentry->d_inode))
mode &= ~current->fs->umask;
+ error = mnt_want_write(nd.mnt);
+ if (error)
+ goto out_dput;
error = vfs_mkdir(nd.dentry->d_inode, dentry, mode);
+ mnt_drop_write(nd.mnt);
+out_dput:
dput(dentry);
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
diff -puN fs/nfsd/nfs4recover.c~r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir fs/nfsd/nfs4recover.c
--- linux-2.6.git/fs/nfsd/nfs4recover.c~r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir 2008-02-08 13:04:50.000000000 -0800
+++ linux-2.6.git-dave/fs/nfsd/nfs4recover.c 2008-02-08 13:04:50.000000000 -0800
@@ -41,6 +41,7 @@
#include <linux/nfsd/xdr4.h>
#include <linux/param.h>
#include <linux/file.h>
+#include <linux/mount.h>
#include <linux/namei.h>
#include <asm/uaccess.h>
#include <linux/scatterlist.h>
@@ -154,7 +155,11 @@ nfsd4_create_clid_dir(struct nfs4_client
dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
goto out_put;
}
+ status = mnt_want_write(rec_dir.mnt);
+ if (status)
+ goto out_put;
status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
+ mnt_drop_write(rec_dir.mnt);
out_put:
dput(dentry);
out_unlock:
_