linux-kernel - [RFC][PATCH 11/30] r/o bind mounts: elevate write count for callers of vfs

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Message-Id: <20080208222701.8397FA69@kernel>
Date:	Fri, 08 Feb 2008 14:27:01 -0800
From:	Dave Hansen <haveblue@...ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	hch@....de, viro@...IV.linux.org.uk, viro@....linux.org.uk,
	miklos@...redi.hu, Dave Hansen <haveblue@...ibm.com>
Subject: [RFC][PATCH 11/30] r/o bind mounts: elevate write count for callers of vfs_mkdir()


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

Acked-by: Christoph Hellwig <hch@...radead.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Dave Hansen <haveblue@...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:
_
--
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