[PATCH] r/o bind mounts: elevate write count for rmdir and unlink.

Elevate the write count during the vfs_rmdir() and vfs_unlink().

[AV: merged rmdir and unlink parts, added missing pieces in nfsd]

Acked-by: Serge Hallyn <serue@us.ibm.com>
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>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 46f59d5365a0..efff58a5818c 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1750,6 +1750,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
         if (!type)
                 type = rdentry->d_inode->i_mode & S_IFMT;
 
+        host_err = mnt_want_write(fhp->fh_export->ex_path.mnt);
+        if (host_err)
+                goto out_nfserr;
+
         if (type != S_IFDIR) { /* It's UNLINK */
 #ifdef MSNFS
                 if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
@@ -1765,10 +1769,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
         dput(rdentry);
 
         if (host_err)
-                goto out_nfserr;
+                goto out_drop;
         if (EX_ISSYNC(fhp->fh_export))
                 host_err = nfsd_sync_dir(dentry);
 
+out_drop:
+        mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
         err = nfserrno(host_err);
 out: