[RFC][PATCH 23/27] elevate write count over calls to vfs_rename()

[Dave Hansen <haveblue@us.ibm.com>]

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---

 fs/xattr.c             |    0 
 lxc-dave/fs/namei.c    |   40 ++++++++++++++++++++++++++--------------
 lxc-dave/fs/nfsd/vfs.c |   12 +++++++++++-
 3 files changed, 37 insertions(+), 15 deletions(-)

diff -puN fs/namei.c~elevate-writers-vfs_rename-part1 fs/namei.c
--- lxc/fs/namei.c~elevate-writers-vfs_rename-part1	2006-06-07 16:53:26.000000000 -0700
+++ lxc-dave/fs/namei.c	2006-06-07 16:53:26.000000000 -0700
@@ -2507,29 +2507,37 @@ static int do_rename(int olddfd, const c
 	if (error)
 		goto exit;
 
-	error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd);
+	error = mnt_want_write(oldnd.mnt);
 	if (error)
 		goto exit1;
 
+	error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd);
+	if (error)
+		goto exit2;
+
+	error = mnt_want_write(oldnd.mnt);
+	if (error)
+		goto exit3;
+
 	error = -EXDEV;
 	if (oldnd.mnt != newnd.mnt)
-		goto exit2;
+		goto exit4;
 
 	old_dir = oldnd.dentry;
 	error = -EBUSY;
 	if (oldnd.last_type != LAST_NORM)
-		goto exit2;
+		goto exit4;
 
 	new_dir = newnd.dentry;
 	if (newnd.last_type != LAST_NORM)
-		goto exit2;
+		goto exit4;
 
 	trap = lock_rename(new_dir, old_dir);
 
 	old_dentry = lookup_hash(&oldnd);
 	error = PTR_ERR(old_dentry);
 	if (IS_ERR(old_dentry))
-		goto exit3;
+		goto exit5;
 	/* source must exist */
 	error = -ENOENT;
 	if (!old_dentry->d_inode)
@@ -2538,33 +2546,37 @@ static int do_rename(int olddfd, const c
 	if (!S_ISDIR(old_dentry->d_inode->i_mode)) {
 		error = -ENOTDIR;
 		if (oldnd.last.name[oldnd.last.len])
-			goto exit4;
+			goto exit6;
 		if (newnd.last.name[newnd.last.len])
-			goto exit4;
+			goto exit6;
 	}
 	/* source should not be ancestor of target */
 	error = -EINVAL;
 	if (old_dentry == trap)
-		goto exit4;
+		goto exit6;
 	new_dentry = lookup_hash(&newnd);
 	error = PTR_ERR(new_dentry);
 	if (IS_ERR(new_dentry))
-		goto exit4;
+		goto exit6;
 	/* target should not be an ancestor of source */
 	error = -ENOTEMPTY;
 	if (new_dentry == trap)
-		goto exit5;
+		goto exit7;
 
 	error = vfs_rename(old_dir->d_inode, old_dentry,
 				   new_dir->d_inode, new_dentry);
-exit5:
+exit7:
 	dput(new_dentry);
-exit4:
+exit6:
 	dput(old_dentry);
-exit3:
+exit5:
 	unlock_rename(new_dir, old_dir);
-exit2:
+exit4:
+	mnt_drop_write(newnd.mnt);
+exit3:
 	path_release(&newnd);
+exit2:
+	mnt_drop_write(oldnd.mnt);
 exit1:
 	path_release(&oldnd);
 exit:
diff -L ser -puN /dev/null /dev/null
diff -puN fs/ecryptfs/inode.c~elevate-writers-vfs_rename-part1 fs/ecryptfs/inode.c
diff -puN fs/nfsd/vfs.c~elevate-writers-vfs_rename-part1 fs/nfsd/vfs.c
--- lxc/fs/nfsd/vfs.c~elevate-writers-vfs_rename-part1	2006-06-07 16:53:26.000000000 -0700
+++ lxc-dave/fs/nfsd/vfs.c	2006-06-07 16:53:26.000000000 -0700
@@ -1601,13 +1601,23 @@ nfsd_rename(struct svc_rqst *rqstp, stru
 			err = -EPERM;
 	} else
 #endif
+	err = mnt_want_write(ffhp->fh_export->ex_mnt);
+	if (err)
+		goto out_dput_new;
+
+	err = mnt_want_write(tfhp->fh_export->ex_mnt);
+	if (err)
+		goto out_mnt_drop_write_old;
+
 	err = vfs_rename(fdir, odentry, tdir, ndentry);
 	if (!err && EX_ISSYNC(tfhp->fh_export)) {
 		err = nfsd_sync_dir(tdentry);
 		if (!err)
 			err = nfsd_sync_dir(fdentry);
 	}
-
+	mnt_drop_write(tfhp->fh_export->ex_mnt);
+ out_mnt_drop_write_old:
+	mnt_drop_write(ffhp->fh_export->ex_mnt);
  out_dput_new:
 	dput(ndentry);
  out_dput_old:
diff -puN fs/nfsd/nfsfh.c~elevate-writers-vfs_rename-part1 fs/nfsd/nfsfh.c
diff -puN fs/nfsd/nfs3proc.c~elevate-writers-vfs_rename-part1 fs/nfsd/nfs3proc.c
diff -puN fs/xattr.c~elevate-writers-vfs_rename-part1 fs/xattr.c
_