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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-10-25 21:56:10 +0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-11-17 21:08:44 +0300
commitb09b9417d074e01a4e4ab5c19358f1b3dc76c1b2 (patch)
treeed90c600222d35834b045e8a72336621d36f0b2e /fs/nfs/getroot.c
parent2ffbb8377c7a0713baf6644e285adc27a5654582 (diff)
downloadlinux-b09b9417d074e01a4e4ab5c19358f1b3dc76c1b2.tar.xz
NFS: Fix the ustat() regression
Since 2.6.18, the superblock sb->s_root has been a dummy dentry with a dummy inode. This breaks ustat(), which actually uses sb->s_root in a vfstat() call. Fix this by making the s_root a dummy alias to the directory inode that was used when creating the superblock. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/getroot.c')
-rw-r--r--fs/nfs/getroot.c81
1 files changed, 27 insertions, 54 deletions
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index 522e5ad4d8ad..0ee43843f4ec 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -43,6 +43,25 @@
#define NFSDBG_FACILITY NFSDBG_CLIENT
/*
+ * Set the superblock root dentry.
+ * Note that this function frees the inode in case of error.
+ */
+static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
+{
+ /* The mntroot acts as the dummy root dentry for this superblock */
+ if (sb->s_root == NULL) {
+ sb->s_root = d_alloc_root(inode);
+ if (sb->s_root == NULL) {
+ iput(inode);
+ return -ENOMEM;
+ }
+ /* Circumvent igrab(): we know the inode is not being freed */
+ atomic_inc(&inode->i_count);
+ }
+ return 0;
+}
+
+/*
* get an NFS2/NFS3 root dentry from the root filehandle
*/
struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
@@ -54,33 +73,6 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
struct inode *inode;
int error;
- /* create a dummy root dentry with dummy inode for this superblock */
- if (!sb->s_root) {
- struct nfs_fh dummyfh;
- struct dentry *root;
- struct inode *iroot;
-
- memset(&dummyfh, 0, sizeof(dummyfh));
- memset(&fattr, 0, sizeof(fattr));
- nfs_fattr_init(&fattr);
- fattr.valid = NFS_ATTR_FATTR;
- fattr.type = NFDIR;
- fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR;
- fattr.nlink = 2;
-
- iroot = nfs_fhget(sb, &dummyfh, &fattr);
- if (IS_ERR(iroot))
- return ERR_PTR(PTR_ERR(iroot));
-
- root = d_alloc_root(iroot);
- if (!root) {
- iput(iroot);
- return ERR_PTR(-ENOMEM);
- }
-
- sb->s_root = root;
- }
-
/* get the actual root for this mount */
fsinfo.fattr = &fattr;
@@ -96,6 +88,10 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
return ERR_PTR(PTR_ERR(inode));
}
+ error = nfs_superblock_set_dummy_root(sb, inode);
+ if (error != 0)
+ return ERR_PTR(error);
+
/* root dentries normally start off anonymous and get spliced in later
* if the dentry tree reaches them; however if the dentry already
* exists, we'll pick it up at this point and use it as the root
@@ -241,33 +237,6 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
dprintk("--> nfs4_get_root()\n");
- /* create a dummy root dentry with dummy inode for this superblock */
- if (!sb->s_root) {
- struct nfs_fh dummyfh;
- struct dentry *root;
- struct inode *iroot;
-
- memset(&dummyfh, 0, sizeof(dummyfh));
- memset(&fattr, 0, sizeof(fattr));
- nfs_fattr_init(&fattr);
- fattr.valid = NFS_ATTR_FATTR;
- fattr.type = NFDIR;
- fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR;
- fattr.nlink = 2;
-
- iroot = nfs_fhget(sb, &dummyfh, &fattr);
- if (IS_ERR(iroot))
- return ERR_PTR(PTR_ERR(iroot));
-
- root = d_alloc_root(iroot);
- if (!root) {
- iput(iroot);
- return ERR_PTR(-ENOMEM);
- }
-
- sb->s_root = root;
- }
-
/* get the info about the server and filesystem */
error = nfs4_server_capabilities(server, mntfh);
if (error < 0) {
@@ -289,6 +258,10 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
return ERR_PTR(PTR_ERR(inode));
}
+ error = nfs_superblock_set_dummy_root(sb, inode);
+ if (error != 0)
+ return ERR_PTR(error);
+
/* root dentries normally start off anonymous and get spliced in later
* if the dentry tree reaches them; however if the dentry already
* exists, we'll pick it up at this point and use it as the root