X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;ds=sidebyside;f=fs%2Fnfs%2Fgetroot.c;h=fae97196daadb74c1dd1c28a5767460557402478;hb=4c54ac62dceecedd82d4a865017bba0b738e2897;hp=6ef268f7c300a2458a74e4292efec297b21de3b0;hpb=faebf4e2bb0efad9dda396ea13d5c6ad15d7d7fb;p=safe%2Fjmp%2Flinux-2.6

diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index 6ef268f..fae9719 100644
--- a/fs/nfs/getroot.c
+++ b/fs/nfs/getroot.c
@@ -25,7 +25,6 @@
 #include <linux/nfs_mount.h>
 #include <linux/nfs4_mount.h>
 #include <linux/lockd/bind.h>
-#include <linux/smp_lock.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
 #include <linux/nfs_idmap.h>
@@ -42,7 +41,36 @@
 #include "internal.h"
 
 #define NFSDBG_FACILITY		NFSDBG_CLIENT
-#define NFS_PARANOIA 1
+
+/*
+ * 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);
+		/*
+		 * Ensure that this dentry is invisible to d_find_alias().
+		 * Otherwise, it may be spliced into the tree by
+		 * d_materialise_unique if a parent directory from the same
+		 * filesystem gets mounted at a later time.
+		 * This again causes shrink_dcache_for_umount_subtree() to
+		 * Oops, since the test for IS_ROOT() will fail.
+		 */
+		spin_lock(&dcache_lock);
+		list_del_init(&sb->s_root->d_alias);
+		spin_unlock(&dcache_lock);
+	}
+	return 0;
+}
 
 /*
  * get an NFS2/NFS3 root dentry from the root filehandle
@@ -56,33 +84,6 @@ 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;
 
@@ -95,9 +96,13 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 	inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
 	if (IS_ERR(inode)) {
 		dprintk("nfs_get_root: get root inode failed\n");
-		return ERR_PTR(PTR_ERR(inode));
+		return ERR_CAST(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
@@ -177,6 +182,9 @@ next_component:
 		path++;
 	name.len = path - (const char *) name.name;
 
+	if (name.len > NFS4_MAXNAMLEN)
+		return -ENAMETOOLONG;
+
 eat_dot_dir:
 	while (*path == '/')
 		path++;
@@ -240,33 +248,6 @@ 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) {
@@ -285,9 +266,13 @@ struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
 	inode = nfs_fhget(sb, mntfh, &fattr);
 	if (IS_ERR(inode)) {
 		dprintk("nfs_get_root: get root inode failed\n");
-		return ERR_PTR(PTR_ERR(inode));
+		return ERR_CAST(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