knfsd: exportfs: remove iget abuse

When the exportfs interface was added the expectation was that filesystems
provide an operation to convert from a file handle to an inode/dentry, but it
kept a backwards compat option that still calls into iget.

Calling into iget from non-filesystem code is very bad, because it gives too
little information to filesystem, and simply crashes if the filesystem doesn't
implement the ->read_inode routine.

Fortunately there are only two filesystems left using this fallback: efs and
jfs.  This patch moves a copy of export_iget to each of those to implement the
get_dentry method.

While this is a temporary increase of lines of code in the kernel it allows
for a much cleaner interface and important code restructuring in later
patches.

[akpm@linux-foundation.org: add jfs_get_inode_flags() declaration]
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/efs/namei.c b/fs/efs/namei.c
index ed4a207..5276b19 100644 (file)
--- a/fs/efs/namei.c
+++ b/fs/efs/namei.c
@@ -75,6 +75,38 @@ struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct namei
        return NULL;
 }
 
+struct dentry *efs_get_dentry(struct super_block *sb, void *vobjp)
+{
+       __u32 *objp = vobjp;
+       unsigned long ino = objp[0];
+       __u32 generation = objp[1];
+       struct inode *inode;
+       struct dentry *result;
+
+       if (ino == 0)
+               return ERR_PTR(-ESTALE);
+       inode = iget(sb, ino);
+       if (inode == NULL)
+               return ERR_PTR(-ENOMEM);
+
+       if (is_bad_inode(inode) ||
+           (generation && inode->i_generation != generation)) {
+               result = ERR_PTR(-ESTALE);
+               goto out_iput;
+       }
+
+       result = d_alloc_anon(inode);
+       if (!result) {
+               result = ERR_PTR(-ENOMEM);
+               goto out_iput;
+       }
+       return result;
+
+ out_iput:
+       iput(inode);
+       return result;
+}
+
 struct dentry *efs_get_parent(struct dentry *child)
 {
        struct dentry *parent;

diff --git a/fs/efs/super.c b/fs/efs/super.c
index 67338d6..d360c81 100644 (file)
--- a/fs/efs/super.c
+++ b/fs/efs/super.c
@@ -114,6 +114,7 @@ static const struct super_operations efs_superblock_operations = {
 };
 
 static struct export_operations efs_export_ops = {
+       .get_dentry     = efs_get_dentry,
        .get_parent     = efs_get_parent,
 };
 

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 16287af..dd132bb 100644 (file)
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -391,61 +391,11 @@ out:
        return error;
 }
 
-
-static struct dentry *export_iget(struct super_block *sb, unsigned long ino, __u32 generation)
+static struct dentry *get_dentry(struct super_block *sb, void *vobjp)
 {
-
-       /* iget isn't really right if the inode is currently unallocated!!
-        * This should really all be done inside each filesystem
-        *
-        * ext2fs' read_inode has been strengthed to return a bad_inode if
-        * the inode had been deleted.
-        *
-        * Currently we don't know the generation for parent directory, so
-        * a generation of 0 means "accept any"
-        */
-       struct inode *inode;
-       struct dentry *result;
-       if (ino == 0)
-               return ERR_PTR(-ESTALE);
-       inode = iget(sb, ino);
-       if (inode == NULL)
-               return ERR_PTR(-ENOMEM);
-       if (is_bad_inode(inode)
-           || (generation && inode->i_generation != generation)
-               ) {
-               /* we didn't find the right inode.. */
-               dprintk("fh_verify: Inode %lu, Bad count: %d %d or version  %u %u\n",
-                       inode->i_ino,
-                       inode->i_nlink, atomic_read(&inode->i_count),
-                       inode->i_generation,
-                       generation);
-
-               iput(inode);
-               return ERR_PTR(-ESTALE);
-       }
-       /* now to find a dentry.
-        * If possible, get a well-connected one
-        */
-       result = d_alloc_anon(inode);
-       if (!result) {
-               iput(inode);
-               return ERR_PTR(-ENOMEM);
-       }
-       return result;
+       return ERR_PTR(-ESTALE);
 }
 
-
-static struct dentry *get_object(struct super_block *sb, void *vobjp)
-{
-       __u32 *objp = vobjp;
-       unsigned long ino = objp[0];
-       __u32 generation = objp[1];
-
-       return export_iget(sb, ino, generation);
-}
-
-
 /**
  * export_encode_fh - default export_operations->encode_fh function
  * @dentry:  the dentry to encode
@@ -524,7 +474,7 @@ struct export_operations export_op_default = {
 
        .get_name       = get_name,
        .get_parent     = get_parent,
-       .get_dentry     = get_object,
+       .get_dentry     = get_dentry,
 };
 
 EXPORT_SYMBOL(export_op_default);

diff --git a/fs/jfs/jfs_inode.h b/fs/jfs/jfs_inode.h
index 2374b59..f0ec72b 100644 (file)
--- a/fs/jfs/jfs_inode.h
+++ b/fs/jfs/jfs_inode.h
@@ -32,6 +32,7 @@ extern void jfs_truncate_nolock(struct inode *, loff_t);
 extern void jfs_free_zero_link(struct inode *);
 extern struct dentry *jfs_get_parent(struct dentry *dentry);
 extern void jfs_get_inode_flags(struct jfs_inode_info *);
+extern struct dentry *jfs_get_dentry(struct super_block *sb, void *vobjp);
 extern void jfs_set_inode_flags(struct inode *);
 extern int jfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 25161c4..932797b 100644 (file)
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1477,6 +1477,38 @@ static struct dentry *jfs_lookup(struct inode *dip, struct dentry *dentry, struc
        return dentry;
 }
 
+struct dentry *jfs_get_dentry(struct super_block *sb, void *vobjp)
+{
+       __u32 *objp = vobjp;
+       unsigned long ino = objp[0];
+       __u32 generation = objp[1];
+       struct inode *inode;
+       struct dentry *result;
+
+       if (ino == 0)
+               return ERR_PTR(-ESTALE);
+       inode = iget(sb, ino);
+       if (inode == NULL)
+               return ERR_PTR(-ENOMEM);
+
+       if (is_bad_inode(inode) ||
+           (generation && inode->i_generation != generation)) {
+               result = ERR_PTR(-ESTALE);
+               goto out_iput;
+       }
+
+       result = d_alloc_anon(inode);
+       if (!result) {
+               result = ERR_PTR(-ENOMEM);
+               goto out_iput;
+       }
+       return result;
+
+ out_iput:
+       iput(inode);
+       return result;
+}
+
 struct dentry *jfs_get_parent(struct dentry *dentry)
 {
        struct super_block *sb = dentry->d_inode->i_sb;

diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 49b652b..929fcec 100644 (file)
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -738,6 +738,7 @@ static const struct super_operations jfs_super_operations = {
 };
 
 static struct export_operations jfs_export_operations = {
+       .get_dentry     = jfs_get_dentry,
        .get_parent     = jfs_get_parent,
 };
 

diff --git a/include/linux/efs_fs.h b/include/linux/efs_fs.h
index dfed800..16cb25c 100644 (file)
--- a/include/linux/efs_fs.h
+++ b/include/linux/efs_fs.h
@@ -45,6 +45,7 @@ extern efs_block_t efs_map_block(struct inode *, efs_block_t);
 extern int efs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 
 extern struct dentry *efs_lookup(struct inode *, struct dentry *, struct nameidata *);
+extern struct dentry *efs_get_dentry(struct super_block *sb, void *vobjp);
 extern struct dentry *efs_get_parent(struct dentry *);
 extern int efs_bmap(struct inode *, int);