Commit 5ca29607 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

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: default avatarDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a5694255

fs/efs/namei.c

+32 −0
Original line number Diff line number Diff line
@@ -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;

fs/efs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

};

fs/exportfs/expfs.c

+3 −53
Original line number Diff line number Diff line
@@ -391,60 +391,10 @@ 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;

}





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
@@ -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);

fs/jfs/jfs_inode.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

fs/jfs/namei.c

+32 −0
Original line number Diff line number Diff line
@@ -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;

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