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knfsd: exportfs: remove iget abuse

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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>
This commit is contained in:
Christoph Hellwig
2007-07-17 04:04:29 -07:00
committed by Linus Torvalds
parent a569425512
commit 5ca2960733
7 changed files with 71 additions and 53 deletions
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56
fs/exportfs/expfs.c
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@@ -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);