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Commit 55ef1274 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd: Ensure nfsv4 calls the underlying filesystem on LOCKT 



Since nfsv4 allows LOCKT without an open, but the ->lock() method is a
file method, we fake up a struct file in the nfsv4 code with just the
fields we need initialized.  But we forgot to initialize the file
operations, with the result that LOCKT never results in a call to the
filesystem's ->lock() method (if it exists).

We could just add that one more initialization.  But this hack of faking
up a struct file with only some fields initialized seems the kind of
thing that might cause more problems in the future.  We should either do
an open and get a real struct file, or make lock-testing an inode (not a
file) method.

This patch does the former.

Reported-by: default avatarMarc Eshel <eshel@almaden.ibm.com>
Tested-by: default avatarMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent 69b6ba37

fs/nfsd/nfs4state.c

+20 −10
Original line number Diff line number Diff line
@@ -2781,6 +2781,25 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, 
	return status;

}



/*

 * The NFSv4 spec allows a client to do a LOCKT without holding an OPEN,

 * so we do a temporary open here just to get an open file to pass to

 * vfs_test_lock.  (Arguably perhaps test_lock should be done with an

 * inode operation.)

 */

static int nfsd_test_lock(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file_lock *lock)

{

	struct file *file;

	int err;



	err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file);

	if (err)

		return err;

	err = vfs_test_lock(file, lock);

	nfsd_close(file);

	return err;

}



/*

 * LOCKT operation

 */
@@ -2789,7 +2808,6 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, 
	    struct nfsd4_lockt *lockt)

{

	struct inode *inode;

	struct file file;

	struct file_lock file_lock;

	int error;

	__be32 status;
@@ -2847,16 +2865,8 @@ nfsd4_lockt(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, 


	nfs4_transform_lock_offset(&file_lock);



	/* vfs_test_lock uses the struct file _only_ to resolve the inode.

	 * since LOCKT doesn't require an OPEN, and therefore a struct

	 * file may not exist, pass vfs_test_lock a struct file with

	 * only the dentry:inode set.

	 */

	memset(&file, 0, sizeof (struct file));

	file.f_path.dentry = cstate->current_fh.fh_dentry;



	status = nfs_ok;

	error = vfs_test_lock(&file, &file_lock);

	error = nfsd_test_lock(rqstp, &cstate->current_fh, &file_lock);

	if (error) {

		status = nfserrno(error);

		goto out;