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Commit c875c76a authored by David Howells's avatar David Howells
Browse files

afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus() 



Sparse doesn't appear able to handle the conditionally-taken locks in
xdr_decode_AFSFetchStatus(), even though the lock and unlock are both
contingent on the same unvarying function argument.

Deal with this by interpolating a wrapper function that takes the lock if
needed and calls xdr_decode_AFSFetchStatus() on two separate branches, one
with the lock held and one without.

This allows Sparse to work out the locking.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 564def71

fs/afs/fsclient.c

+55 −42
Original line number Diff line number Diff line
@@ -137,10 +137,6 @@ static int xdr_decode_AFSFetchStatus(struct afs_call *call, 
	u64 data_version, size;

	u32 type, abort_code;

	u8 flags = 0;

	int ret;



	if (vnode)

		write_seqlock(&vnode->cb_lock);



	if (xdr->if_version != htonl(AFS_FSTATUS_VERSION)) {

		pr_warn("Unknown AFSFetchStatus version %u\n", ntohl(xdr->if_version));
@@ -168,8 +164,7 @@ static int xdr_decode_AFSFetchStatus(struct afs_call *call, 
	case AFS_FTYPE_INVALID:

		if (abort_code != 0) {

			status->abort_code = abort_code;

			ret = 0;

			goto out;

			return 0;

		}

		/* Fall through */

	default:
@@ -222,17 +217,35 @@ static int xdr_decode_AFSFetchStatus(struct afs_call *call, 
					     flags);

	}



	ret = 0;



out:

	if (vnode)

		write_sequnlock(&vnode->cb_lock);

	return ret;

	return 0;



bad:

	xdr_dump_bad(*_bp);

	ret = afs_protocol_error(call, -EBADMSG);

	goto out;

	return afs_protocol_error(call, -EBADMSG);

}



/*

 * Decode the file status.  We need to lock the target vnode if we're going to

 * update its status so that stat() sees the attributes update atomically.

 */

static int afs_decode_status(struct afs_call *call,

			     const __be32 **_bp,

			     struct afs_file_status *status,

			     struct afs_vnode *vnode,

			     const afs_dataversion_t *expected_version,

			     struct afs_read *read_req)

{

	int ret;



	if (!vnode)

		return xdr_decode_AFSFetchStatus(call, _bp, status, vnode,

						 expected_version, read_req);



	write_seqlock(&vnode->cb_lock);

	ret = xdr_decode_AFSFetchStatus(call, _bp, status, vnode,

					expected_version, read_req);

	write_sequnlock(&vnode->cb_lock);

	return ret;

}



/*
@@ -374,7 +387,7 @@ static int afs_deliver_fs_fetch_status_vnode(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	xdr_decode_AFSCallBack(call, vnode, &bp);
@@ -555,7 +568,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call) 
			return ret;



		bp = call->buffer;

		if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

		if (afs_decode_status(call, &bp, &vnode->status, vnode,

				      &vnode->status.data_version, req) < 0)

			return afs_protocol_error(call, -EBADMSG);

		xdr_decode_AFSCallBack(call, vnode, &bp);
@@ -708,8 +721,8 @@ static int afs_deliver_fs_create_vnode(struct afs_call *call) 
	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	xdr_decode_AFSFid(&bp, call->reply[1]);

	if (xdr_decode_AFSFetchStatus(call, &bp, call->reply[2], NULL, NULL, NULL) < 0 ||

	    xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, call->reply[2], NULL, NULL, NULL) < 0 ||

	    afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	xdr_decode_AFSCallBack_raw(&bp, call->reply[3]);
@@ -814,7 +827,7 @@ static int afs_deliver_fs_remove(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -904,8 +917,8 @@ static int afs_deliver_fs_link(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode, NULL, NULL) < 0 ||

	    xdr_decode_AFSFetchStatus(call, &bp, &dvnode->status, dvnode,

	if (afs_decode_status(call, &bp, &vnode->status, vnode, NULL, NULL) < 0 ||

	    afs_decode_status(call, &bp, &dvnode->status, dvnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -991,8 +1004,8 @@ static int afs_deliver_fs_symlink(struct afs_call *call) 
	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	xdr_decode_AFSFid(&bp, call->reply[1]);

	if (xdr_decode_AFSFetchStatus(call, &bp, call->reply[2], NULL, NULL, NULL) ||

	    xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, call->reply[2], NULL, NULL, NULL) ||

	    afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -1097,11 +1110,11 @@ static int afs_deliver_fs_rename(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &orig_dvnode->status, orig_dvnode,

	if (afs_decode_status(call, &bp, &orig_dvnode->status, orig_dvnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	if (new_dvnode != orig_dvnode &&

	    xdr_decode_AFSFetchStatus(call, &bp, &new_dvnode->status, new_dvnode,

	    afs_decode_status(call, &bp, &new_dvnode->status, new_dvnode,

			      &call->expected_version_2, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -1206,7 +1219,7 @@ static int afs_deliver_fs_store_data(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -1382,7 +1395,7 @@ static int afs_deliver_fs_store_status(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	if (xdr_decode_AFSFetchStatus(call, &bp, &vnode->status, vnode,

	if (afs_decode_status(call, &bp, &vnode->status, vnode,

			      &call->expected_version, NULL) < 0)

		return afs_protocol_error(call, -EBADMSG);

	/* xdr_decode_AFSVolSync(&bp, call->reply[X]); */
@@ -2084,7 +2097,7 @@ static int afs_deliver_fs_fetch_status(struct afs_call *call) 


	/* unmarshall the reply once we've received all of it */

	bp = call->buffer;

	xdr_decode_AFSFetchStatus(call, &bp, status, vnode,

	afs_decode_status(call, &bp, status, vnode,

			  &call->expected_version, NULL);

	callback[call->count].version	= ntohl(bp[0]);

	callback[call->count].expiry	= ntohl(bp[1]);
@@ -2196,7 +2209,7 @@ static int afs_deliver_fs_inline_bulk_status(struct afs_call *call) 


		bp = call->buffer;

		statuses = call->reply[1];

		if (xdr_decode_AFSFetchStatus(call, &bp, &statuses[call->count],

		if (afs_decode_status(call, &bp, &statuses[call->count],

				      call->count == 0 ? vnode : NULL,

				      NULL, NULL) < 0)

			return afs_protocol_error(call, -EBADMSG);