From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: [PATCH 6/8] afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus() From: David Howells To: viro@zeniv.linux.org.uk Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Wed, 23 May 2018 13:17:19 +0100 Message-ID: <152707783954.27887.13200491028680328553.stgit@warthog.procyon.org.uk> In-Reply-To: <152707780120.27887.10118775145086304138.stgit@warthog.procyon.org.uk> References: <152707780120.27887.10118775145086304138.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 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: David Howells --- fs/afs/fsclient.c | 97 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 55 insertions(+), 42 deletions(-) diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c index efacdb7c1dee..b695d9e16c65 100644 --- a/fs/afs/fsclient.c +++ b/fs/afs/fsclient.c @@ -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; } /* @@ -374,8 +387,8 @@ 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, - &call->expected_version, NULL) < 0) + 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); if (call->reply[1]) @@ -555,8 +568,8 @@ 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, - &vnode->status.data_version, req) < 0) + 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); if (call->reply[1]) @@ -708,9 +721,9 @@ 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, - &call->expected_version, NULL) < 0) + 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]); /* xdr_decode_AFSVolSync(&bp, call->reply[X]); */ @@ -814,8 +827,8 @@ 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, - &call->expected_version, NULL) < 0) + 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]); */ @@ -904,9 +917,9 @@ 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, - &call->expected_version, NULL) < 0) + 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]); */ @@ -991,9 +1004,9 @@ 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, - &call->expected_version, NULL) < 0) + 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]); */ @@ -1097,12 +1110,12 @@ 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, - &call->expected_version, NULL) < 0) + 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, - &call->expected_version_2, NULL) < 0) + 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]); */ @@ -1206,8 +1219,8 @@ 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, - &call->expected_version, NULL) < 0) + 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]); */ @@ -1382,8 +1395,8 @@ 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, - &call->expected_version, NULL) < 0) + 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]); */ @@ -2084,8 +2097,8 @@ 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, - &call->expected_version, NULL); + 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]); callback[call->count].type = ntohl(bp[2]); @@ -2196,9 +2209,9 @@ 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], - call->count == 0 ? vnode : NULL, - NULL, NULL) < 0) + if (afs_decode_status(call, &bp, &statuses[call->count], + call->count == 0 ? vnode : NULL, + NULL, NULL) < 0) return afs_protocol_error(call, -EBADMSG); call->count++;