4.4-stable review patch. If anyone has any objections, please let me know.
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From: Trond Myklebust trond.myklebust@primarydata.com
commit d8a1a000555ecd1b824ac1ed6df8fe364dfbbbb0 upstream.
If nfsd4_process_open2() is initialising a new stateid, and yet the call to nfs4_get_vfs_file() fails for some reason, then we must declare the stateid closed, and unhash it before dropping the mutex.
Right now, we unhash the stateid after dropping the mutex, and without changing the stateid type, meaning that another OPEN could theoretically look it up and attempt to use it.
Reported-by: Andrew W Elble aweits@rit.edu Signed-off-by: Trond Myklebust trond.myklebust@primarydata.com Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/nfsd/nfs4state.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-)
--- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4319,6 +4319,7 @@ nfsd4_process_open2(struct svc_rqst *rqs struct nfs4_ol_stateid *stp = NULL; struct nfs4_delegation *dp = NULL; __be32 status; + bool new_stp = false;
/* * Lookup file; if found, lookup stateid and check open request, @@ -4338,11 +4339,19 @@ nfsd4_process_open2(struct svc_rqst *rqs goto out; }
+ if (!stp) { + stp = init_open_stateid(fp, open); + if (!open->op_stp) + new_stp = true; + } + /* * OPEN the file, or upgrade an existing OPEN. * If truncate fails, the OPEN fails. + * + * stp is already locked. */ - if (stp) { + if (!new_stp) { /* Stateid was found, this is an OPEN upgrade */ status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open); if (status) { @@ -4350,22 +4359,11 @@ nfsd4_process_open2(struct svc_rqst *rqs goto out; } } else { - /* stp is returned locked. */ - stp = init_open_stateid(fp, open); - /* See if we lost the race to some other thread */ - if (stp->st_access_bmap != 0) { - status = nfs4_upgrade_open(rqstp, fp, current_fh, - stp, open); - if (status) { - mutex_unlock(&stp->st_mutex); - goto out; - } - goto upgrade_out; - } status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open); if (status) { - mutex_unlock(&stp->st_mutex); + stp->st_stid.sc_type = NFS4_CLOSED_STID; release_open_stateid(stp); + mutex_unlock(&stp->st_mutex); goto out; }
@@ -4374,7 +4372,7 @@ nfsd4_process_open2(struct svc_rqst *rqs if (stp->st_clnt_odstate == open->op_odstate) open->op_odstate = NULL; } -upgrade_out: + nfs4_inc_and_copy_stateid(&open->op_stateid, &stp->st_stid); mutex_unlock(&stp->st_mutex);