This is a note to let you know that I've just added the patch titled nfsd: Extend the mutex holding region around in nfsd4_process_open2() to the 4.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfsd-extend-the-mutex-holding-region-around-in-nfsd4_process_open2.patch and it can be found in the queue-4.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 5cc1fb2a093e254b656c64ff24b0b76bed1d34d9 Mon Sep 17 00:00:00 2001 From: Oleg Drokin <green@xxxxxxxxxxxxxx> Date: Tue, 14 Jun 2016 23:28:05 -0400 Subject: nfsd: Extend the mutex holding region around in nfsd4_process_open2() From: Oleg Drokin <green@xxxxxxxxxxxxxx> commit 5cc1fb2a093e254b656c64ff24b0b76bed1d34d9 upstream. To avoid racing entry into nfs4_get_vfs_file(). Make init_open_stateid() return with locked stateid to be unlocked by the caller. Signed-off-by: Oleg Drokin <green@xxxxxxxxxxxxxx> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/nfsd/nfs4state.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3487,6 +3487,10 @@ init_open_stateid(struct nfs4_ol_stateid struct nfs4_openowner *oo = open->op_openowner; struct nfs4_ol_stateid *retstp = NULL; + /* We are moving these outside of the spinlocks to avoid the warnings */ + mutex_init(&stp->st_mutex); + mutex_lock(&stp->st_mutex); + spin_lock(&oo->oo_owner.so_client->cl_lock); spin_lock(&fp->fi_lock); @@ -3502,13 +3506,17 @@ init_open_stateid(struct nfs4_ol_stateid stp->st_access_bmap = 0; stp->st_deny_bmap = 0; stp->st_openstp = NULL; - mutex_init(&stp->st_mutex); list_add(&stp->st_perstateowner, &oo->oo_owner.so_stateids); list_add(&stp->st_perfile, &fp->fi_stateids); out_unlock: spin_unlock(&fp->fi_lock); spin_unlock(&oo->oo_owner.so_client->cl_lock); + if (retstp) { + mutex_lock(&retstp->st_mutex); + /* Not that we need to, just for neatness */ + mutex_unlock(&stp->st_mutex); + } return retstp; } @@ -4344,11 +4352,14 @@ nfsd4_process_open2(struct svc_rqst *rqs } else { stp = open->op_stp; open->op_stp = NULL; + /* + * init_open_stateid() either returns a locked stateid + * it found, or initializes and locks the new one we passed in + */ swapstp = init_open_stateid(stp, fp, open); if (swapstp) { nfs4_put_stid(&stp->st_stid); stp = swapstp; - mutex_lock(&stp->st_mutex); status = nfs4_upgrade_open(rqstp, fp, current_fh, stp, open); if (status) { @@ -4357,7 +4368,6 @@ nfsd4_process_open2(struct svc_rqst *rqs } goto upgrade_out; } - mutex_lock(&stp->st_mutex); status = nfs4_get_vfs_file(rqstp, fp, current_fh, stp, open); if (status) { mutex_unlock(&stp->st_mutex); Patches currently in stable-queue which might be from green@xxxxxxxxxxxxxx are queue-4.6/nfsd-always-lock-state-exclusively.patch queue-4.6/nfsd-extend-the-mutex-holding-region-around-in-nfsd4_process_open2.patch queue-4.6/make-nfs_atomic_open-call-d_drop-on-all-open_context-errors.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html