From: Trond Myklebust Date: Thu, 10 Jul 2014 18:07:26 +0000 (-0400) Subject: nfsd: Add locking to the nfs4_file->fi_fds[] array X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=de18643dce70e0d7c3dbccb5d2c8f17f04bc24a6;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git nfsd: Add locking to the nfs4_file->fi_fds[] array Preparation for removal of the client_mutex, which currently protects this array. While we don't actually need the find_*_file_locked variants just yet, a later patch will. So go ahead and add them now to reduce future churn in this code. Signed-off-by: Trond Myklebust Signed-off-by: Jeff Layton Reviewed-by: Christoph Hellwig Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index cfb10d060c83..314dc8061461 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -268,6 +268,79 @@ get_nfs4_file(struct nfs4_file *fi) atomic_inc(&fi->fi_ref); } +static struct file * +__nfs4_get_fd(struct nfs4_file *f, int oflag) +{ + if (f->fi_fds[oflag]) + return get_file(f->fi_fds[oflag]); + return NULL; +} + +static struct file * +find_writeable_file_locked(struct nfs4_file *f) +{ + struct file *ret; + + lockdep_assert_held(&f->fi_lock); + + ret = __nfs4_get_fd(f, O_WRONLY); + if (!ret) + ret = __nfs4_get_fd(f, O_RDWR); + return ret; +} + +static struct file * +find_writeable_file(struct nfs4_file *f) +{ + struct file *ret; + + spin_lock(&f->fi_lock); + ret = find_writeable_file_locked(f); + spin_unlock(&f->fi_lock); + + return ret; +} + +static struct file *find_readable_file_locked(struct nfs4_file *f) +{ + struct file *ret; + + lockdep_assert_held(&f->fi_lock); + + ret = __nfs4_get_fd(f, O_RDONLY); + if (!ret) + ret = __nfs4_get_fd(f, O_RDWR); + return ret; +} + +static struct file * +find_readable_file(struct nfs4_file *f) +{ + struct file *ret; + + spin_lock(&f->fi_lock); + ret = find_readable_file_locked(f); + spin_unlock(&f->fi_lock); + + return ret; +} + +static struct file * +find_any_file(struct nfs4_file *f) +{ + struct file *ret; + + spin_lock(&f->fi_lock); + ret = __nfs4_get_fd(f, O_RDWR); + if (!ret) { + ret = __nfs4_get_fd(f, O_WRONLY); + if (!ret) + ret = __nfs4_get_fd(f, O_RDONLY); + } + spin_unlock(&f->fi_lock); + return ret; +} + static int num_delegations; unsigned long max_delegations; @@ -316,20 +389,31 @@ static void nfs4_file_get_access(struct nfs4_file *fp, int oflag) __nfs4_file_get_access(fp, oflag); } -static void nfs4_file_put_fd(struct nfs4_file *fp, int oflag) +static struct file *nfs4_file_put_fd(struct nfs4_file *fp, int oflag) { - if (fp->fi_fds[oflag]) { - fput(fp->fi_fds[oflag]); - fp->fi_fds[oflag] = NULL; - } + struct file *filp; + + filp = fp->fi_fds[oflag]; + fp->fi_fds[oflag] = NULL; + return filp; } static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag) { - if (atomic_dec_and_test(&fp->fi_access[oflag])) { - nfs4_file_put_fd(fp, oflag); + might_lock(&fp->fi_lock); + + if (atomic_dec_and_lock(&fp->fi_access[oflag], &fp->fi_lock)) { + struct file *f1 = NULL; + struct file *f2 = NULL; + + f1 = nfs4_file_put_fd(fp, oflag); if (atomic_read(&fp->fi_access[1 - oflag]) == 0) - nfs4_file_put_fd(fp, O_RDWR); + f2 = nfs4_file_put_fd(fp, O_RDWR); + spin_unlock(&fp->fi_lock); + if (f1) + fput(f1); + if (f2) + fput(f2); } } @@ -737,8 +821,10 @@ static void __release_lock_stateid(struct nfs4_ol_stateid *stp) unhash_generic_stateid(stp); unhash_stid(&stp->st_stid); file = find_any_file(stp->st_file); - if (file) + if (file) { locks_remove_posix(file, (fl_owner_t)lockowner(stp->st_stateowner)); + fput(file); + } close_generic_stateid(stp); free_generic_stateid(stp); } @@ -3206,17 +3292,27 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh, static __be32 nfs4_get_vfs_file(struct svc_rqst *rqstp, struct nfs4_file *fp, struct svc_fh *cur_fh, struct nfsd4_open *open) { + struct file *filp = NULL; __be32 status; int oflag = nfs4_access_to_omode(open->op_share_access); int access = nfs4_access_to_access(open->op_share_access); + spin_lock(&fp->fi_lock); if (!fp->fi_fds[oflag]) { - status = nfsd_open(rqstp, cur_fh, S_IFREG, access, - &fp->fi_fds[oflag]); + spin_unlock(&fp->fi_lock); + status = nfsd_open(rqstp, cur_fh, S_IFREG, access, &filp); if (status) goto out; + spin_lock(&fp->fi_lock); + if (!fp->fi_fds[oflag]) { + fp->fi_fds[oflag] = filp; + filp = NULL; + } } nfs4_file_get_access(fp, oflag); + spin_unlock(&fp->fi_lock); + if (filp) + fput(filp); status = nfsd4_truncate(rqstp, cur_fh, open); if (status) @@ -3301,13 +3397,15 @@ static int nfs4_setlease(struct nfs4_delegation *dp) if (status) goto out_free; fp->fi_lease = fl; - fp->fi_deleg_file = get_file(fl->fl_file); + fp->fi_deleg_file = fl->fl_file; atomic_set(&fp->fi_delegees, 1); spin_lock(&state_lock); hash_delegation_locked(dp, fp); spin_unlock(&state_lock); return 0; out_free: + if (fl->fl_file) + fput(fl->fl_file); locks_free_lock(fl); return status; } @@ -3905,6 +4003,7 @@ nfs4_preprocess_stateid_op(struct net *net, struct nfsd4_compound_state *cstate, status = nfserr_serverfault; goto out; } + get_file(file); } break; case NFS4_OPEN_STID: @@ -3932,7 +4031,7 @@ nfs4_preprocess_stateid_op(struct net *net, struct nfsd4_compound_state *cstate, } status = nfs_ok; if (file) - *filpp = get_file(file); + *filpp = file; out: nfs4_unlock_state(); return status; @@ -4653,6 +4752,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, break; } out: + if (filp) + fput(filp); if (status && new_state) release_lock_stateid(lock_stp); nfsd4_bump_seqid(cstate, status); @@ -4793,7 +4894,7 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, if (!file_lock) { dprintk("NFSD: %s: unable to allocate lock!\n", __func__); status = nfserr_jukebox; - goto out; + goto fput; } locks_init_lock(file_lock); file_lock->fl_type = F_UNLCK; @@ -4815,7 +4916,8 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, } update_stateid(&stp->st_stid.sc_stateid); memcpy(&locku->lu_stateid, &stp->st_stid.sc_stateid, sizeof(stateid_t)); - +fput: + fput(filp); out: nfsd4_bump_seqid(cstate, status); if (!cstate->replay_owner) @@ -4826,7 +4928,7 @@ out: out_nfserr: status = nfserrno(err); - goto out; + goto fput; } /* diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index 04737b3ed363..9f1159d5de56 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -398,32 +398,6 @@ struct nfs4_file { bool fi_had_conflict; }; -/* XXX: for first cut may fall back on returning file that doesn't work - * at all? */ -static inline struct file *find_writeable_file(struct nfs4_file *f) -{ - if (f->fi_fds[O_WRONLY]) - return f->fi_fds[O_WRONLY]; - return f->fi_fds[O_RDWR]; -} - -static inline struct file *find_readable_file(struct nfs4_file *f) -{ - if (f->fi_fds[O_RDONLY]) - return f->fi_fds[O_RDONLY]; - return f->fi_fds[O_RDWR]; -} - -static inline struct file *find_any_file(struct nfs4_file *f) -{ - if (f->fi_fds[O_RDWR]) - return f->fi_fds[O_RDWR]; - else if (f->fi_fds[O_WRONLY]) - return f->fi_fds[O_WRONLY]; - else - return f->fi_fds[O_RDONLY]; -} - /* "ol" stands for "Open or Lock". Better suggestions welcome. */ struct nfs4_ol_stateid { struct nfs4_stid st_stid; /* must be first field */