5.10-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit c035362eb935fe9381d9d1cc453bc2a37460e24c ]
Subsequent patches will use this mechanism to wake up an operation that is waiting for a client to return a delegation.
The new tracepoint records whether the wait timed out or was properly awoken by the expected DELEGRETURN:
nfsd-1155 [002] 83799.493199: nfsd_delegret_wakeup: xid=0x14b7d6ef fh_hash=0xf6826792 (timed out)
Suggested-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4state.c | 30 ++++++++++++++++++++++++++++++ fs/nfsd/nfsd.h | 7 +++++++ fs/nfsd/trace.h | 23 +++++++++++++++++++++++ 3 files changed, 60 insertions(+)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 8bbff388e4f03..2bb78ab4f6c31 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4734,6 +4734,35 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type) return ret; }
+static bool nfsd4_deleg_present(const struct inode *inode) +{ + struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx); + + return ctx && !list_empty_careful(&ctx->flc_lease); +} + +/** + * nfsd_wait_for_delegreturn - wait for delegations to be returned + * @rqstp: the RPC transaction being executed + * @inode: in-core inode of the file being waited for + * + * The timeout prevents deadlock if all nfsd threads happen to be + * tied up waiting for returning delegations. + * + * Return values: + * %true: delegation was returned + * %false: timed out waiting for delegreturn + */ +bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode) +{ + long __maybe_unused timeo; + + timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode), + NFSD_DELEGRETURN_TIMEOUT); + trace_nfsd_delegret_wakeup(rqstp, inode, timeo); + return timeo > 0; +} + static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb) { struct nfs4_delegation *dp = cb_to_delegation(cb); @@ -6811,6 +6840,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, if (status) goto put_stateid;
+ wake_up_var(d_inode(cstate->current_fh.fh_dentry)); destroy_delegation(dp); put_stateid: nfs4_put_stid(&dp->dl_stid); diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h index 57a468ed85c35..6ab4ad41ae84e 100644 --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -164,6 +164,7 @@ char * nfs4_recoverydir(void); bool nfsd4_spo_must_allow(struct svc_rqst *rqstp); int nfsd4_create_laundry_wq(void); void nfsd4_destroy_laundry_wq(void); +bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, struct inode *inode); #else static inline int nfsd4_init_slabs(void) { return 0; } static inline void nfsd4_free_slabs(void) { } @@ -179,6 +180,11 @@ static inline bool nfsd4_spo_must_allow(struct svc_rqst *rqstp) } static inline int nfsd4_create_laundry_wq(void) { return 0; }; static inline void nfsd4_destroy_laundry_wq(void) {}; +static inline bool nfsd_wait_for_delegreturn(struct svc_rqst *rqstp, + struct inode *inode) +{ + return false; +} #endif
/* @@ -343,6 +349,7 @@ void nfsd_lockd_shutdown(void); #define NFSD_COURTESY_CLIENT_TIMEOUT (24 * 60 * 60) /* seconds */ #define NFSD_CLIENT_MAX_TRIM_PER_RUN 128 #define NFS4_CLIENTS_PER_GB 1024 +#define NFSD_DELEGRETURN_TIMEOUT (HZ / 34) /* 30ms */
/* * The following attributes are currently not supported by the NFSv4 server: diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 0ee4220a289a0..6803ac877ff70 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -454,6 +454,29 @@ DEFINE_NFSD_COPY_ERR_EVENT(clone_file_range_err); #include "filecache.h" #include "vfs.h"
+TRACE_EVENT(nfsd_delegret_wakeup, + TP_PROTO( + const struct svc_rqst *rqstp, + const struct inode *inode, + long timeo + ), + TP_ARGS(rqstp, inode, timeo), + TP_STRUCT__entry( + __field(u32, xid) + __field(const void *, inode) + __field(long, timeo) + ), + TP_fast_assign( + __entry->xid = be32_to_cpu(rqstp->rq_xid); + __entry->inode = inode; + __entry->timeo = timeo; + ), + TP_printk("xid=0x%08x inode=%p%s", + __entry->xid, __entry->inode, + __entry->timeo == 0 ? " (timed out)" : "" + ) +); + DECLARE_EVENT_CLASS(nfsd_stateid_class, TP_PROTO(stateid_t *stp), TP_ARGS(stp),