Add a tracepoint to log internal failures (such as cache errors) that we don't otherwise want to pass back to the netfs. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Tested-by: Jeff Layton <jlayton@xxxxxxxxxx> Tested-by: Dave Wysochanski <dwysocha@xxxxxxxxxx> Tested-By: Marc Dionne <marc.dionne@xxxxxxxxxxxx> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> cc: linux-mm@xxxxxxxxx cc: linux-cachefs@xxxxxxxxxx cc: linux-afs@xxxxxxxxxxxxxxxxxxx cc: linux-nfs@xxxxxxxxxxxxxxx cc: linux-cifs@xxxxxxxxxxxxxxx cc: ceph-devel@xxxxxxxxxxxxxxx cc: v9fs-developer@xxxxxxxxxxxxxxxxxxxxx cc: linux-fsdevel@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/161781048813.463527.1557000804674707986.stgit@xxxxxxxxxxxxxxxxxxxxxx/ Link: https://lore.kernel.org/r/161789082749.6155.15498680577213140870.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v6 --- fs/netfs/read_helper.c | 14 +++++++++- include/trace/events/netfs.h | 58 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 70 insertions(+), 2 deletions(-) diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index cd3b61d5e192..1d3b50c5db6d 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -271,6 +271,8 @@ static void netfs_rreq_copy_terminated(void *priv, ssize_t transferred_or_error, if (IS_ERR_VALUE(transferred_or_error)) { netfs_stat(&netfs_n_rh_write_failed); + trace_netfs_failure(rreq, subreq, transferred_or_error, + netfs_fail_copy_to_cache); } else { netfs_stat(&netfs_n_rh_write_done); } @@ -323,6 +325,7 @@ static void netfs_rreq_do_write_to_cache(struct netfs_read_request *rreq) ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len, rreq->i_size); if (ret < 0) { + trace_netfs_failure(rreq, subreq, ret, netfs_fail_prepare_write); trace_netfs_sreq(subreq, netfs_sreq_trace_write_skip); continue; } @@ -627,6 +630,8 @@ void netfs_subreq_terminated(struct netfs_read_subrequest *subreq, if (IS_ERR_VALUE(transferred_or_error)) { subreq->error = transferred_or_error; + trace_netfs_failure(rreq, subreq, transferred_or_error, + netfs_fail_read); goto failed; } @@ -996,8 +1001,10 @@ int netfs_readpage(struct file *file, } while (test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags)); ret = rreq->error; - if (ret == 0 && rreq->submitted < rreq->len) + if (ret == 0 && rreq->submitted < rreq->len) { + trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_readpage); ret = -EIO; + } out: netfs_put_read_request(rreq, false); return ret; @@ -1069,6 +1076,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, /* Allow the netfs (eg. ceph) to flush conflicts. */ ret = ops->check_write_begin(file, pos, len, page, _fsdata); if (ret < 0) { + trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin); if (ret == -EAGAIN) goto retry; goto error; @@ -1145,8 +1153,10 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, } ret = rreq->error; - if (ret == 0 && rreq->submitted < rreq->len) + if (ret == 0 && rreq->submitted < rreq->len) { + trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_write_begin); ret = -EIO; + } netfs_put_read_request(rreq, false); if (ret < 0) goto error; diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index e3ebeabd3852..de1c64635e42 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -47,6 +47,15 @@ enum netfs_sreq_trace { netfs_sreq_trace_write_term, }; +enum netfs_failure { + netfs_fail_check_write_begin, + netfs_fail_copy_to_cache, + netfs_fail_read, + netfs_fail_short_readpage, + netfs_fail_short_write_begin, + netfs_fail_prepare_write, +}; + #endif #define netfs_read_traces \ @@ -81,6 +90,14 @@ enum netfs_sreq_trace { EM(netfs_sreq_trace_write_skip, "SKIP ") \ E_(netfs_sreq_trace_write_term, "WTERM") +#define netfs_failures \ + EM(netfs_fail_check_write_begin, "check-write-begin") \ + EM(netfs_fail_copy_to_cache, "copy-to-cache") \ + EM(netfs_fail_read, "read") \ + EM(netfs_fail_short_readpage, "short-readpage") \ + EM(netfs_fail_short_write_begin, "short-write-begin") \ + E_(netfs_fail_prepare_write, "prep-write") + /* * Export enum symbols via userspace. @@ -94,6 +111,7 @@ netfs_read_traces; netfs_rreq_traces; netfs_sreq_sources; netfs_sreq_traces; +netfs_failures; /* * Now redefine the EM() and E_() macros to map the enums to the strings that @@ -197,6 +215,46 @@ TRACE_EVENT(netfs_sreq, __entry->error) ); +TRACE_EVENT(netfs_failure, + TP_PROTO(struct netfs_read_request *rreq, + struct netfs_read_subrequest *sreq, + int error, enum netfs_failure what), + + TP_ARGS(rreq, sreq, error, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(unsigned short, index ) + __field(short, error ) + __field(unsigned short, flags ) + __field(enum netfs_read_source, source ) + __field(enum netfs_failure, what ) + __field(size_t, len ) + __field(size_t, transferred ) + __field(loff_t, start ) + ), + + TP_fast_assign( + __entry->rreq = rreq->debug_id; + __entry->index = sreq ? sreq->debug_index : 0; + __entry->error = error; + __entry->flags = sreq ? sreq->flags : 0; + __entry->source = sreq ? sreq->source : NETFS_INVALID_READ; + __entry->what = what; + __entry->len = sreq ? sreq->len : 0; + __entry->transferred = sreq ? sreq->transferred : 0; + __entry->start = sreq ? sreq->start : 0; + ), + + TP_printk("R=%08x[%u] %s f=%02x s=%llx %zx/%zx %s e=%d", + __entry->rreq, __entry->index, + __print_symbolic(__entry->source, netfs_sreq_sources), + __entry->flags, + __entry->start, __entry->transferred, __entry->len, + __print_symbolic(__entry->what, netfs_failures), + __entry->error) + ); + #endif /* _TRACE_NETFS_H */ /* This part must be outside protection */
