queue-5.15/nfsd-add-an-nfsd_file_fsync-tracepoint.patch

   1 From c0629d6013d038d0c6d484c0c5905274a4fe775f Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Thu, 3 Nov 2022 16:22:48 -0400
   4 Subject: NFSD: Add an nfsd_file_fsync tracepoint
   5
   6 From: Chuck Lever <chuck.lever@oracle.com>
   7
   8 [ Upstream commit d7064eaf688cfe454c50db9f59298463d80d403c ]
   9
  10 Add a tracepoint to capture the number of filecache-triggered fsync
  11 calls and which files needed it. Also, record when an fsync triggers
  12 a write verifier reset.
  13
  14 Examples:
  15
  16 <...>-97    [007]   262.505611: nfsd_file_free:       inode=0xffff888171e08140 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d2400
  17 <...>-97    [007]   262.505612: nfsd_file_fsync:      inode=0xffff888171e08140 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d2400 ret=0
  18 <...>-97    [007]   262.505623: nfsd_file_free:       inode=0xffff888171e08dc0 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d1e00
  19 <...>-97    [007]   262.505624: nfsd_file_fsync:      inode=0xffff888171e08dc0 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d1e00 ret=0
  20
  21 Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
  22 Reviewed-by: Jeff Layton <jlayton@kernel.org>
  23 Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
  24 ---
  25  fs/nfsd/filecache.c |  5 ++++-
  26  fs/nfsd/trace.h     | 31 +++++++++++++++++++++++++++++++
  27  2 files changed, 35 insertions(+), 1 deletion(-)
  28
  29 diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
  30 index 522e900a88605..6b8873b0c2c38 100644
  31 --- a/fs/nfsd/filecache.c
  32 +++ b/fs/nfsd/filecache.c
  33 @@ -335,10 +335,13 @@ static void
  34  nfsd_file_fsync(struct nfsd_file *nf)
  35  {
  36         struct file *file = nf->nf_file;
  37 +       int ret;
  38
  39         if (!file || !(file->f_mode & FMODE_WRITE))
  40                 return;
  41 -       if (vfs_fsync(file, 1) != 0)
  42 +       ret = vfs_fsync(file, 1);
  43 +       trace_nfsd_file_fsync(nf, ret);
  44 +       if (ret)
  45                 nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
  46  }
  47
  48 diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
  49 index 2c72a666aa9c2..eb155e98a9dc2 100644
  50 --- a/fs/nfsd/trace.h
  51 +++ b/fs/nfsd/trace.h
  52 @@ -1237,6 +1237,37 @@ DEFINE_EVENT(nfsd_file_lruwalk_class, name,                              \
  53  DEFINE_NFSD_FILE_LRUWALK_EVENT(nfsd_file_gc_removed);
  54  DEFINE_NFSD_FILE_LRUWALK_EVENT(nfsd_file_shrinker_removed);
  55
  56 +TRACE_EVENT(nfsd_file_fsync,
  57 +       TP_PROTO(
  58 +               const struct nfsd_file *nf,
  59 +               int ret
  60 +       ),
  61 +       TP_ARGS(nf, ret),
  62 +       TP_STRUCT__entry(
  63 +               __field(void *, nf_inode)
  64 +               __field(int, nf_ref)
  65 +               __field(int, ret)
  66 +               __field(unsigned long, nf_flags)
  67 +               __field(unsigned char, nf_may)
  68 +               __field(struct file *, nf_file)
  69 +       ),
  70 +       TP_fast_assign(
  71 +               __entry->nf_inode = nf->nf_inode;
  72 +               __entry->nf_ref = refcount_read(&nf->nf_ref);
  73 +               __entry->ret = ret;
  74 +               __entry->nf_flags = nf->nf_flags;
  75 +               __entry->nf_may = nf->nf_may;
  76 +               __entry->nf_file = nf->nf_file;
  77 +       ),
  78 +       TP_printk("inode=%p ref=%d flags=%s may=%s nf_file=%p ret=%d",
  79 +               __entry->nf_inode,
  80 +               __entry->nf_ref,
  81 +               show_nf_flags(__entry->nf_flags),
  82 +               show_nfsd_may_flags(__entry->nf_may),
  83 +               __entry->nf_file, __entry->ret
  84 +       )
  85 +);
  86 +
  87  #include "cache.h"
  88
  89  TRACE_DEFINE_ENUM(RC_DROPIT);
  90 --
  91 2.43.0
  92