Patch "NFSD: Add an nfsd_file_fsync tracepoint" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    NFSD: Add an nfsd_file_fsync tracepoint

to the 5.10-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-add-an-nfsd_file_fsync-tracepoint.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3a84f24ebc03067c3e24dcc9d48b1ca5fb5659be
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date:   Thu Nov 3 16:22:48 2022 -0400

    NFSD: Add an nfsd_file_fsync tracepoint
    
    [ Upstream commit d7064eaf688cfe454c50db9f59298463d80d403c ]
    
    Add a tracepoint to capture the number of filecache-triggered fsync
    calls and which files needed it. Also, record when an fsync triggers
    a write verifier reset.
    
    Examples:
    
    <...>-97    [007]   262.505611: nfsd_file_free:       inode=0xffff888171e08140 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d2400
    <...>-97    [007]   262.505612: nfsd_file_fsync:      inode=0xffff888171e08140 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d2400 ret=0
    <...>-97    [007]   262.505623: nfsd_file_free:       inode=0xffff888171e08dc0 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d1e00
    <...>-97    [007]   262.505624: nfsd_file_fsync:      inode=0xffff888171e08dc0 ref=0 flags=GC may=WRITE nf_file=0xffff8881373d1e00 ret=0
    
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 522e900a88605..6b8873b0c2c38 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -335,10 +335,13 @@ static void
 nfsd_file_fsync(struct nfsd_file *nf)
 {
 	struct file *file = nf->nf_file;
+	int ret;
 
 	if (!file || !(file->f_mode & FMODE_WRITE))
 		return;
-	if (vfs_fsync(file, 1) != 0)
+	ret = vfs_fsync(file, 1);
+	trace_nfsd_file_fsync(nf, ret);
+	if (ret)
 		nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id));
 }
 
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 5faec08ac7cf7..235ea38da8644 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -1151,6 +1151,37 @@ DEFINE_EVENT(nfsd_file_lruwalk_class, name,				\
 DEFINE_NFSD_FILE_LRUWALK_EVENT(nfsd_file_gc_removed);
 DEFINE_NFSD_FILE_LRUWALK_EVENT(nfsd_file_shrinker_removed);
 
+TRACE_EVENT(nfsd_file_fsync,
+	TP_PROTO(
+		const struct nfsd_file *nf,
+		int ret
+	),
+	TP_ARGS(nf, ret),
+	TP_STRUCT__entry(
+		__field(void *, nf_inode)
+		__field(int, nf_ref)
+		__field(int, ret)
+		__field(unsigned long, nf_flags)
+		__field(unsigned char, nf_may)
+		__field(struct file *, nf_file)
+	),
+	TP_fast_assign(
+		__entry->nf_inode = nf->nf_inode;
+		__entry->nf_ref = refcount_read(&nf->nf_ref);
+		__entry->ret = ret;
+		__entry->nf_flags = nf->nf_flags;
+		__entry->nf_may = nf->nf_may;
+		__entry->nf_file = nf->nf_file;
+	),
+	TP_printk("inode=%p ref=%d flags=%s may=%s nf_file=%p ret=%d",
+		__entry->nf_inode,
+		__entry->nf_ref,
+		show_nf_flags(__entry->nf_flags),
+		show_nfsd_may_flags(__entry->nf_may),
+		__entry->nf_file, __entry->ret
+	)
+);
+
 #include "cache.h"
 
 TRACE_DEFINE_ENUM(RC_DROPIT);