[Linux-cachefs] [RFC PATCH 7/7] cifs: Use netfslib to handle reads
Rohith Surabattula
rohiths.msft at gmail.com
Mon Feb 28 14:14:35 UTC 2022
Hi David,
Below is the trace o/p when mounted with fsc option:
vi-1631 [000] ..... 2519.247539: netfs_read:
R=00000006 READAHEAD c=00000000 ni=0 s=0 1000
vi-1631 [000] ..... 2519.247540: netfs_read:
R=00000006 EXPANDED c=00000000 ni=0 s=0 1000
vi-1631 [000] ..... 2519.247550: netfs_sreq:
R=00000006[0] PREP DOWN f=00 s=0 0/100000 e=0
vi-1631 [000] ..... 2519.247551: netfs_sreq:
R=00000006[0] SUBMT DOWN f=00 s=0 0/100000 e=0
cifsd-1390 [001] ..... 2519.287542: netfs_sreq:
R=00000006[0] TERM DOWN f=02 s=0 100000/100000 e=0
cifsd-1390 [001] ..... 2519.287545: netfs_rreq:
R=00000006 ASSESS f=20
cifsd-1390 [001] ..... 2519.287545: netfs_rreq:
R=00000006 UNLOCK f=20
cifsd-1390 [001] ..... 2519.287571: netfs_rreq:
R=00000006 DONE f=00
cifsd-1390 [001] ..... 2519.287572: netfs_sreq:
R=00000006[0] FREE DOWN f=02 s=0 100000/100000 e=0
cifsd-1390 [001] ..... 2519.287573: netfs_rreq:
R=00000006 FREE f=00
Mount :
root at netfsvm:/sys/kernel/debug/tracing# sudo mount -t cifs
//netfsstg.file.core.windows.net/testshare on /mnt/testshare type cifs
(rw,relatime,vers=3.0,cache=strict,username=netfsstg,uid=0,noforceuid,gid=0,noforcegid,addr=52.239.170.72,file_mode=0777,dir_mode=0777,soft,persistenthandles,nounix,serverino,mapposix,fsc,rsize=1048576,wsize=1048576,bsize=1048576,echo_interval=60,actimeo=1)
I dont see writing fscache. It always downloads from the server.
root at netfsvm:/sys/kernel/debug/tracing# ps -A | grep cache
450 ? 00:00:00 mkey_cache
1361 ? 00:00:00 cachefilesd
root at netfsvm:/sys/kernel/debug/tracing# cat /proc/fs/fscache/stats
FS-Cache statistics
Cookies: n=29 v=1 vcol=0 voom=0
Acquire: n=29 ok=29 oom=0
LRU : n=0 exp=0 rmv=0 drp=0 at=0
Invals : n=0
Updates: n=0 rsz=0 rsn=0
Relinqs: n=0 rtr=0 drop=0
NoSpace: nwr=0 ncr=0 cull=0
IO : rd=0 wr=0
RdHelp : DR=0 RA=6 RP=0 WB=0 WBZ=7 rr=0 sr=0
RdHelp : ZR=0 sh=0 sk=7
RdHelp : DL=6 ds=6 df=0 di=0
RdHelp : RD=0 rs=0 rf=0
RdHelp : WR=0 ws=0 wf=0
root at netfsvm:/sys/kernel/debug/tracing# cat /proc/fs/fscache/cookies
COOKIE VOLUME REF ACT ACC S FL DEF
======== ======== === === === = == ================
00000002 00000001 1 0 0 - 4008 302559bec76a7924,
0a13e961000000000a13e96100000000d01f4719d01f4719
00000003 00000001 1 0 0 - 4000 0000000000640090,
37630162000000003763016200000000e8650f119c49f411
00000004 00000001 1 0 0 - 4000 00000000001800f0,
244e016200000000244e01620000000044975123c042f525
00000005 00000001 1 0 0 - 4000 00000000007000a0,
ea92e96100000000ea92e96100000000acee2035acee2035
00000006 00000001 1 0 0 - 4000 00000000007000c0,
ad92e96100000000ad92e96100000000407da317407da317
00000007 00000001 1 0 0 - 4000 00000000002800e0,
4aeaf361000000004aeaf3610000000078c77b0d6850dc1f
00000008 00000001 1 0 0 - 4008 0000000000140080,
df92136200000000df92136200000000b8e0f30eb8e0f30e
00000009 00000001 1 0 0 - 4008 00000000001400e0,
d39d136200000000d39d136200000000f4e6e51bf4e6e51b
0000000a 00000001 1 0 0 - 4008 0000000000140090,
d99d136200000000d99d136200000000dcd77d28dcd77d28
0000000b 00000001 1 0 0 - 4008 0000000000540080,
cdd21c6200000000cdd21c62000000009c8cd90c9c8cd90c
0000000c 00000001 1 0 0 - 4008 00000000005400c0,
cdd21c6200000000cdd21c6200000000f44b440df44b440d
0000000d 00000001 1 0 0 - 4008 00000000005400a0,
cdd21c6200000000cdd21c62000000005487b50f5487b50f
0000000e 00000001 1 0 0 - 4008 00000000005400e0,
ebd21c6200000000ebd21c6200000000c07c1800c07c1800
0000000f 00000001 1 0 0 - 4008 0000000000540090,
ebd21c6200000000ebd21c620000000094fc730094fc7300
00000010 00000001 1 0 0 - 4008 00000000005400d0,
ebd21c6200000000ebd21c6200000000bcb78902bcb78902
00000011 00000001 1 0 0 - 4008 00000000005400b0,
29d31c620000000029d31c62000000002c02e8252c02e825
00000012 00000001 1 0 0 - 4008 00000000005400f0,
29d31c620000000029d31c6200000000c83fae26c83fae26
00000013 00000001 1 0 0 - 4008 0000000000540088,
29d31c620000000029d31c6200000000e4fcc328e4fcc328
00000014 00000001 1 0 0 - 4008 00000000005400c8,
3bd31c62000000003bd31c6200000000747b780b747b780b
00000015 00000001 1 0 0 - 4008 00000000005400a8,
3bd31c62000000003bd31c6200000000ecf57e0decf57e0d
00000016 00000001 1 0 0 - 4008 00000000005400e8,
b0d51c6200000000b0d51c62000000002005e5092005e509
00000017 00000001 1 0 0 - 4008 0000000000540098,
b0d51c6200000000b0d51c620000000034035f0a34035f0a
00000018 00000001 1 0 0 - 4008 00000000005400d8,
b0d51c6200000000b0d51c62000000001cfdc00c1cfdc00c
00000019 00000001 1 0 0 - 4008 00000000005400b8,
50d61c620000000050d61c62000000004453d0384453d038
0000001a 00000001 1 0 0 - 4008 00000000005400f8,
50d61c620000000050d61c6200000000d4113b39d4113b39
0000001b 00000001 1 0 0 - 4008 0000000000540084,
51d61c620000000051d61c62000000002042020020420200
0000001c 00000001 1 0 0 - 4008 00000000005400c4,
16d71c620000000016d71c62000000009ceb0d019ceb0d01
0000001d 00000001 1 0 0 - 4008 00000000005400a4,
16d71c620000000016d71c6200000000dcae7801dcae7801
0000001e 00000001 1 0 0 - 4008 00000000005400e4,
16d71c620000000016d71c6200000000ec2af903ec2af903
I have enabled below fscache and cachefiles related tracepoints. But
nothing is getting printed in trace o/p.
echo 1 >/sys/kernel/debug/tracing/events/fscache/fscache_access/enable
echo 1 >/sys/kernel/debug/tracing/events/fscache/fscache_active/enable
echo 1 >/sys/kernel/debug/tracing/events/cachefiles/cachefiles_coherency/enable
echo 1 >/sys/kernel/debug/tracing/events/cachefiles/cachefiles_read/enable
echo 1 >/sys/kernel/debug/tracing/events/cachefiles/cachefiles_write/enable
echo 1 >/sys/kernel/debug/tracing/events/cachefiles/cachefiles_io_error/enable
echo 1 >/sys/kernel/debug/tracing/events/cachefiles/cachefiles_vfs_error/enable
echo 1 > events/cachefiles/cachefiles_vol_coherency/enable
Regards,
Rohith
On Mon, Feb 14, 2022 at 10:03 PM David Howells <dhowells at redhat.com> wrote:
>
> Rohith Surabattula <rohiths.msft at gmail.com> wrote:
>
> > I have tested netfs integration with fsc mount option enabled. But, I
> > observed function "netfs_cache_prepare_read" always returns
> > "NETFS_DOWNLOAD_FROM_SERVER" because cres->ops(i.e cachefiles
> > operations) is not set.
>
> I see it download from the server and write to the cache:
>
> # cat /proc/fs/fscache/stats
> ...
> IO : rd=0 wr=4 <---- no reads, four writes made
> RdHelp : DR=0 RA=4 RP=0 WB=0 WBZ=0 rr=0 sr=0
> RdHelp : ZR=0 sh=0 sk=0
> RdHelp : DL=4 ds=4 df=0 di=0
> RdHelp : RD=0 rs=0 rf=0
> RdHelp : WR=4 ws=4 wf=0
>
> Turning on the cachefiles_vol_coherency tracepoint, I see:
>
> kworker/2:2-1040 [002] ..... 585.499799: cachefiles_vol_coherency: V=00000003 VOL BAD cmp B=480004
> kworker/2:2-1040 [002] ..... 585.499872: cachefiles_vol_coherency: V=00000003 VOL SET ok B=480005
>
> every time I unmount and mount again. One of the fields is different each
> time.
>
> Using the netfs tracepoints, I can see the download being made from the server
> and then the subsequent write to the cache:
>
> md5sum-4689 [003] ..... 887.382290: netfs_read: R=00000005 READAHEAD c=0000004e ni=86 s=0 20000
> md5sum-4689 [003] ..... 887.383076: netfs_read: R=00000005 EXPANDED c=0000004e ni=86 s=0 400000
> md5sum-4689 [003] ..... 887.383252: netfs_sreq: R=00000005[0] PREP DOWN f=01 s=0 0/400000 e=0
> md5sum-4689 [003] ..... 887.383252: netfs_sreq: R=00000005[0] SUBMT DOWN f=01 s=0 0/400000 e=0
> cifsd-4687 [002] ..... 887.394926: netfs_sreq: R=00000005[0] TERM DOWN f=03 s=0 400000/400000 e=0
> cifsd-4687 [002] ..... 887.394928: netfs_rreq: R=00000005 ASSESS f=22
> cifsd-4687 [002] ..... 887.394928: netfs_rreq: R=00000005 UNLOCK f=22
> kworker/u8:4-776 [000] ..... 887.395000: netfs_rreq: R=00000005 WRITE f=02
> kworker/u8:4-776 [000] ..... 887.395005: netfs_sreq: R=00000005[0] WRITE DOWN f=03 s=0 400000/400000 e=0
> kworker/3:2-1001 [003] ..... 887.627881: netfs_sreq: R=00000005[0] WTERM DOWN f=03 s=0 400000/400000 e=0
> kworker/3:2-1001 [003] ..... 887.628163: netfs_rreq: R=00000005 DONE f=02
> kworker/3:2-1001 [003] ..... 887.628165: netfs_sreq: R=00000005[0] FREE DOWN f=03 s=0 400000/400000 e=0
> kworker/u8:4-776 [000] ..... 887.628216: netfs_rreq: R=00000005 FREE f=02
>
> Can you mount a cifs share with "-o fsc", read a file and then look in
> /proc/fs/fscache/cookies and /proc/fs/fscache/stats for me?
>
> David
>
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