Daniel,
Attached is a diff file with the Mdcache patches I have applied to the V2.7.4. If this
does not work, I'll create a branch on github in a new repo.
Patches applied:
https://github.com/nfs-ganesha/nfs-ganesha/commit/136df4f262c3f9bc29df456...
https://github.com/nfs-ganesha/nfs-ganesha/commit/c98ad1e238f5db9db5ab8db...
https://github.com/nfs-ganesha/nfs-ganesha/commit/f0d5b8d4f6dcce4597459c3...
https://github.com/nfs-ganesha/nfs-ganesha/commit/e11cd5b9f8d6ffbb46061e7...
https://github.com/nfs-ganesha/nfs-ganesha/commit/5439f63b8a1e00f6ff56a4d...
https://github.com/nfs-ganesha/nfs-ganesha/commit/e306c01685b74970ada2259...
Here are the code snippets around the lines of code in the core, after
mdcache_find_keyed_reason gets an error.
Could this happen because after releasing the content_lock another thead acquired the lock
and invalidated the chunk before this thread acquired the lock again?
Potential solution - Unref the chunk before releasing the read lock since it can no longer
be trusted after releasing the lock?
if (!has_write) {
/* We will have to re-find this dirent after we
* re-acquire the lock.
*/
look_ck = dirent->ck;
PTHREAD_RWLOCK_unlock(&directory->content_lock);
PTHREAD_RWLOCK_wrlock(&directory->content_lock);
has_write = true;
/* Dropping the content_lock may have
* invalidated some or all of the dirents and/or
* chunks in this directory. We need to start
* over from this point. look_ck is now correct
* if the dirent is still cached, and we haven't
* changed next_ck, so it's still correct for
* reloading the chunk.
*/
first_pass = true;
>>>>>>>>> Line 3133
mdcache_lru_unref_chunk(chunk);
chunk = NULL;
/* Now we need to look for this dirent again.
* We haven't updated next_ck for this dirent
* yet, so it is the right whence to use for a
* repopulation readdir if the chunk is
* discarded.
*/
goto again;
Thanks,
Vandana
On 7/1/19, 5:40 AM, "Daniel Gryniewicz" <dang(a)redhat.com> wrote:
Hi, Rungta
Because of the patches you've added, none of the line numbers match any
code I have right now. Can you put a branch on github with all your
patches applied, and point me to it?
Thanks,
Daniel
On 6/29/19 8:24 PM, Rungta, Vandana wrote:
Daniel,
Core in mdcache when mdcache_lru_unref_chunk. Ref count is 0.
I started these tests 10 days ago with all the mdcache patches including
the one moving the unref_chunk in readdir_chunked to inside the lock.
The test continues to readdir over 5 million entries while
writing/reading/deleting content. I have 2 test setups – both using a
Windows client that hit this core.
Let me know if there is additional information you need from the cores.
Thanks,
Vandana
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Core was generated by `bin/ganesha.nfsd -f etc/ganesha/ganesha.conf -p
var/run/ganesha.pid -F'.
Program terminated with signal 11, Segmentation fault.
#00x00007fbd14d39c40 in pthread_mutex_lock () from /lib64/libpthread.so.0
Missing separate debuginfos, use: debuginfo-install
sgw-nfs-ganesha-2.0.93.0-1.x86_64
(gdb) bt
#00x00007fbd14d39c40 in pthread_mutex_lock () from /lib64/libpthread.so.0
#10x000000000052af4a in _mdcache_lru_unref_chunk (chunk=0x3836d1a0,
func=0x598a00 <__func__.23678> "mdcache_readdir_chunked", line=3133)
at /src/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_lru.c:2058
#20x0000000000542d84 in mdcache_readdir_chunked (directory=0x664fa280,
whence=37935356, dir_state=0x7fbd0a3dfaf0,
cb=0x4323ed <populate_dirent>, attrmask=0, eod_met=0x7fbd0a3dffeb) at
/src/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_helpers.c:3133
#30x000000000053054c in mdcache_readdir (dir_hdl=0x664fa2b8,
whence=0x7fbd0a3dfad0, dir_state=0x7fbd0a3dfaf0, cb=0x4323ed
<populate_dirent>,
attrmask=0, eod_met=0x7fbd0a3dffeb) at
/src/src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_handle.c:559
#40x0000000000432d14 in fsal_readdir (directory=0x664fa2b8,
cookie=37935356, nbfound=0x7fbd0a3dffec, eod_met=0x7fbd0a3dffeb, attrmask=0,
cb=0x491d35 <nfs3_readdir_callback>, opaque=0x7fbd0a3dffa0) at
/src/src/FSAL/fsal_helper.c:1164
#50x0000000000491b1d in nfs3_readdir (arg=0xa8fc5d48, req=0xa8fc5640,
res=0xa32fbb30) at /src/src/Protocols/NFS/nfs3_readdir.c:289
#60x0000000000457c16 in nfs_rpc_process_request (reqdata=0xa8fc5640) at
/src/src/MainNFSD/nfs_worker_thread.c:1328
#70x00000000004583d5 in nfs_rpc_valid_NFS (req=0xa8fc5640) at
/src/src/MainNFSD/nfs_worker_thread.c:1548
#80x00007fbd15d14034 in svc_vc_decode (req=0xa8fc5640) at
/src/src/libntirpc/src/svc_vc.c:829
#90x000000000044adc5 in nfs_rpc_decode_request (xprt=0x7ae54c90,
xdrs=0x36434390) at /src/src/MainNFSD/nfs_rpc_dispatcher_thread.c:1345
#10 0x00007fbd15d13f45 in svc_vc_recv (xprt=0x7ae54c90) at
/src/src/libntirpc/src/svc_vc.c:802
#11 0x00007fbd15d10689 in svc_rqst_xprt_task (wpe=0x7ae54ea8) at
/src/src/libntirpc/src/svc_rqst.c:769
#12 0x00007fbd15d10ae6 in svc_rqst_epoll_events (sr_rec=0x1acd4d0,
n_events=1) at /src/src/libntirpc/src/svc_rqst.c:941
#13 0x00007fbd15d10d7b in svc_rqst_epoll_loop (sr_rec=0x1acd4d0) at
/src/src/libntirpc/src/svc_rqst.c:1014
#14 0x00007fbd15d10e2e in svc_rqst_run_task (wpe=0x1acd4d0) at
/src/src/libntirpc/src/svc_rqst.c:1050
#15 0x00007fbd15d197f6 in work_pool_thread (arg=0x75491e70) at
/src/src/libntirpc/src/work_pool.c:181
#16 0x00007fbd14d37de5 in start_thread () from /lib64/libpthread.so.0
#17 0x00007fbd1463ef1d in clone () from /lib64/libc.so.6
(gdb) select-frame 1
(gdb) info locals
rc = 32701
refcnt = 171833376
lane = 268435456
qlane = 0xe007e24e0
__func__ = "_mdcache_lru_unref_chunk"
(gdb) info args
chunk = 0x3836d1a0
func = 0x598a00 <__func__.23678> "mdcache_readdir_chunked"
line = 3133
(gdb) print *chunk
$1 = {chunks = {next = 0xed43cd15, prev = 0xa386010002000000}, dirents =
{next = 0x300000003000000, prev = 0x1c00000001000000},
parent = 0x7000000aaaaaaaa, chunk_lru = {q = {next = 0x6e776f6e6b6e75,
prev = 0xfefffffffeffffff}, qid = LRU_ENTRY_NONE, refcnt = 0,
flags = 0, lane = 268435456, cf = 16777283}, reload_ck = 1099511627778,
next_ck = 7236828793636126720, num_entries = 841903471}
(gdb) select-frame 2
(gdb) info locals
status = {major = ERR_FSAL_NOENT, minor = 0}
cb_result = DIR_CONTINUE
entry = 0x0
attrs = {request_mask = 0, valid_mask = 1433550, supported = 1433582,
type = REGULAR_FILE, filesize = 51682, fsid = {major = 0, minor = 0},
acl = 0x0, fileid = 37935372, mode = 493, numlinks = 1, owner =
4294967294, group = 4294967294, rawdev = {major = 0, minor = 0}, atime = {
tv_sec = 1561811134795000, tv_nsec = 0}, creation = {tv_sec = 0, tv_nsec
= 0}, ctime = {tv_sec = 1561811134795000, tv_nsec = 0}, mtime = {
tv_sec = 1561795757, tv_nsec = 842000000}, chgtime = {tv_sec =
1561811134795000, tv_nsec = 0}, spaceused = 51682,
change = 1561811134795000000, generation = 0, expire_time_attr = 60,
fs_locations = 0x0, sec_label = {slai_lfs = {lfs_lfs = 0, lfs_pi = 0},
slai_data = {slai_data_len = 0, slai_data_val = 0x0}}}
dirent = 0xa57f3030
has_write = true
set_first_ck = false
next_ck = 37935375
look_ck = 37935377
chunk = 0x3836d1a0
first_pass = true
eod = false
reload_chunk = false
__func__ = "mdcache_readdir_chunked"
__PRETTY_FUNCTION__ = "mdcache_readdir_chunked"
(gdb) info args
directory = 0x664fa280
whence = 37935356
dir_state = 0x7fbd0a3dfaf0
cb = 0x4323ed <populate_dirent>
attrmask = 0
eod_met = 0x7fbd0a3dffeb
(gdb)