linux/fs/nfsd
Paul Menzel 3b2d4dcf71 nfsd: Fix overflow causing non-working mounts on 1 TB machines
Since commit 10a68cdf10 (nfsd: fix performance-limiting session
calculation) (Linux 5.1-rc1 and 4.19.31), shares from NFS servers with
1 TB of memory cannot be mounted anymore. The mount just hangs on the
client.

The gist of commit 10a68cdf10 is the change below.

    -avail = clamp_t(int, avail, slotsize, avail/3);
    +avail = clamp_t(int, avail, slotsize, total_avail/3);

Here are the macros.

    #define min_t(type, x, y)       __careful_cmp((type)(x), (type)(y), <)
    #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)

`total_avail` is 8,434,659,328 on the 1 TB machine. `clamp_t()` casts
the values to `int`, which for 32-bit integers can only hold values
−2,147,483,648 (−2^31) through 2,147,483,647 (2^31 − 1).

`avail` (in the function signature) is just 65536, so that no overflow
was happening. Before the commit the assignment would result in 21845,
and `num = 4`.

When using `total_avail`, it is causing the assignment to be
18446744072226137429 (printed as %lu), and `num` is then 4164608182.

My next guess is, that `nfsd_drc_mem_used` is then exceeded, and the
server thinks there is no memory available any more for this client.

Updating the arguments of `clamp_t()` and `min_t()` to `unsigned long`
fixes the issue.

Now, `avail = 65536` (before commit 10a68cdf10 `avail = 21845`), but
`num = 4` remains the same.

Fixes: c54f24e338 (nfsd: fix performance-limiting session calculation)
Cc: stable@vger.kernel.org
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-07-03 17:51:31 -04:00
..
acl.h
auth.c nfsd: auth: Fix gid sorting when rootsquash enabled 2018-01-22 20:13:07 -08:00
auth.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
blocklayout.c vfs/y2038: inode timestamps conversion to timespec64 2018-06-15 07:31:07 +09:00
blocklayoutxdr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
blocklayoutxdr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cache.h knfsd: Improve lookup performance in the duplicate reply cache using an rbtree 2018-10-29 16:58:04 -04:00
current_stateid.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
export.c nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
export.h knfsd: Allow lockless lookups of the exports 2018-10-29 16:58:04 -04:00
fault_inject.c Lots of good bugfixes, including: 2017-11-18 11:22:04 -08:00
flexfilelayout.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
flexfilelayoutxdr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
flexfilelayoutxdr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idmap.h nfsd: Remove duplicate define of IDMAP_NAMESZ/IDMAP_TYPE_xx 2015-07-20 14:58:46 -04:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
lockd.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
netns.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
nfs2acl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nfs3acl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nfs3proc.c nfsd/nfsd3_proc_readdir: fix buffer count and page pointers 2019-04-05 19:57:24 -04:00
nfs3xdr.c nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
nfs4acl.c nfsd: check permissions when setting ACLs 2016-06-24 12:11:52 -04:00
nfs4callback.c This pull consists mostly of nfsd container work: 2019-05-15 18:21:43 -07:00
nfs4idmap.c nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
nfs4layouts.c nfsd: update callback done processing 2019-05-03 11:01:38 -04:00
nfs4proc.c This pull consists mostly of nfsd container work: 2019-05-15 18:21:43 -07:00
nfs4recover.c This pull consists mostly of nfsd container work: 2019-05-15 18:21:43 -07:00
nfs4state.c nfsd: Fix overflow causing non-working mounts on 1 TB machines 2019-07-03 17:51:31 -04:00
nfs4xdr.c nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
nfscache.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
nfsctl.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
nfsd.h nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
nfsfh.c nfsd: use true and false for boolean values 2018-08-09 16:11:21 -04:00
nfsfh.h This request is late, apologies. 2018-02-08 15:18:32 -08:00
nfsproc.c NFSD: Handle full-length symlinks 2018-08-09 16:11:21 -04:00
nfssvc.c lockd: Pass the user cred from knfsd when starting the lockd server 2019-04-24 09:46:35 -04:00
nfsxdr.c nfsd: knfsd must use the container user namespace 2019-04-24 09:46:35 -04:00
pnfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
state.h nfsd: make nfs4_client_reclaim use an xdr_netobj instead of a fixed char array 2019-04-24 09:46:34 -04:00
stats.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace.c nfsd: move include of state.h from trace.c to trace.h 2015-10-23 15:57:29 -04:00
trace.h nfsd: Trace NFSv4 COMPOUND execution 2018-04-03 15:08:15 -04:00
vfs.c nfsd: fh_drop_write in nfsd_unlink 2019-04-24 09:46:35 -04:00
vfs.h nfsd: allow fh_want_write to be called twice 2019-04-24 09:46:35 -04:00
xdr3.h NFSD: Clean up legacy NFS SYMLINK argument XDR decoders 2018-04-03 15:08:16 -04:00
xdr4.h NFSD introduce async copy feature 2018-09-25 20:34:54 -04:00
xdr4cb.h NFSD CB_OFFLOAD xdr 2018-09-25 20:34:54 -04:00
xdr.h NFSD: Clean up legacy NFS SYMLINK argument XDR decoders 2018-04-03 15:08:16 -04:00