mirror of https://gitee.com/openkylin/linux.git
3b2d4dcf71
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:
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||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| acl.h | ||
| auth.c | ||
| auth.h | ||
| blocklayout.c | ||
| blocklayoutxdr.c | ||
| blocklayoutxdr.h | ||
| cache.h | ||
| current_stateid.h | ||
| export.c | ||
| export.h | ||
| fault_inject.c | ||
| flexfilelayout.c | ||
| flexfilelayoutxdr.c | ||
| flexfilelayoutxdr.h | ||
| idmap.h | ||
| lockd.c | ||
| netns.h | ||
| nfs2acl.c | ||
| nfs3acl.c | ||
| nfs3proc.c | ||
| nfs3xdr.c | ||
| nfs4acl.c | ||
| nfs4callback.c | ||
| nfs4idmap.c | ||
| nfs4layouts.c | ||
| nfs4proc.c | ||
| nfs4recover.c | ||
| nfs4state.c | ||
| nfs4xdr.c | ||
| nfscache.c | ||
| nfsctl.c | ||
| nfsd.h | ||
| nfsfh.c | ||
| nfsfh.h | ||
| nfsproc.c | ||
| nfssvc.c | ||
| nfsxdr.c | ||
| pnfs.h | ||
| state.h | ||
| stats.c | ||
| stats.h | ||
| trace.c | ||
| trace.h | ||
| vfs.c | ||
| vfs.h | ||
| xdr.h | ||
| xdr3.h | ||
| xdr4.h | ||
| xdr4cb.h | ||