diff options
author | Jeff Layton <jlayton@redhat.com> | 2007-05-09 09:34:50 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 19:30:54 (GMT) |
commit | cd123012d99fde4759500fee611e724e4f3016e3 (patch) | |
tree | a947c5e4210a2a51ea6619b3e127650feaa00421 /include/linux/sunrpc/svc.h | |
parent | 669716433598a1498049e75a84a5aaf69c8da173 (diff) | |
download | linux-fsl-qoriq-cd123012d99fde4759500fee611e724e4f3016e3.tar.xz |
RPC: add wrapper for svc_reserve to account for checksum
When the kernel calls svc_reserve to downsize the expected size of an RPC
reply, it fails to account for the possibility of a checksum at the end of
the packet. If a client mounts a NFSv2/3 with sec=krb5i/p, and does I/O
then you'll generally see messages similar to this in the server's ring
buffer:
RPC request reserved 164 but used 208
While I was never able to verify it, I suspect that this problem is also
the root cause of some oopses I've seen under these conditions:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=227726
This is probably also a problem for other sec= types and for NFSv4. The
large reserved size for NFSv4 compound packets seems to generally paper
over the problem, however.
This patch adds a wrapper for svc_reserve that accounts for the possibility
of a checksum. It also fixes up the appropriate callers of svc_reserve to
call the wrapper. For now, it just uses a hardcoded value that I
determined via testing. That value may need to be revised upward as things
change, or we may want to eventually add a new auth_op that attempts to
calculate this somehow.
Unfortunately, there doesn't seem to be a good way to reliably determine
the expected checksum length prior to actually calculating it, particularly
with schemes like spkm3.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sunrpc/svc.h')
-rw-r--r-- | include/linux/sunrpc/svc.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index 35fa4d5..4a7ae8a 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -396,4 +396,23 @@ char * svc_print_addr(struct svc_rqst *, char *, size_t); #define RPC_MAX_ADDRBUFLEN (63U) +/* + * When we want to reduce the size of the reserved space in the response + * buffer, we need to take into account the size of any checksum data that + * may be at the end of the packet. This is difficult to determine exactly + * for all cases without actually generating the checksum, so we just use a + * static value. + */ +static inline void +svc_reserve_auth(struct svc_rqst *rqstp, int space) +{ + int added_space = 0; + + switch(rqstp->rq_authop->flavour) { + case RPC_AUTH_GSS: + added_space = RPC_MAX_AUTH_SIZE; + } + return svc_reserve(rqstp, space + added_space); +} + #endif /* SUNRPC_SVC_H */ |