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| author | Jeff Layton <jlayton@redhat.com> | 2007-05-09 13:34:50 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 23:30:54 +0400 |
| commit | cd123012d99fde4759500fee611e724e4f3016e3 (patch) | |
| tree | a947c5e4210a2a51ea6619b3e127650feaa00421 /fs/nfsd/nfs3proc.c | |
| parent | 669716433598a1498049e75a84a5aaf69c8da173 (diff) | |
| download | linux-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 'fs/nfsd/nfs3proc.c')
| -rw-r--r-- | fs/nfsd/nfs3proc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index 7f5bad0393b1..eac82830bfd7 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -177,7 +177,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp, struct nfsd3_readargs *argp, if (max_blocksize < resp->count) resp->count = max_blocksize; - svc_reserve(rqstp, ((1 + NFS3_POST_OP_ATTR_WORDS + 3)<<2) + resp->count +4); + svc_reserve_auth(rqstp, ((1 + NFS3_POST_OP_ATTR_WORDS + 3)<<2) + resp->count +4); fh_copy(&resp->fh, &argp->fh); nfserr = nfsd_read(rqstp, &resp->fh, NULL, |