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nfsd4: don't try to encode conflicting owner if low on space

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I ran into this corner case in testing: in theory clients can provide
state owners up to 1024 bytes long.  In the sessions case there might be
a risk of this pushing us over the DRC slot size.

The conflicting owner isn't really that important, so let's humor a
client that provides a small maxresponsize_cached by allowing ourselves
to return without the conflicting owner instead of outright failing the
operation.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2014-03-10 12:19:10 -04:00
commit 8c7424cff6
2 changed files with 15 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

3
fs/nfsd/nfs4proc.c
View file

@ -1432,7 +1432,8 @@ out:
#define op_encode_change_info_maxsz (5)
#define nfs4_fattr_bitmap_maxsz (4)
#define op_encode_lockowner_maxsz (1 + XDR_QUADLEN(IDMAP_NAMESZ))
/* We'll fall back on returning no lockowner if run out of space: */
#define op_encode_lockowner_maxsz (0)
#define op_encode_lock_denied_maxsz (8 + op_encode_lockowner_maxsz)
#define nfs4_owner_maxsz (1 + XDR_QUADLEN(IDMAP_NAMESZ))

16
fs/nfsd/nfs4xdr.c
View file

@ -2878,9 +2878,20 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
struct xdr_netobj *conf = &ld->ld_owner;
__be32 *p;
again:
p = xdr_reserve_space(xdr, 32 + XDR_LEN(conf->len));
if (!p)
if (!p) {
/*
* Don't fail to return the result just because we can't
* return the conflicting open:
*/
if (conf->len) {
conf->len = 0;
conf->data = NULL;
goto again;
}
return nfserr_resource;
}
WRITE64(ld->ld_start);
WRITE64(ld->ld_length);
WRITE32(ld->ld_type);
@ -2888,7 +2899,6 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld)
WRITEMEM(&ld->ld_clientid, 8);
WRITE32(conf->len);
WRITEMEM(conf->data, conf->len);
kfree(conf->data);
} else { /* non - nfsv4 lock in conflict, no clientid nor owner */
WRITE64((u64)0); /* clientid */
WRITE32(0); /* length of owner name */
@ -2905,7 +2915,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo
nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);
else if (nfserr == nfserr_denied)
nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);
kfree(lock->lk_denied.ld_owner.data);
return nfserr;
}