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NFSD: Replace RQ_SPLICE_OK in nfsd_read()

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RQ_SPLICE_OK is a bit of a layering violation. Also, a subsequent
patch is going to provide a mechanism for always disabling splice
reads.

Splicing is an issue only for NFS READs, so refactor nfsd_read() to
check the auth type directly instead of relying on an rq_flag
setting.

The new helper will be added into the NFSv4 read path in a
subsequent patch.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2023-11-17 17:14:33 -05:00
parent deb704281f
commit c21fd7a8e8
2 changed files with 26 additions and 1 deletions
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26
fs/nfsd/vfs.c
View File

@ -1209,6 +1209,30 @@ out_nfserr:
return nfserr;
}
/**
* nfsd_read_splice_ok - check if spliced reading is supported
* @rqstp: RPC transaction context
*
* Return values:
* %true: nfsd_splice_read() may be used
* %false: nfsd_splice_read() must not be used
*
* NFS READ normally uses splice to send data in-place. However the
* data in cache can change after the reply's MIC is computed but
* before the RPC reply is sent. To prevent the client from
* rejecting the server-computed MIC in this somewhat rare case, do
* not use splice with the GSS integrity and privacy services.
*/
bool nfsd_read_splice_ok(struct svc_rqst *rqstp)
{
switch (svc_auth_flavor(rqstp)) {
case RPC_AUTH_GSS_KRB5I:
case RPC_AUTH_GSS_KRB5P:
return false;
}
return true;
}
/**
* nfsd_read - Read data from a file
* @rqstp: RPC transaction context
@ -1238,7 +1262,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
return err;
file = nf->nf_file;
if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
if (file->f_op->splice_read && nfsd_read_splice_ok(rqstp))
err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
else
err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);

1
fs/nfsd/vfs.h
View File

@ -114,6 +114,7 @@ __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset,
unsigned long *count, unsigned int base,
u32 *eof);
bool nfsd_read_splice_ok(struct svc_rqst *rqstp);
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long *count,
u32 *eof);