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authorChuck Lever <chuck.lever@oracle.com>2018-07-27 11:19:10 -0400
committerJ. Bruce Fields <bfields@redhat.com>2018-08-09 16:11:21 -0400
commit11b4d66ea3313d9b03a83b80458ddee64990e3c3 (patch)
treed2558f204fe319fc365c07756bfd48a055a0580d /fs/nfsd
parent3fd9557aec919e2db99365ad5a2c00d04ae8893c (diff)
downloadlinux-11b4d66ea3313d9b03a83b80458ddee64990e3c3.tar.bz2
NFSD: Handle full-length symlinks
I've given up on the idea of zero-copy handling of SYMLINK on the server side. This is because the Linux VFS symlink API requires the symlink pathname to be in a NUL-terminated kmalloc'd buffer. The NUL-termination is going to be problematic (watching out for landing on a page boundary and dealing with a 4096-byte pathname). I don't believe that SYMLINK creation is on a performance path or is requested frequently enough that it will cause noticeable CPU cache pollution due to data copies. There will be two places where a transport callout will be necessary to fill in the rqstp: one will be in the svc_fill_symlink_pathname() helper that is used by NFSv2 and NFSv3, and the other will be in nfsd4_decode_create(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs3proc.c2
-rw-r--r--fs/nfsd/nfsproc.c2
2 files changed, 4 insertions, 0 deletions
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 8d1c2d1a159b..9eb8086ea841 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -290,6 +290,7 @@ nfsd3_proc_symlink(struct svc_rqst *rqstp)
RETURN_STATUS(nfserr_nametoolong);
argp->tname = svc_fill_symlink_pathname(rqstp, &argp->first,
+ page_address(rqstp->rq_arg.pages[0]),
argp->tlen);
if (IS_ERR(argp->tname))
RETURN_STATUS(nfserrno(PTR_ERR(argp->tname)));
@@ -303,6 +304,7 @@ nfsd3_proc_symlink(struct svc_rqst *rqstp)
fh_init(&resp->fh, NFS3_FHSIZE);
nfserr = nfsd_symlink(rqstp, &resp->dirfh, argp->fname, argp->flen,
argp->tname, &resp->fh);
+ kfree(argp->tname);
RETURN_STATUS(nfserr);
}
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index a6faee562b31..0d20fd161225 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -454,6 +454,7 @@ nfsd_proc_symlink(struct svc_rqst *rqstp)
return nfserr_nametoolong;
argp->tname = svc_fill_symlink_pathname(rqstp, &argp->first,
+ page_address(rqstp->rq_arg.pages[0]),
argp->tlen);
if (IS_ERR(argp->tname))
return nfserrno(PTR_ERR(argp->tname));
@@ -466,6 +467,7 @@ nfsd_proc_symlink(struct svc_rqst *rqstp)
nfserr = nfsd_symlink(rqstp, &argp->ffh, argp->fname, argp->flen,
argp->tname, &newfh);
+ kfree(argp->tname);
fh_put(&argp->ffh);
fh_put(&newfh);
return nfserr;