[ 061/167] [PATCH] nfsd: dont fail unchecked creates of non-special files

Ben Hutchings
2012-05-09T05:53:47Z

From: "J. Bruce Fields" <bfields@redhat.com>

commit 9dc4e6c4d1182d34604ea40fef641775f5b15456 upstream.

Allow a v3 unchecked open of a non-regular file succeed as if it were a
lookup; typically a client in such a case will want to fall back on a
local open, so succeeding and giving it the filehandle is more useful
than failing with nfserr_exist, which makes it appear that nothing at
all exists by that name.

Similarly for v4, on an open-create, return the same errors we would on
an attempt to open a non-regular file, instead of returning
nfserr_exist.

This fixes a problem found doing a v4 open of a symlink with
O_RDONLY|O_CREAT, which resulted in the current client returning EEXIST.

Thanks also to Trond for analysis.

Reported-by: Orion Poplawski <orion@cora.nwra.com>
Tested-by: Orion Poplawski <orion@cora.nwra.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
[bwh: Backported to 3.2: use &resfh, not resfh]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/nfsd/nfs4proc.c | 8 ++++----
fs/nfsd/vfs.c | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)

--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -235,17 +235,17 @@ do_open_lookup(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_o
*/
if (open->op_createmode == NFS4_CREATE_EXCLUSIVE && status == 0)
open->op_bmval[1] = (FATTR4_WORD1_TIME_ACCESS |
- FATTR4_WORD1_TIME_MODIFY);
+ FATTR4_WORD1_TIME_MODIFY);
} else {
status = nfsd_lookup(rqstp, current_fh,
open->op_fname.data, open->op_fname.len, &resfh);
fh_unlock(current_fh);
- if (status)
- goto out;
- status = nfsd_check_obj_isreg(&resfh);
}
if (status)
goto out;
+ status = nfsd_check_obj_isreg(&resfh);
+ if (status)
+ goto out;

if (is_create_with_attrs(open) && open->op_acl != NULL)
do_set_nfs4_acl(rqstp, &resfh, open->op_acl, open->op_bmval);
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1458,7 +1458,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
switch (createmode) {
case NFS3_CREATE_UNCHECKED:
if (! S_ISREG(dchild->d_inode->i_mode))
- err = nfserr_exist;
+ goto out;
else if (truncp) {
/* in nfsv4, we need to treat this case a little
* differently. we don't want to truncate the