Suresh Jayaraman wrote:
wengang wang wrote:
sometimes HPUX nfs client sends a create request to linux nfs server(v2/v3).
the dump of the request is like:
obj_attributes
mode: value follows
set_it: value follows (1)
mode: 00
uid: no value
set_it: no value (0)
gid: value follows
set_it: value follows (1)
gid: 8030
size: value follows
set_it: value follows (1)
size: 0
atime: don't change
set_it: don't change (0)
mtime: don't change
set_it: don't change (0)
note that mode is 00(havs no rwx privilege even for the owner) and it requires
to set size to 0.
What's the Create Mode in this case? EXCLUSIVE or UNCHECKED?
it's UNCHECKED.
What's the error the server is returning without this patch - ERR_NOTSUPP?
permission deny, that is NFS3ERR_ACCES.
I tested this on 2.6.27.7 with a small program which does this:
fd = open("file", O_CREAT, 0000);
The file creation succeeded with file size set to 0 and the subsequent
chmod too.
tcpdump available for your test?
just after the creation, is the file mode 0000?
May be this could break EXCLUSIVE create mode semantics?
In my case, it's UNCHECKED.
the patch is based on 2.6.27.10.
Signed-off-by: Wengang Wang <wen.gang.wang@xxxxxxxxxx>
--
vfs.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff -up ./fs/nfsd/vfs.c.orig ./fs/nfsd/vfs.c
--- ./fs/nfsd/vfs.c.orig 2008-12-23 14:11:14.000000000 +0800
+++ ./fs/nfsd/vfs.c 2008-12-23 14:54:16.000000000 +0800
@@ -1268,6 +1268,16 @@ nfsd_create(struct svc_rqst *rqstp, stru
switch (type) {
case S_IFREG:
host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL);
+ /* HPUX client sometimes creates a file in mode 000, and set
+ * size to 0. setting size to 0 may fail for some spcific
+ * file systems by the permission checking which requires
+ * WRITE privilege but the mode is 000.
+ * we ignore setting size to 0 for the creation, since it's
+ * just 0 after created.
+ * */
+ if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
+ iap->ia_valid &= ~ATTR_SIZE;
+
break;
case S_IFDIR:
host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
@@ -1421,6 +1431,16 @@ nfsd_create_v3(struct svc_rqst *rqstp, s
/* setattr will sync the child (or not) */
}
+ /* HPUX client sometimes creates a file in mode 000, and set size to 0.
+ * setting size to 0 may fail for some spcific file systems by the
+ * permission checking which requires WRITE privilege but the mode is
+ * 000.
+ * we ignore setting size to 0 for the creation, since it's just 0
+ * after created.
+ * */
+ if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0))
+ iap->ia_valid &= ~ATTR_SIZE;
+
if (createmode == NFS3_CREATE_EXCLUSIVE) {
/* Cram the verifier into atime/mtime */
iap->ia_valid = ATTR_MTIME|ATTR_ATIME
--
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