[PATCH] NFSv4: ACL support for the NFSv4 client: read
Client-side support for NFSv4 ACLs. Exports the raw xdr code via the
system.nfs4_acl extended attribute. It is up to userspace to decode the acl
(and to provide correctly xdr'd acls on setxattr), and to convert to/from
POSIX ACLs if desired.
This patch provides only the read support.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1b14d17..c91c099 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2162,6 +2162,60 @@
return 0;
}
+static inline int nfs4_server_supports_acls(struct nfs_server *server)
+{
+ return (server->caps & NFS_CAP_ACLS)
+ && (server->acl_bitmask & ACL4_SUPPORT_ALLOW_ACL)
+ && (server->acl_bitmask & ACL4_SUPPORT_DENY_ACL);
+}
+
+/* Assuming that XATTR_SIZE_MAX is a multiple of PAGE_CACHE_SIZE, and that
+ * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_CACHE_SIZE) bytes on
+ * the stack.
+ */
+#define NFS4ACL_MAXPAGES (XATTR_SIZE_MAX >> PAGE_CACHE_SHIFT)
+
+static void buf_to_pages(const void *buf, size_t buflen,
+ struct page **pages, unsigned int *pgbase)
+{
+ const void *p = buf;
+
+ *pgbase = offset_in_page(buf);
+ p -= *pgbase;
+ while (p < buf + buflen) {
+ *(pages++) = virt_to_page(p);
+ p += PAGE_CACHE_SIZE;
+ }
+}
+
+static ssize_t nfs4_proc_get_acl(struct inode *inode, void *buf, size_t buflen)
+{
+ struct nfs_server *server = NFS_SERVER(inode);
+ struct page *pages[NFS4ACL_MAXPAGES];
+ struct nfs_getaclargs args = {
+ .fh = NFS_FH(inode),
+ .acl_pages = pages,
+ .acl_len = buflen,
+ };
+ size_t resp_len = buflen;
+ struct rpc_message msg = {
+ .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
+ .rpc_argp = &args,
+ .rpc_resp = &resp_len,
+ };
+ int ret;
+
+ if (!nfs4_server_supports_acls(server))
+ return -EOPNOTSUPP;
+ buf_to_pages(buf, buflen, args.acl_pages, &args.acl_pgbase);
+ ret = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
+ if (buflen && resp_len > buflen)
+ return -ERANGE;
+ if (ret == 0)
+ ret = resp_len;
+ return ret;
+}
+
static int
nfs4_async_handle_error(struct rpc_task *task, struct nfs_server *server)
{
@@ -2733,6 +2787,8 @@
}
+#define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"
+
int nfs4_setxattr(struct dentry *dentry, const char *key, const void *buf,
size_t buflen, int flags)
{
@@ -2746,18 +2802,23 @@
ssize_t nfs4_getxattr(struct dentry *dentry, const char *key, void *buf,
size_t buflen)
{
- return -EOPNOTSUPP;
+ struct inode *inode = dentry->d_inode;
+
+ if (strcmp(key, XATTR_NAME_NFSV4_ACL) != 0)
+ return -EOPNOTSUPP;
+
+ return nfs4_proc_get_acl(inode, buf, buflen);
}
ssize_t nfs4_listxattr(struct dentry *dentry, char *buf, size_t buflen)
{
- ssize_t len = 0;
+ size_t len = strlen(XATTR_NAME_NFSV4_ACL) + 1;
if (buf && buflen < len)
return -ERANGE;
if (buf)
- memcpy(buf, "", 0);
- return 0;
+ memcpy(buf, XATTR_NAME_NFSV4_ACL, len);
+ return len;
}
struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops = {
