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samba-mirror/source3/modules/vfs_glusterfs_fuse.c
Michael Adam fee8cf326b vfs:glusterfs_fuse: treat ENOATTR as ENOENT
The original implementation of the virtual xattr get_real_filename
in gluster was misusing the ENOENT errno as the authoritative anwer
that the file/dir that we were asking the real filename for does not
exist. But since the getxattr call is done on the parent directory,
this is a violation of the getxattr API which uses ENOENT for the
case that the file/dir that the getxattr call is done against does
not exist.

Now after a recent regression for fuse-mount re-exports due to
gluster mapping ENOENT to ESTALE in the fuse-bridge, the gluster
implementation is changed to more correctly return ENOATTR if the
requested file does not exist.

This patch changes the glusterfs_fuse vfs module to treat ENOATTR as
ENOENT to be fully functional again with latest gluster.

- Without this patch, samba against a new gluster will work correctly,
  but the get_real_filename optimization for a non-existing entry
  is lost.

- With this patch, Samba will not work correctly any more against
  very old gluster servers: Those (correctly) returned ENOATTR
  always, which Samba originally interpreted as EOPNOTSUPP, triggering
  the expensive directory scan. With this patch, ENOATTR is
  interpreted as ENOENT, the authoritative answer that the requested
  entry does not exist, which is wrong unless it really does not exist.

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>

Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Fri Jun 28 12:52:03 UTC 2019 on sn-devel-184
2019-06-28 12:52:03 +00:00

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1.9 KiB
C

/*
Unix SMB/CIFS implementation.
Copyright (c) 2019 Guenther Deschner <gd@samba.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smbd/smbd.h"
#include "system/filesys.h"
#define GLUSTER_NAME_MAX 255
static int vfs_gluster_fuse_get_real_filename(struct vfs_handle_struct *handle,
const char *path,
const char *name,
TALLOC_CTX *mem_ctx,
char **_found_name)
{
int ret;
char key_buf[GLUSTER_NAME_MAX + 64];
char val_buf[GLUSTER_NAME_MAX + 1];
char *found_name = NULL;
if (strlen(name) >= GLUSTER_NAME_MAX) {
errno = ENAMETOOLONG;
return -1;
}
snprintf(key_buf, GLUSTER_NAME_MAX + 64,
"glusterfs.get_real_filename:%s", name);
ret = getxattr(path, key_buf, val_buf, GLUSTER_NAME_MAX + 1);
if (ret == -1) {
if (errno == ENOATTR) {
errno = ENOENT;
}
return -1;
}
found_name = talloc_strdup(mem_ctx, val_buf);
if (found_name == NULL) {
errno = ENOMEM;
return -1;
}
*_found_name = found_name;
return 0;
}
struct vfs_fn_pointers glusterfs_fuse_fns = {
/* File Operations */
.get_real_filename_fn = vfs_gluster_fuse_get_real_filename,
};
static_decl_vfs;
NTSTATUS vfs_glusterfs_fuse_init(TALLOC_CTX *ctx)
{
return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
"glusterfs_fuse", &glusterfs_fuse_fns);
}