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afs: Get an AFS3 ACL as an xattr 

Implement an xattr on AFS files called "afs.acl" that retrieves a file's
ACL.  It returns the raw AFS3 ACL from the result of calling FS.FetchACL,
leaving any interpretation to userspace.

Note that whilst YFS servers will respond to FS.FetchACL, this will render
a more-advanced YFS ACL down.  Use "afs.yfs.acl" instead for that.

Signed-off-by: David Howells <dhowells@redhat.com>
hifive-unleashed-5.2
David Howells 2019-04-25 14:26:52 +01:00
parent a2f611a3dc
commit 260f082bae
5 changed files with 184 additions and 0 deletions
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1
fs/afs/afs_fs.h
View File

@ -17,6 +17,7 @@
enum AFS_FS_Operations {
FSFETCHDATA = 130, /* AFS Fetch file data */
FSFETCHACL = 131, /* AFS Fetch file ACL */
FSFETCHSTATUS = 132, /* AFS Fetch file status */
FSSTOREDATA = 133, /* AFS Store file data */
FSSTORESTATUS = 135, /* AFS Store file status */

122
fs/afs/fsclient.c
View File

@ -2391,3 +2391,125 @@ int afs_fs_inline_bulk_status(struct afs_fs_cursor *fc,
afs_make_call(&fc->ac, call, GFP_NOFS);
return afs_wait_for_call_to_complete(call, &fc->ac);
}
/*
* deliver reply data to an FS.FetchACL
*/
static int afs_deliver_fs_fetch_acl(struct afs_call *call)
{
struct afs_vnode *vnode = call->reply[1];
struct afs_acl *acl;
const __be32 *bp;
unsigned int size;
int ret;
_enter("{%u}", call->unmarshall);
switch (call->unmarshall) {
case 0:
afs_extract_to_tmp(call);
call->unmarshall++;
/* extract the returned data length */
case 1:
ret = afs_extract_data(call, true);
if (ret < 0)
return ret;
size = call->count2 = ntohl(call->tmp);
size = round_up(size, 4);
acl = kmalloc(struct_size(acl, data, size), GFP_KERNEL);
if (!acl)
return -ENOMEM;
call->reply[0] = acl;
acl->size = call->count2;
afs_extract_begin(call, acl->data, size);
call->unmarshall++;
/* extract the returned data */
case 2:
ret = afs_extract_data(call, true);
if (ret < 0)
return ret;
afs_extract_to_buf(call, (21 + 6) * 4);
call->unmarshall++;
/* extract the metadata */
case 3:
ret = afs_extract_data(call, false);
if (ret < 0)
return ret;
bp = call->buffer;
ret = afs_decode_status(call, &bp, &vnode->status, vnode,
&vnode->status.data_version, NULL);
if (ret < 0)
return ret;
xdr_decode_AFSVolSync(&bp, call->reply[2]);
call->unmarshall++;
case 4:
break;
}
_leave(" = 0 [done]");
return 0;
}
static void afs_destroy_fs_fetch_acl(struct afs_call *call)
{
kfree(call->reply[0]);
afs_flat_call_destructor(call);
}
/*
* FS.FetchACL operation type
*/
static const struct afs_call_type afs_RXFSFetchACL = {
.name = "FS.FetchACL",
.op = afs_FS_FetchACL,
.deliver = afs_deliver_fs_fetch_acl,
.destructor = afs_destroy_fs_fetch_acl,
};
/*
* Fetch the ACL for a file.
*/
struct afs_acl *afs_fs_fetch_acl(struct afs_fs_cursor *fc)
{
struct afs_vnode *vnode = fc->vnode;
struct afs_call *call;
struct afs_net *net = afs_v2net(vnode);
__be32 *bp;
_enter(",%x,{%llx:%llu},,",
key_serial(fc->key), vnode->fid.vid, vnode->fid.vnode);
call = afs_alloc_flat_call(net, &afs_RXFSFetchACL, 16, (21 + 6) * 4);
if (!call) {
fc->ac.error = -ENOMEM;
return ERR_PTR(-ENOMEM);
}
call->key = fc->key;
call->reply[0] = NULL;
call->reply[1] = vnode;
call->reply[2] = NULL; /* volsync */
call->ret_reply0 = true;
/* marshall the parameters */
bp = call->request;
bp[0] = htonl(FSFETCHACL);
bp[1] = htonl(vnode->fid.vid);
bp[2] = htonl(vnode->fid.vnode);
bp[3] = htonl(vnode->fid.unique);
call->cb_break = fc->cb_break;
afs_use_fs_server(call, fc->cbi);
trace_afs_make_fs_call(call, &vnode->fid);
afs_make_call(&fc->ac, call, GFP_KERNEL);
return (struct afs_acl *)afs_wait_for_call_to_complete(call, &fc->ac);
}

7
fs/afs/internal.h
View File

@ -977,6 +977,13 @@ extern int afs_fs_fetch_status(struct afs_fs_cursor *, struct afs_net *,
struct afs_fid *, struct afs_file_status *,
struct afs_callback *, struct afs_volsync *);
struct afs_acl {
u32 size;
u8 data[];
};
extern struct afs_acl *afs_fs_fetch_acl(struct afs_fs_cursor *);
/*
* fs_probe.c
*/

53
fs/afs/xattr.c
View File

@ -16,6 +16,7 @@
#include "internal.h"
static const char afs_xattr_list[] =
"afs.acl\0"
"afs.cell\0"
"afs.fid\0"
"afs.volume";
@ -33,6 +34,57 @@ ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size)
return sizeof(afs_xattr_list);
}
/*
* Get a file's ACL.
*/
static int afs_xattr_get_acl(const struct xattr_handler *handler,
struct dentry *dentry,
struct inode *inode, const char *name,
void *buffer, size_t size)
{
struct afs_fs_cursor fc;
struct afs_vnode *vnode = AFS_FS_I(inode);
struct afs_acl *acl = NULL;
struct key *key;
int ret;
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key))
return PTR_ERR(key);
ret = -ERESTARTSYS;
if (afs_begin_vnode_operation(&fc, vnode, key)) {
while (afs_select_fileserver(&fc)) {
fc.cb_break = afs_calc_vnode_cb_break(vnode);
acl = afs_fs_fetch_acl(&fc);
}
afs_check_for_remote_deletion(&fc, fc.vnode);
afs_vnode_commit_status(&fc, vnode, fc.cb_break);
ret = afs_end_vnode_operation(&fc);
}
if (ret == 0) {
ret = acl->size;
if (size > 0) {
ret = -ERANGE;
if (acl->size > size)
return -ERANGE;
memcpy(buffer, acl->data, acl->size);
ret = acl->size;
}
kfree(acl);
}
key_put(key);
return ret;
}
static const struct xattr_handler afs_xattr_afs_acl_handler = {
.name = "afs.acl",
.get = afs_xattr_get_acl,
};
/*
* Get the name of the cell on which a file resides.
*/
@ -123,6 +175,7 @@ static const struct xattr_handler afs_xattr_afs_volume_handler = {
};
const struct xattr_handler *afs_xattr_handlers[] = {
&afs_xattr_afs_acl_handler,
&afs_xattr_afs_cell_handler,
&afs_xattr_afs_fid_handler,
&afs_xattr_afs_volume_handler,

1
include/trace/events/afs.h
View File

@ -33,6 +33,7 @@ enum afs_call_trace {
enum afs_fs_operation {
afs_FS_FetchData = 130, /* AFS Fetch file data */
afs_FS_FetchACL = 131, /* AFS Fetch file ACL */
afs_FS_FetchStatus = 132, /* AFS Fetch file status */
afs_FS_StoreData = 133, /* AFS Store file data */
afs_FS_StoreStatus = 135, /* AFS Store file status */