Evolution-X-Devices/kernel_nothing_sm7325
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ANDROID: fuse: Add support for d_canonical_path

Browse Source 
Allows FUSE to report to inotify that it is acting
as a layered filesystem. The userspace component
returns a string representing the location of the
underlying file. If the string cannot be resolved
into a path, the top level path is returned instead.

Bug: 23904372
Bug: 171780975
Test: inotify on cuttlefish
Change-Id: Iabdca0bbedfbff59e9c820c58636a68ef9683d9f
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Alessio Balsini <balsini@google.com>
This commit is contained in:
Daniel Rosenberg
2016-04-22 00:00:48 -07:00
committed by Greg Kroah-Hartman
parent 854f380681
commit 24ab59f6bb
4 changed files with 48 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
fs/fuse/dev.c
View File

@@ -14,6 +14,7 @@
#include <linux/sched/signal.h>
#include <linux/uio.h>
#include <linux/miscdevice.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/slab.h>
@@ -1899,6 +1900,12 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
err = copy_out_args(cs, req->args, nbytes);
fuse_copy_finish(cs);
if (!err && req->in.h.opcode == FUSE_CANONICAL_PATH) {
char *path = (char *)req->args->out_args[0].value;
path[req->args->out_args[0].size - 1] = 0;
req->out.h.error = kern_path(path, 0, req->args->canonical_path);
}
spin_lock(&fpq->lock);
clear_bit(FR_LOCKED, &req->flags);
if (!fpq->connected)

37
fs/fuse/dir.c
View File

@@ -298,6 +298,42 @@ static int fuse_dentry_delete(const struct dentry *dentry)
return time_before64(fuse_dentry_time(dentry), get_jiffies_64());
}
/*
* Get the canonical path. Since we must translate to a path, this must be done
* in the context of the userspace daemon, however, the userspace daemon cannot
* look up paths on its own. Instead, we handle the lookup as a special case
* inside of the write request.
*/
static void fuse_dentry_canonical_path(const struct path *path, struct path *canonical_path) {
struct inode *inode = d_inode(path->dentry);
struct fuse_conn *fc = get_fuse_conn(inode);
FUSE_ARGS(args);
char *path_name;
int err;
path_name = (char*)__get_free_page(GFP_KERNEL);
if (!path_name)
goto default_path;
args.opcode = FUSE_CANONICAL_PATH;
args.nodeid = get_node_id(inode);
args.in_numargs = 0;
args.out_numargs = 1;
args.out_args[0].size = PATH_MAX;
args.out_args[0].value = path_name;
args.canonical_path = canonical_path;
args.out_argvar = 1;
err = fuse_simple_request(fc, &args);
free_page((unsigned long)path_name);
if (err > 0)
return;
default_path:
canonical_path->dentry = path->dentry;
canonical_path->mnt = path->mnt;
path_get(canonical_path);
}
const struct dentry_operations fuse_dentry_operations = {
.d_revalidate = fuse_dentry_revalidate,
.d_delete = fuse_dentry_delete,
@@ -305,6 +341,7 @@ const struct dentry_operations fuse_dentry_operations = {
.d_init = fuse_dentry_init,
.d_release = fuse_dentry_release,
#endif
.d_canonical_path = fuse_dentry_canonical_path,
};
const struct dentry_operations fuse_root_dentry_operations = {

3
fs/fuse/fuse_i.h
View File

@@ -253,6 +253,9 @@ struct fuse_args {
struct fuse_in_arg in_args[3];
struct fuse_arg out_args[2];
void (*end)(struct fuse_conn *fc, struct fuse_args *args, int error);
/* Path used for completing d_canonical_path */
struct path *canonical_path;
};
struct fuse_args_pages {

1
include/uapi/linux/fuse.h
View File

@@ -465,6 +465,7 @@ enum fuse_opcode {
FUSE_COPY_FILE_RANGE = 47,
FUSE_SETUPMAPPING = 48,
FUSE_REMOVEMAPPING = 49,
FUSE_CANONICAL_PATH = 2016,
/* CUSE specific operations */
CUSE_INIT = 4096,