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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2021 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "scrub/array.h"
#include "scrub/blob.h"
#include "scrub/xfile.h"
/*
* XFS Blob Storage
* ================
* Stores and retrieves blobs using a memfd object. Objects are appended to
* the file and the offset is returned as a magic cookie for retrieval.
*/
#define XB_KEY_MAGIC 0xABAADDAD
struct xb_key {
uint32_t magic;
uint32_t size;
loff_t offset;
/* blob comes after here */
} __packed;
/* Initialize a blob storage object. */
struct xblob *
xblob_init(
const char *description)
{
struct xblob *blob;
struct xfile *xfile;
int error;
xfile = xfile_create(description, 0);
if (IS_ERR(xfile))
return ERR_CAST(xfile);
error = -ENOMEM;
blob = kmem_alloc(sizeof(struct xblob), KM_NOFS | KM_MAYFAIL);
if (!blob)
goto out_xfile;
blob->xfile = xfile;
blob->last_offset = PAGE_SIZE;
return blob;
out_xfile:
xfile_destroy(xfile);
return ERR_PTR(error);
}
/* Destroy a blob storage object. */
void
xblob_destroy(
struct xblob *blob)
{
xfile_destroy(blob->xfile);
kmem_free(blob);
}
/* Retrieve a blob. */
int
xblob_get(
struct xblob *blob,
xblob_cookie cookie,
void *ptr,
uint32_t size)
{
struct xb_key key;
int error;
error = xfile_pread(blob->xfile, &key, sizeof(key), cookie);
if (error)
return error;
if (key.magic != XB_KEY_MAGIC || key.offset != cookie) {
ASSERT(0);
return -ENODATA;
}
if (size < key.size) {
ASSERT(0);
return -EFBIG;
}
return xfile_pread(blob->xfile, ptr, key.size, cookie + sizeof(key));
}
/* Store a blob. */
int
xblob_put(
struct xblob *blob,
xblob_cookie *cookie,
void *ptr,
uint32_t size)
{
struct xb_key key = {
.offset = blob->last_offset,
.magic = XB_KEY_MAGIC,
.size = size,
};
loff_t pos = blob->last_offset;
int error;
error = xfile_pwrite(blob->xfile, &key, sizeof(key), pos);
if (error)
goto out_err;
pos += sizeof(key);
error = xfile_pwrite(blob->xfile, ptr, size, pos);
if (error)
goto out_err;
*cookie = blob->last_offset;
blob->last_offset += sizeof(key) + size;
return 0;
out_err:
xfile_discard(blob->xfile, blob->last_offset, pos - 1);
return -ENOMEM;
}
/* Free a blob. */
int
xblob_free(
struct xblob *blob,
xblob_cookie cookie)
{
struct xb_key key;
int error;
error = xfile_pread(blob->xfile, &key, sizeof(key), cookie);
if (error)
return error;
if (key.magic != XB_KEY_MAGIC || key.offset != cookie) {
ASSERT(0);
return -ENODATA;
}
xfile_discard(blob->xfile, cookie, cookie + sizeof(key) + key.size - 1);
return 0;
}
/* How many bytes is this blob storage object consuming? */
loff_t
xblob_bytes(
struct xblob *blob)
{
struct kstat statbuf;
int ret;
ret = xfile_statx(blob->xfile, &statbuf);
if (ret)
return ret;
return statbuf.blocks * 512;
}
/* Drop all the blobs. */
void
xblob_truncate(
struct xblob *blob)
{
xfile_discard(blob->xfile, 0, MAX_LFS_FILESIZE);
blob->last_offset = 0;
}
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