extent-io.c
2.28 KB
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/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include "btrfs.h"
#include <malloc.h>
u64 btrfs_read_extent_inline(struct btrfs_path *path,
struct btrfs_file_extent_item *extent, u64 offset,
u64 size, char *out)
{
u32 clen, dlen, orig_size = size, res;
const char *cbuf;
char *dbuf;
const int data_off = offsetof(struct btrfs_file_extent_item,
disk_bytenr);
clen = btrfs_path_item_size(path) - data_off;
cbuf = (const char *) extent + data_off;
dlen = extent->ram_bytes;
if (offset > dlen)
return -1ULL;
if (size > dlen - offset)
size = dlen - offset;
if (extent->compression == BTRFS_COMPRESS_NONE) {
memcpy(out, cbuf + offset, size);
return size;
}
if (dlen > orig_size) {
dbuf = malloc(dlen);
if (!dbuf)
return -1ULL;
} else {
dbuf = out;
}
res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
if (res == -1 || res != dlen)
goto err;
if (dlen > orig_size) {
memcpy(out, dbuf + offset, size);
free(dbuf);
} else if (offset) {
memmove(out, dbuf + offset, size);
}
return size;
err:
if (dlen > orig_size)
free(dbuf);
return -1ULL;
}
u64 btrfs_read_extent_reg(struct btrfs_path *path,
struct btrfs_file_extent_item *extent, u64 offset,
u64 size, char *out)
{
u64 physical, clen, dlen, orig_size = size;
u32 res;
char *cbuf, *dbuf;
clen = extent->disk_num_bytes;
dlen = extent->num_bytes;
if (offset > dlen)
return -1ULL;
if (size > dlen - offset)
size = dlen - offset;
physical = btrfs_map_logical_to_physical(extent->disk_bytenr);
if (physical == -1ULL)
return -1ULL;
if (extent->compression == BTRFS_COMPRESS_NONE) {
physical += extent->offset + offset;
if (!btrfs_devread(physical, size, out))
return -1ULL;
return size;
}
cbuf = malloc(dlen > size ? clen + dlen : clen);
if (!cbuf)
return -1ULL;
if (dlen > orig_size)
dbuf = cbuf + clen;
else
dbuf = out;
if (!btrfs_devread(physical, clen, cbuf))
goto err;
res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
if (res == -1)
goto err;
if (dlen > orig_size)
memcpy(out, dbuf + offset, size);
else
memmove(out, dbuf + offset, size);
free(cbuf);
return res;
err:
free(cbuf);
return -1ULL;
}