48180e15d3
When logical address of a regular extent is 0, the extent is sparse and consists of all zeros. Without this when sparse extents are used in a file reading fails with Cannot map logical address 0 to physical Signed-off-by: Marek Behún <marek.behun@nic.cz>
127 lines
2.4 KiB
C
127 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* BTRFS filesystem implementation for U-Boot
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*
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* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
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*/
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#include "btrfs.h"
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#include <malloc.h>
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#include <memalign.h>
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u64 btrfs_read_extent_inline(struct btrfs_path *path,
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struct btrfs_file_extent_item *extent, u64 offset,
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u64 size, char *out)
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{
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u32 clen, dlen, orig_size = size, res;
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const char *cbuf;
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char *dbuf;
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const int data_off = offsetof(struct btrfs_file_extent_item,
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disk_bytenr);
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clen = btrfs_path_item_size(path) - data_off;
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cbuf = (const char *) extent + data_off;
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dlen = extent->ram_bytes;
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if (offset > dlen)
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return -1ULL;
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if (size > dlen - offset)
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size = dlen - offset;
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if (extent->compression == BTRFS_COMPRESS_NONE) {
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memcpy(out, cbuf + offset, size);
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return size;
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}
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if (dlen > orig_size) {
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dbuf = malloc(dlen);
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if (!dbuf)
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return -1ULL;
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} else {
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dbuf = out;
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}
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res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
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if (res == -1 || res != dlen)
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goto err;
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if (dlen > orig_size) {
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memcpy(out, dbuf + offset, size);
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free(dbuf);
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} else if (offset) {
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memmove(out, dbuf + offset, size);
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}
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return size;
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err:
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if (dlen > orig_size)
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free(dbuf);
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return -1ULL;
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}
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u64 btrfs_read_extent_reg(struct btrfs_path *path,
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struct btrfs_file_extent_item *extent, u64 offset,
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u64 size, char *out)
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{
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u64 physical, clen, dlen, orig_size = size;
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u32 res;
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char *cbuf, *dbuf;
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clen = extent->disk_num_bytes;
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dlen = extent->num_bytes;
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if (offset > dlen)
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return -1ULL;
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if (size > dlen - offset)
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size = dlen - offset;
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/* sparse extent */
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if (extent->disk_bytenr == 0) {
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memset(out, 0, size);
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return size;
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}
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physical = btrfs_map_logical_to_physical(extent->disk_bytenr);
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if (physical == -1ULL)
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return -1ULL;
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if (extent->compression == BTRFS_COMPRESS_NONE) {
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physical += extent->offset + offset;
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if (!btrfs_devread(physical, size, out))
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return -1ULL;
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return size;
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}
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cbuf = malloc_cache_aligned(dlen > size ? clen + dlen : clen);
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if (!cbuf)
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return -1ULL;
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if (dlen > orig_size)
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dbuf = cbuf + clen;
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else
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dbuf = out;
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if (!btrfs_devread(physical, clen, cbuf))
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goto err;
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res = btrfs_decompress(extent->compression, cbuf, clen, dbuf, dlen);
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if (res == -1)
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goto err;
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if (dlen > orig_size)
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memcpy(out, dbuf + offset, size);
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else
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memmove(out, dbuf + offset, size);
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free(cbuf);
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return res;
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err:
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free(cbuf);
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return -1ULL;
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}
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