diff options
author | Marek BehĂșn | 2017-09-03 17:00:28 +0200 |
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committer | Tom Rini | 2017-10-02 21:52:17 -0400 |
commit | 21a14facb1494592c3ad4874c6a00539d15a29cf (patch) | |
tree | 96b0f5d1bfcbddff721717c6609ec401bd594ccf /fs/btrfs/compression.c | |
parent | 597b4aff7b5d85946d2028ab9498116f53357dbc (diff) |
fs: btrfs: Add single-device read-only BTRFS implementation
This adds the proper implementation for the BTRFS filesystem.
The implementation currently supports only read-only mode and
the filesystem can be only on a single device.
Checksums of data chunks is unimplemented.
Compression is implemented (ZLIB + LZO).
Signed-off-by: Marek Behun <marek.behun@nic.cz>
create mode 100644 fs/btrfs/btrfs.h
create mode 100644 fs/btrfs/chunk-map.c
create mode 100644 fs/btrfs/compression.c
create mode 100644 fs/btrfs/ctree.c
create mode 100644 fs/btrfs/dev.c
create mode 100644 fs/btrfs/dir-item.c
create mode 100644 fs/btrfs/extent-io.c
create mode 100644 fs/btrfs/hash.c
create mode 100644 fs/btrfs/inode.c
create mode 100644 fs/btrfs/root.c
create mode 100644 fs/btrfs/subvolume.c
create mode 100644 fs/btrfs/super.c
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r-- | fs/btrfs/compression.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c new file mode 100644 index 00000000000..a59ff5a8bbf --- /dev/null +++ b/fs/btrfs/compression.c @@ -0,0 +1,134 @@ +/* + * 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 <linux/lzo.h> +#include <u-boot/zlib.h> + +static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen) +{ + u32 tot_len, in_len, res; + size_t out_len; + int ret; + + if (clen < 4) + return -1; + + tot_len = le32_to_cpu(*(u32 *) cbuf); + cbuf += 4; + clen -= 4; + tot_len -= 4; + + if (tot_len == 0 && dlen) + return -1; + if (tot_len < 4) + return -1; + + res = 0; + + while (tot_len > 4) { + in_len = le32_to_cpu(*(u32 *) cbuf); + cbuf += 4; + clen -= 4; + + if (in_len > clen || tot_len < 4 + in_len) + return -1; + + tot_len -= 4 + in_len; + + out_len = dlen; + ret = lzo1x_decompress_safe(cbuf, in_len, dbuf, &out_len); + if (ret != LZO_E_OK) + return -1; + + cbuf += in_len; + clen -= in_len; + dbuf += out_len; + dlen -= out_len; + + res += out_len; + } + + return res; +} + +/* from zutil.h */ +#define PRESET_DICT 0x20 + +static u32 decompress_zlib(const u8 *_cbuf, u32 clen, u8 *dbuf, u32 dlen) +{ + int wbits = MAX_WBITS, ret = -1; + z_stream stream; + u8 *cbuf; + u32 res; + + memset(&stream, 0, sizeof(stream)); + + cbuf = (u8 *) _cbuf; + + stream.total_in = 0; + + stream.next_out = dbuf; + stream.avail_out = dlen; + stream.total_out = 0; + + /* skip adler32 check if deflate and no dictionary */ + if (clen > 2 && !(cbuf[1] & PRESET_DICT) && + ((cbuf[0] & 0x0f) == Z_DEFLATED) && + !(((cbuf[0] << 8) + cbuf[1]) % 31)) { + wbits = -((cbuf[0] >> 4) + 8); + cbuf += 2; + clen -= 2; + } + + if (Z_OK != inflateInit2(&stream, wbits)) + return -1; + + while (stream.total_in < clen) { + stream.next_in = cbuf + stream.total_in; + stream.avail_in = min((u32) (clen - stream.total_in), + (u32) btrfs_info.sb.sectorsize); + + ret = inflate(&stream, Z_NO_FLUSH); + if (ret != Z_OK) + break; + } + + res = stream.total_out; + inflateEnd(&stream); + + if (ret != Z_STREAM_END) + return -1; + + return res; +} + +u32 btrfs_decompress(u8 type, const char *c, u32 clen, char *d, u32 dlen) +{ + u32 res; + const u8 *cbuf; + u8 *dbuf; + + cbuf = (const u8 *) c; + dbuf = (u8 *) d; + + switch (type) { + case BTRFS_COMPRESS_NONE: + res = dlen < clen ? dlen : clen; + memcpy(dbuf, cbuf, res); + return res; + case BTRFS_COMPRESS_ZLIB: + return decompress_zlib(cbuf, clen, dbuf, dlen); + case BTRFS_COMPRESS_LZO: + return decompress_lzo(cbuf, clen, dbuf, dlen); + default: + printf("%s: Unsupported compression in extent: %i\n", __func__, + type); + return -1; + } +} |