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
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
new file mode 100644
index 0000000..a59ff5a
--- /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;
+ }
+}