fs/erofs: add DEFLATE algorithm support

This patch adds DEFLATE compression algorithm support. It's a good choice
to trade off between compression ratios and performance compared to LZ4.
Alternatively, DEFLATE could be used for some specific files since EROFS
supports multiple compression algorithms in one image.

Signed-off-by: Jianan Huang <jnhuang95@gmail.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index ee4e777c5c82127372976ebbca48c27bf7ea68ff..c8463357ca2f3b6f5e3141becfd53abbce998047 100644 (file)
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -19,3 +19,18 @@ config FS_EROFS_ZIP
        help
          Enable fixed-sized output compression for EROFS.
          If you don't want to enable compression feature, say N.
+
+config FS_EROFS_ZIP_DEFLATE
+       bool "EROFS DEFLATE compressed data support"
+       depends on FS_EROFS_ZIP
+       select ZLIB
+       help
+         Saying Y here includes support for reading EROFS file systems
+         containing DEFLATE compressed data.  It gives better compression
+         ratios than the default LZ4 format, while it costs more CPU
+         overhead.
+
+         DEFLATE support is an experimental feature for now and so most
+         file systems will be readable without selecting this option.
+
+         If unsure, say N.

diff --git a/fs/erofs/decompress.c b/fs/erofs/decompress.c
index e04e5c34a8d89210f8ddbb443339e61cbfc06912..ec74816534c6eaf2ddfd5e7d64868158962ce782 100644 (file)
--- a/fs/erofs/decompress.c
+++ b/fs/erofs/decompress.c
@@ -1,6 +1,85 @@
 // SPDX-License-Identifier: GPL-2.0+
 #include "decompress.h"
 
+#if IS_ENABLED(CONFIG_ZLIB)
+#include <u-boot/zlib.h>
+
+/* report a zlib or i/o error */
+static int zerr(int ret)
+{
+       switch (ret) {
+       case Z_STREAM_ERROR:
+               return -EINVAL;
+       case Z_DATA_ERROR:
+               return -EIO;
+       case Z_MEM_ERROR:
+               return -ENOMEM;
+       case Z_ERRNO:
+       default:
+               return -EFAULT;
+       }
+}
+
+static int z_erofs_decompress_deflate(struct z_erofs_decompress_req *rq)
+{
+       u8 *dest = (u8 *)rq->out;
+       u8 *src = (u8 *)rq->in;
+       u8 *buff = NULL;
+       unsigned int inputmargin = 0;
+       z_stream strm;
+       int ret;
+
+       while (!src[inputmargin & (erofs_blksiz() - 1)])
+               if (!(++inputmargin & (erofs_blksiz() - 1)))
+                       break;
+
+       if (inputmargin >= rq->inputsize)
+               return -EFSCORRUPTED;
+
+       if (rq->decodedskip) {
+               buff = malloc(rq->decodedlength);
+               if (!buff)
+                       return -ENOMEM;
+               dest = buff;
+       }
+
+       /* allocate inflate state */
+       strm.zalloc = Z_NULL;
+       strm.zfree = Z_NULL;
+       strm.opaque = Z_NULL;
+       strm.avail_in = 0;
+       strm.next_in = Z_NULL;
+       ret = inflateInit2(&strm, -15);
+       if (ret != Z_OK) {
+               free(buff);
+               return zerr(ret);
+       }
+
+       strm.next_in = src + inputmargin;
+       strm.avail_in = rq->inputsize - inputmargin;
+       strm.next_out = dest;
+       strm.avail_out = rq->decodedlength;
+
+       ret = inflate(&strm, rq->partial_decoding ? Z_SYNC_FLUSH : Z_FINISH);
+       if (ret != Z_STREAM_END || strm.total_out != rq->decodedlength) {
+               if (ret != Z_OK || !rq->partial_decoding) {
+                       ret = zerr(ret);
+                       goto out_inflate_end;
+               }
+       }
+
+       if (rq->decodedskip)
+               memcpy(rq->out, dest + rq->decodedskip,
+                      rq->decodedlength - rq->decodedskip);
+
+out_inflate_end:
+       inflateEnd(&strm);
+       if (buff)
+               free(buff);
+       return ret;
+}
+#endif
+
 #if IS_ENABLED(CONFIG_LZ4)
 #include <u-boot/lz4.h>
 static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
@@ -93,6 +172,10 @@ int z_erofs_decompress(struct z_erofs_decompress_req *rq)
 #if IS_ENABLED(CONFIG_LZ4)
        if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
                return z_erofs_decompress_lz4(rq);
+#endif
+#if IS_ENABLED(CONFIG_ZLIB)
+       if (rq->alg == Z_EROFS_COMPRESSION_DEFLATE)
+               return z_erofs_decompress_deflate(rq);
 #endif
        return -EOPNOTSUPP;
 }

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 158e2c68a1a6d1cde7f80f3f8523683fba16885b..5bac4fe1a1d2b126e7f34fb5276a0be266f65869 100644 (file)
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -304,6 +304,7 @@ enum {
 enum {
        Z_EROFS_COMPRESSION_LZ4         = 0,
        Z_EROFS_COMPRESSION_LZMA        = 1,
+       Z_EROFS_COMPRESSION_DEFLATE     = 2,
        Z_EROFS_COMPRESSION_MAX
 };