diff options
| -rw-r--r-- | fs/btrfs/compression.c | 144 | ||||
| -rw-r--r-- | fs/btrfs/compression.h | 5 | ||||
| -rw-r--r-- | fs/btrfs/lzo.c | 8 | ||||
| -rw-r--r-- | fs/btrfs/zlib.c | 12 | ||||
| -rw-r--r-- | fs/btrfs/zstd.c | 6 |
5 files changed, 76 insertions, 99 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 41ee862470b0..7869ad12bc6e 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -1272,96 +1272,82 @@ void __cold btrfs_exit_compress(void) } /* - * Copy uncompressed data from working buffer to pages. + * Copy decompressed data from working buffer to pages. * - * buf_start is the byte offset we're of the start of our workspace buffer. + * @buf: The decompressed data buffer + * @buf_len: The decompressed data length + * @decompressed: Number of bytes that are already decompressed inside the + * compressed extent + * @cb: The compressed extent descriptor + * @orig_bio: The original bio that the caller wants to read for * - * total_out is the last byte of the buffer + * An easier to understand graph is like below: + * + * |<- orig_bio ->| |<- orig_bio->| + * |<------- full decompressed extent ----->| + * |<----------- @cb range ---->| + * | |<-- @buf_len -->| + * |<--- @decompressed --->| + * + * Note that, @cb can be a subpage of the full decompressed extent, but + * @cb->start always has the same as the orig_file_offset value of the full + * decompressed extent. + * + * When reading compressed extent, we have to read the full compressed extent, + * while @orig_bio may only want part of the range. + * Thus this function will ensure only data covered by @orig_bio will be copied + * to. + * + * Return 0 if we have copied all needed contents for @orig_bio. + * Return >0 if we need continue decompress. */ -int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, - unsigned long total_out, u64 disk_start, - struct bio *bio) +int btrfs_decompress_buf2page(const char *buf, u32 buf_len, + struct compressed_bio *cb, u32 decompressed) { - unsigned long buf_offset; - unsigned long current_buf_start; - unsigned long start_byte; - unsigned long prev_start_byte; - unsigned long working_bytes = total_out - buf_start; - unsigned long bytes; - struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter); - - /* - * start byte is the first byte of the page we're currently - * copying into relative to the start of the compressed data. - */ - start_byte = page_offset(bvec.bv_page) - disk_start; - - /* we haven't yet hit data corresponding to this page */ - if (total_out <= start_byte) - return 1; - - /* - * the start of the data we care about is offset into - * the middle of our working buffer - */ - if (total_out > start_byte && buf_start < start_byte) { - buf_offset = start_byte - buf_start; - working_bytes -= buf_offset; - } else { - buf_offset = 0; - } - current_buf_start = buf_start; - - /* copy bytes from the working buffer into the pages */ - while (working_bytes > 0) { - bytes = min_t(unsigned long, bvec.bv_len, - PAGE_SIZE - (buf_offset % PAGE_SIZE)); - bytes = min(bytes, working_bytes); + struct bio *orig_bio = cb->orig_bio; + /* Offset inside the full decompressed extent */ + u32 cur_offset; + + cur_offset = decompressed; + /* The main loop to do the copy */ + while (cur_offset < decompressed + buf_len) { + struct bio_vec bvec; + size_t copy_len; + u32 copy_start; + /* Offset inside the full decompressed extent */ + u32 bvec_offset; + + bvec = bio_iter_iovec(orig_bio, orig_bio->bi_iter); + /* + * cb->start may underflow, but subtracting that value can still + * give us correct offset inside the full decompressed extent. + */ + bvec_offset = page_offset(bvec.bv_page) + bvec.bv_offset - cb->start; - memcpy_to_page(bvec.bv_page, bvec.bv_offset, buf + buf_offset, - bytes); - flush_dcache_page(bvec.bv_page); + /* Haven't reached the bvec range, exit */ + if (decompressed + buf_len <= bvec_offset) + return 1; - buf_offset += bytes; - working_bytes -= bytes; - current_buf_start += bytes; - - /* check if we need to pick another page */ - bio_advance(bio, bytes); - if (!bio->bi_iter.bi_size) - return 0; - bvec = bio_iter_iovec(bio, bio->bi_iter); - prev_start_byte = start_byte; - start_byte = page_offset(bvec.bv_page) - disk_start; + copy_start = max(cur_offset, bvec_offset); + copy_len = min(bvec_offset + bvec.bv_len, + decompressed + buf_len) - copy_start; + ASSERT(copy_len); /* - * We need to make sure we're only adjusting - * our offset into compression working buffer when - * we're switching pages. Otherwise we can incorrectly - * keep copying when we were actually done. + * Extra range check to ensure we didn't go beyond + * @buf + @buf_len. */ - if (start_byte != prev_start_byte) { - /* - * make sure our new page is covered by this - * working buffer - */ - if (total_out <= start_byte) - return 1; + ASSERT(copy_start - decompressed < buf_len); + memcpy_to_page(bvec.bv_page, bvec.bv_offset, + buf + copy_start - decompressed, copy_len); + flush_dcache_page(bvec.bv_page); + cur_offset += copy_len; - /* - * the next page in the biovec might not be adjacent - * to the last page, but it might still be found - * inside this working buffer. bump our offset pointer - */ - if (total_out > start_byte && - current_buf_start < start_byte) { - buf_offset = start_byte - buf_start; - working_bytes = total_out - start_byte; - current_buf_start = buf_start + buf_offset; - } - } + bio_advance(orig_bio, copy_len); + /* Finished the bio */ + if (!orig_bio->bi_iter.bi_size) + return 0; } - return 1; } diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h index c359f20920d0..399be0b435bf 100644 --- a/fs/btrfs/compression.h +++ b/fs/btrfs/compression.h @@ -86,9 +86,8 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, unsigned long *total_out); int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, unsigned long start_byte, size_t srclen, size_t destlen); -int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, - unsigned long total_out, u64 disk_start, - struct bio *bio); +int btrfs_decompress_buf2page(const char *buf, u32 buf_len, + struct compressed_bio *cb, u32 decompressed); blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start, unsigned int len, u64 disk_start, diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 576a0e6142ad..6cab15e52cec 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -293,8 +293,6 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) unsigned long tot_len; char *buf; struct page **pages_in = cb->compressed_pages; - u64 disk_start = cb->start; - struct bio *orig_bio = cb->orig_bio; data_in = page_address(pages_in[0]); tot_len = read_compress_length(data_in); @@ -391,14 +389,14 @@ cont: buf_start = tot_out; tot_out += out_len; - ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, - tot_out, disk_start, orig_bio); + ret2 = btrfs_decompress_buf2page(workspace->buf, out_len, + cb, buf_start); if (ret2 == 0) break; } done: if (!ret) - zero_fill_bio(orig_bio); + zero_fill_bio(cb->orig_bio); return ret; } diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index 5e18d7ad75a4..8afa90074891 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -275,8 +275,6 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); unsigned long buf_start; struct page **pages_in = cb->compressed_pages; - u64 disk_start = cb->start; - struct bio *orig_bio = cb->orig_bio; data_in = page_address(pages_in[page_in_index]); workspace->strm.next_in = data_in; @@ -314,9 +312,8 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) if (buf_start == total_out) break; - ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, - total_out, disk_start, - orig_bio); + ret2 = btrfs_decompress_buf2page(workspace->buf, + total_out - buf_start, cb, buf_start); if (ret2 == 0) { ret = 0; goto done; @@ -336,8 +333,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) data_in = page_address(pages_in[page_in_index]); workspace->strm.next_in = data_in; tmp = srclen - workspace->strm.total_in; - workspace->strm.avail_in = min(tmp, - PAGE_SIZE); + workspace->strm.avail_in = min(tmp, PAGE_SIZE); } } if (ret != Z_STREAM_END) @@ -347,7 +343,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) done: zlib_inflateEnd(&workspace->strm); if (!ret) - zero_fill_bio(orig_bio); + zero_fill_bio(cb->orig_bio); return ret; } diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c index 200ba08bfae6..56dce9f00988 100644 --- a/fs/btrfs/zstd.c +++ b/fs/btrfs/zstd.c @@ -540,8 +540,6 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) { struct workspace *workspace = list_entry(ws, struct workspace, list); struct page **pages_in = cb->compressed_pages; - u64 disk_start = cb->start; - struct bio *orig_bio = cb->orig_bio; size_t srclen = cb->compressed_len; ZSTD_DStream *stream; int ret = 0; @@ -582,7 +580,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) workspace->out_buf.pos = 0; ret = btrfs_decompress_buf2page(workspace->out_buf.dst, - buf_start, total_out, disk_start, orig_bio); + total_out - buf_start, cb, buf_start); if (ret == 0) break; @@ -607,7 +605,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) } } ret = 0; - zero_fill_bio(orig_bio); + zero_fill_bio(cb->orig_bio); done: return ret; } |