return 0;
}
+/*
+ * Write data into @out_folio and queue it into @out_bio.
+ *
+ * Return 0 if everything is fine and @total_out will be increased.
+ * Return <0 for error.
+ *
+ * The @out_folio can be NULL after a full folio is queued.
+ * Thus the caller should check and allocate a new folio when needed.
+ */
+static int write_and_queue_folio(struct bio *out_bio, struct folio **out_folio,
+ u32 *total_out, u32 write_len)
+{
+ const u32 fsize = folio_size(*out_folio);
+ const u32 foffset = offset_in_folio(*out_folio, *total_out);
+
+ ASSERT(out_folio && *out_folio);
+ /* Should not cross folio boundary. */
+ ASSERT(foffset + write_len <= fsize);
+
+ /* We can not use bio_add_folio_nofail() which doesn't do any merge. */
+ if (!bio_add_folio(out_bio, *out_folio, write_len, foffset)) {
+ /*
+ * We have allocated a bio that havs BTRFS_MAX_COMPRESSED_PAGES
+ * vecs, and all ranges inside the same folio should have been
+ * merged. If bio_add_folio() still failed, that means we have
+ * reached the bvec limits.
+ *
+ * This should only happen at the beginning of a folio, and
+ * caller is responsible for releasing the folio, since it's
+ * not yet queued into the bio.
+ */
+ ASSERT(IS_ALIGNED(*total_out, fsize));
+ return -E2BIG;
+ }
+
+ *total_out += write_len;
+ /*
+ * The full folio has been filled and queued, reset @out_folio to NULL,
+ * so that error handling is fully handled by the bio.
+ */
+ if (IS_ALIGNED(*total_out, fsize))
+ *out_folio = NULL;
+ return 0;
+}
+
+/*
+ * Copy compressed data to bio.
+ *
+ * @out_bio: The bio that will contain all the compressed data.
+ * @compressed_data: The compressed data of this segment.
+ * @compressed_size: The size of the compressed data.
+ * @out_folio: The current output folio, will be updated if a new
+ * folio is allocated.
+ * @total_out: The total bytes of current output.
+ * @max_out: The maximum size of the compressed data.
+ *
+ * Will do:
+ *
+ * - Write a segment header into the destination
+ * - Copy the compressed buffer into the destination
+ * - Make sure we have enough space in the last sector to fit a segment header
+ * If not, we will pad at most (LZO_LEN (4)) - 1 bytes of zeros.
+ * - If a full folio is filled, it will be queued into @out_bio, and @out_folio
+ * will be updated.
+ *
+ * Will allocate new pages when needed.
+ */
+static int copy_compressed_data_to_bio(struct btrfs_fs_info *fs_info,
+ struct bio *out_bio,
+ const char *compressed_data,
+ size_t compressed_size,
+ struct folio **out_folio,
+ u32 *total_out, u32 max_out)
+{
+ const u32 sectorsize = fs_info->sectorsize;
+ const u32 sectorsize_bits = fs_info->sectorsize_bits;
+ const u32 fsize = btrfs_min_folio_size(fs_info);
+ const u32 old_size = out_bio->bi_iter.bi_size;
+ u32 copy_start;
+ u32 sector_bytes_left;
+ char *kaddr;
+ int ret;
+
+ ASSERT(out_folio);
+
+ /* There should be at least a lzo header queued. */
+ ASSERT(old_size);
+ ASSERT(old_size == *total_out);
+
+ /*
+ * We never allow a segment header crossing sector boundary, previous
+ * run should ensure we have enough space left inside the sector.
+ */
+ ASSERT((old_size >> sectorsize_bits) == (old_size + LZO_LEN - 1) >> sectorsize_bits);
+
+ if (!*out_folio) {
+ *out_folio = btrfs_alloc_compr_folio(fs_info);
+ if (!*out_folio)
+ return -ENOMEM;
+ }
+
+ /* Write the segment header first. */
+ kaddr = kmap_local_folio(*out_folio, offset_in_folio(*out_folio, *total_out));
+ write_compress_length(kaddr, compressed_size);
+ kunmap_local(kaddr);
+ ret = write_and_queue_folio(out_bio, out_folio, total_out, LZO_LEN);
+ if (ret < 0)
+ return ret;
+
+ copy_start = *total_out;
+
+ /* Copy compressed data. */
+ while (*total_out - copy_start < compressed_size) {
+ u32 copy_len = min_t(u32, sectorsize - *total_out % sectorsize,
+ copy_start + compressed_size - *total_out);
+ u32 foffset = *total_out & (fsize - 1);
+
+ /* With the range copied, we're larger than the original range. */
+ if (((*total_out + copy_len) >> sectorsize_bits) >=
+ max_out >> sectorsize_bits)
+ return -E2BIG;
+
+ if (!*out_folio) {
+ *out_folio = btrfs_alloc_compr_folio(fs_info);
+ if (!*out_folio)
+ return -ENOMEM;
+ }
+
+ kaddr = kmap_local_folio(*out_folio, foffset);
+ memcpy(kaddr, compressed_data + *total_out - copy_start, copy_len);
+ kunmap_local(kaddr);
+ ret = write_and_queue_folio(out_bio, out_folio, total_out, copy_len);
+ if (ret < 0)
+ return ret;
+ }
+
+ /*
+ * Check if we can fit the next segment header into the remaining space
+ * of the sector.
+ */
+ sector_bytes_left = round_up(*total_out, sectorsize) - *total_out;
+ if (sector_bytes_left >= LZO_LEN || sector_bytes_left == 0)
+ return 0;
+
+ ASSERT(*out_folio);
+
+ /* The remaining size is not enough, pad it with zeros */
+ folio_zero_range(*out_folio, offset_in_folio(*out_folio, *total_out), sector_bytes_left);
+ return write_and_queue_folio(out_bio, out_folio, total_out, sector_bytes_left);
+}
+
int lzo_compress_folios(struct list_head *ws, struct btrfs_inode *inode,
u64 start, struct folio **folios, unsigned long *out_folios,
unsigned long *total_in, unsigned long *total_out)
return ret;
}
+int lzo_compress_bio(struct list_head *ws, struct compressed_bio *cb)
+{
+ struct btrfs_inode *inode = cb->bbio.inode;
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct workspace *workspace = list_entry(ws, struct workspace, list);
+ struct bio *bio = &cb->bbio.bio;
+ const u64 start = cb->start;
+ const u32 len = cb->len;
+ const u32 sectorsize = fs_info->sectorsize;
+ const u32 min_folio_size = btrfs_min_folio_size(fs_info);
+ struct address_space *mapping = inode->vfs_inode.i_mapping;
+ struct folio *folio_in = NULL;
+ struct folio *folio_out = NULL;
+ char *sizes_ptr;
+ int ret = 0;
+ /* Points to the file offset of input data. */
+ u64 cur_in = start;
+ /* Points to the current output byte. */
+ u32 total_out = 0;
+
+ ASSERT(bio->bi_iter.bi_size == 0);
+ ASSERT(len);
+
+ folio_out = btrfs_alloc_compr_folio(fs_info);
+ if (!folio_out)
+ return -ENOMEM;
+
+ /* Queue a segment header first. */
+ ret = write_and_queue_folio(bio, &folio_out, &total_out, LZO_LEN);
+ /* The first header should not fail. */
+ ASSERT(ret == 0);
+
+ while (cur_in < start + len) {
+ char *data_in;
+ const u32 sectorsize_mask = sectorsize - 1;
+ u32 sector_off = (cur_in - start) & sectorsize_mask;
+ u32 in_len;
+ size_t out_len;
+
+ /* Get the input page first. */
+ if (!folio_in) {
+ ret = btrfs_compress_filemap_get_folio(mapping, cur_in, &folio_in);
+ if (ret < 0)
+ goto out;
+ }
+
+ /* Compress at most one sector of data each time. */
+ in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);
+ ASSERT(in_len);
+ data_in = kmap_local_folio(folio_in, offset_in_folio(folio_in, cur_in));
+ ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf, &out_len,
+ workspace->mem);
+ kunmap_local(data_in);
+ if (unlikely(ret < 0)) {
+ /* lzo1x_1_compress never fails. */
+ ret = -EIO;
+ goto out;
+ }
+
+ ret = copy_compressed_data_to_bio(fs_info, bio, workspace->cbuf, out_len,
+ &folio_out, &total_out, len);
+ if (ret < 0)
+ goto out;
+
+ cur_in += in_len;
+
+ /*
+ * Check if we're making it bigger after two sectors. And if
+ * it is so, give up.
+ */
+ if (cur_in - start > sectorsize * 2 && cur_in - start < total_out) {
+ ret = -E2BIG;
+ goto out;
+ }
+
+ /* Check if we have reached input folio boundary. */
+ if (IS_ALIGNED(cur_in, min_folio_size)) {
+ folio_put(folio_in);
+ folio_in = NULL;
+ }
+ }
+ /*
+ * The last folio is already queued. Bio is responsible for freeing
+ * those folios now.
+ */
+ folio_out = NULL;
+
+ /* Store the size of all chunks of compressed data */
+ sizes_ptr = kmap_local_folio(bio_first_folio_all(bio), 0);
+ write_compress_length(sizes_ptr, total_out);
+ kunmap_local(sizes_ptr);
+out:
+ /*
+ * We can only free the folio that has no part queued into the bio.
+ *
+ * As any folio that is already queued into bio will be released by
+ * the endio function of bio.
+ */
+ if (folio_out && IS_ALIGNED(total_out, min_folio_size)) {
+ btrfs_free_compr_folio(folio_out);
+ folio_out = NULL;
+ }
+ if (folio_in)
+ folio_put(folio_in);
+ return ret;
+}
+
static struct folio *get_current_folio(struct compressed_bio *cb, struct folio_iter *fi,
u32 *cur_folio_index, u32 cur_in)
{
projects / thirdparty / kernel / linux.git / commitdiff
