For lz4 worst compress case, caller should allocate buffer with size
of LZ4_compressBound(inputsize) for target compressed data storing.
However lz4 supports partial data compression, so we can get rid of
output buffer size limitation now, then we can avoid 2 * 4KB size
intermediate buffer allocation when log_cluster_size is 2, and avoid
unnecessary compressing work of compressor if we can not save at
least 4KB space.
Suggested-by: Daeho Jeong <daehoje...@google.com>
Signed-off-by: Chao Yu <yuch...@huawei.com>
---
fs/f2fs/compress.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 5e4947250262..23825f559bcf 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -228,7 +228,12 @@ static int lz4_init_compress_ctx(struct compress_ctx *cc)
if (!cc->private)
return -ENOMEM;
- cc->clen = LZ4_compressBound(PAGE_SIZE << cc->log_cluster_size);
+ /*
+ * we do not change cc->clen to LZ4_compressBound(inputsize) to
+ * adapt worst compress case, because lz4 algorithm supports partial
+ * compression.
+ */
+ cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE;
return 0;
}
@@ -244,11 +249,9 @@ static int lz4_compress_pages(struct compress_ctx *cc)
len = LZ4_compress_default(cc->rbuf, cc->cbuf->cdata, cc->rlen,
cc->clen, cc->private);
- if (!len) {
- printk_ratelimited("%sF2FS-fs (%s): lz4 compress failed\n",
- KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id);
- return -EIO;
- }
+ if (!len)
+ return -EAGAIN;
+
cc->clen = len;
return 0;
}
--
2.18.0.rc1
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