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-rw-r--r--fs/btrfs/lzo.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index cc9b450399df..a178f5ebea78 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -280,6 +280,7 @@ static int lzo_decompress_biovec(struct list_head *ws,
unsigned long tot_out;
unsigned long tot_len;
char *buf;
+ bool may_late_unmap, need_unmap;
data_in = kmap(pages_in[0]);
tot_len = read_compress_length(data_in);
@@ -300,11 +301,13 @@ static int lzo_decompress_biovec(struct list_head *ws,
tot_in += in_len;
working_bytes = in_len;
+ may_late_unmap = need_unmap = false;
/* fast path: avoid using the working buffer */
if (in_page_bytes_left >= in_len) {
buf = data_in + in_offset;
bytes = in_len;
+ may_late_unmap = true;
goto cont;
}
@@ -329,14 +332,17 @@ cont:
if (working_bytes == 0 && tot_in >= tot_len)
break;
- kunmap(pages_in[page_in_index]);
- page_in_index++;
- if (page_in_index >= total_pages_in) {
+ if (page_in_index + 1 >= total_pages_in) {
ret = -1;
- data_in = NULL;
goto done;
}
- data_in = kmap(pages_in[page_in_index]);
+
+ if (may_late_unmap)
+ need_unmap = true;
+ else
+ kunmap(pages_in[page_in_index]);
+
+ data_in = kmap(pages_in[++page_in_index]);
in_page_bytes_left = PAGE_CACHE_SIZE;
in_offset = 0;
@@ -346,6 +352,8 @@ cont:
out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
&out_len);
+ if (need_unmap)
+ kunmap(pages_in[page_in_index - 1]);
if (ret != LZO_E_OK) {
printk(KERN_WARNING "btrfs decompress failed\n");
ret = -1;
@@ -363,8 +371,7 @@ cont:
break;
}
done:
- if (data_in)
- kunmap(pages_in[page_in_index]);
+ kunmap(pages_in[page_in_index]);
return ret;
}