1 files changed, 30 insertions, 21 deletions

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index cc9b450399d..dfad8514f0d 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -31,8 +31,8 @@
 
 struct workspace {
 	void *mem;
-	void *buf;	/* where compressed data goes */
-	void *cbuf;	/* where decompressed data goes */
+	void *buf;	/* where decompressed data goes */
+	void *cbuf;	/* where compressed data goes */
 	struct list_head list;
 };
 
@@ -141,9 +141,9 @@ static int lzo_compress_pages(struct list_head *ws,
 		ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
 				       &out_len, workspace->mem);
 		if (ret != LZO_E_OK) {
-			printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
+			printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
 			       ret);
-			ret = -1;
+			ret = -EIO;
 			goto out;
 		}
 
@@ -189,7 +189,7 @@ static int lzo_compress_pages(struct list_head *ws,
 				kunmap(out_page);
 				if (nr_pages == nr_dest_pages) {
 					out_page = NULL;
-					ret = -1;
+					ret = -E2BIG;
 					goto out;
 				}
 
@@ -207,8 +207,10 @@ static int lzo_compress_pages(struct list_head *ws,
 		}
 
 		/* we're making it bigger, give up */
-		if (tot_in > 8192 && tot_in < tot_out)
+		if (tot_in > 8192 && tot_in < tot_out) {
+			ret = -E2BIG;
 			goto out;
+		}
 
 		/* we're all done */
 		if (tot_in >= len)
@@ -280,6 +282,7 @@ 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 +303,13 @@ 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 +334,17 @@ 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) {
-					ret = -1;
-					data_in = NULL;
+				if (page_in_index + 1 >= total_pages_in) {
+					ret = -EIO;
 					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;
@@ -346,9 +354,11 @@ 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;
+			printk(KERN_WARNING "BTRFS: decompress failed\n");
+			ret = -EIO;
 			break;
 		}
 
@@ -363,8 +373,7 @@ cont:
 			break;
 	}
 done:
-	if (data_in)
-		kunmap(pages_in[page_in_index]);
+	kunmap(pages_in[page_in_index]);
 	return ret;
 }
 
@@ -392,21 +401,21 @@ static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 	out_len = PAGE_CACHE_SIZE;
 	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
 	if (ret != LZO_E_OK) {
-		printk(KERN_WARNING "btrfs decompress failed!\n");
-		ret = -1;
+		printk(KERN_WARNING "BTRFS: decompress failed!\n");
+		ret = -EIO;
 		goto out;
 	}
 
 	if (out_len < start_byte) {
-		ret = -1;
+		ret = -EIO;
 		goto out;
 	}
 
 	bytes = min_t(unsigned long, destlen, out_len - start_byte);
 
-	kaddr = kmap_atomic(dest_page, KM_USER0);
+	kaddr = kmap_atomic(dest_page);
 	memcpy(kaddr, workspace->buf + start_byte, bytes);
-	kunmap_atomic(kaddr, KM_USER0);
+	kunmap_atomic(kaddr);
 out:
 	return ret;
 }