btrfs: return errno instead of -1 from compression

The compression layer seems to have been built to return -1 and have
callers make up errors that make sense.  This isn't great because there
are different errors that originate down in the compression layer.

Let's return real negative errnos from the compression layer so that
callers can pass on the error without having to guess what happened.
ENOMEM for allocation failure, E2BIG when compression exceeds the
uncompressed input, and EIO for everything else.

This helps a future path return errors from btrfs_decompress().

Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index b47f669..dfad851 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -143,7 +143,7 @@ static int lzo_compress_pages(struct list_head *ws,
 		if (ret != LZO_E_OK) {
 			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;
 				}
 
@@ -208,7 +208,7 @@ static int lzo_compress_pages(struct list_head *ws,
 
 		/* we're making it bigger, give up */
 		if (tot_in > 8192 && tot_in < tot_out) {
-			ret = -1;
+			ret = -E2BIG;
 			goto out;
 		}
 
@@ -335,7 +335,7 @@ cont:
 					break;
 
 				if (page_in_index + 1 >= total_pages_in) {
-					ret = -1;
+					ret = -EIO;
 					goto done;
 				}
 
@@ -358,7 +358,7 @@ cont:
 			kunmap(pages_in[page_in_index - 1]);
 		if (ret != LZO_E_OK) {
 			printk(KERN_WARNING "BTRFS: decompress failed\n");
-			ret = -1;
+			ret = -EIO;
 			break;
 		}
 
@@ -402,12 +402,12 @@ static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 	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;
+		ret = -EIO;
 		goto out;
 	}
 
 	if (out_len < start_byte) {
-		ret = -1;
+		ret = -EIO;
 		goto out;
 	}