Merge branches 'pm-core', 'pm-qos', 'pm-domains' and 'pm-opp'

[linux.git] / fs / btrfs / compression.c

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7f390849343b3e42b9399c2ac58b948c87944902..c4444d6f439f676cee59a20322d0f88fcb3cc4a3 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1024,6 +1024,7 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
        unsigned long buf_offset;
        unsigned long current_buf_start;
        unsigned long start_byte;
+       unsigned long prev_start_byte;
        unsigned long working_bytes = total_out - buf_start;
        unsigned long bytes;
        char *kaddr;
@@ -1071,26 +1072,34 @@ int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
                if (!bio->bi_iter.bi_size)
                        return 0;
                bvec = bio_iter_iovec(bio, bio->bi_iter);
-
+               prev_start_byte = start_byte;
                start_byte = page_offset(bvec.bv_page) - disk_start;
 
                /*
-                * make sure our new page is covered by this
-                * working buffer
+                * We need to make sure we're only adjusting
+                * our offset into compression working buffer when
+                * we're switching pages.  Otherwise we can incorrectly
+                * keep copying when we were actually done.
                 */
-               if (total_out <= start_byte)
-                       return 1;
+               if (start_byte != prev_start_byte) {
+                       /*
+                        * make sure our new page is covered by this
+                        * working buffer
+                        */
+                       if (total_out <= start_byte)
+                               return 1;
 
-               /*
-                * the next page in the biovec might not be adjacent
-                * to the last page, but it might still be found
-                * inside this working buffer. bump our offset pointer
-                */
-               if (total_out > start_byte &&
-                   current_buf_start < start_byte) {
-                       buf_offset = start_byte - buf_start;
-                       working_bytes = total_out - start_byte;
-                       current_buf_start = buf_start + buf_offset;
+                       /*
+                        * the next page in the biovec might not be adjacent
+                        * to the last page, but it might still be found
+                        * inside this working buffer. bump our offset pointer
+                        */
+                       if (total_out > start_byte &&
+                           current_buf_start < start_byte) {
+                               buf_offset = start_byte - buf_start;
+                               working_bytes = total_out - start_byte;
+                               current_buf_start = buf_start + buf_offset;
+                       }
                }
        }