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-rw-r--r--fs/btrfs/compression.c39
1 files changed, 24 insertions, 15 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7f390849343b..c4444d6f439f 100644
--- 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;
+ }
}
}