Btrfs: don't ignore compressed bio write errors

Our compressed bio write end callback was essentially ignoring the error
parameter. When a write error happens, it must pass a value of 0 to the
inode's write_page_end_io_hook callback, SetPageError on the respective
pages and set AS_EIO in the inode's mapping flags, so that a call to
filemap_fdatawait_range() / filemap_fdatawait() can find out that errors
happened (we surely don't want silent failures on fsync for example).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index d3220d31d3cb..1bf411bc28fd 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -224,16 +224,19 @@ out:
  * Clear the writeback bits on all of the file
  * pages for a compressed write
  */
-static noinline void end_compressed_writeback(struct inode *inode, u64 start,
-                                              unsigned long ram_size)
+static noinline void end_compressed_writeback(struct inode *inode,
+                                              const struct compressed_bio *cb)
 {
-        unsigned long index = start >> PAGE_CACHE_SHIFT;
-        unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT;
+        unsigned long index = cb->start >> PAGE_CACHE_SHIFT;
+        unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_CACHE_SHIFT;
         struct page *pages[16];
         unsigned long nr_pages = end_index - index + 1;
         int i;
         int ret;
 
+        if (cb->errors)
+                mapping_set_error(inode->i_mapping, -EIO);
+
         while (nr_pages > 0) {
                 ret = find_get_pages_contig(inode->i_mapping, index,
                                      min_t(unsigned long,
@@ -244,6 +247,8 @@ static noinline void end_compressed_writeback(struct inode *inode, u64 start,
                         continue;
                 }
                 for (i = 0; i < ret; i++) {
+                        if (cb->errors)
+                                SetPageError(pages[i]);
                         end_page_writeback(pages[i]);
                         page_cache_release(pages[i]);
                 }
@@ -287,10 +292,11 @@ static void end_compressed_bio_write(struct bio *bio, int err)
         tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
                                          cb->start,
                                          cb->start + cb->len - 1,
-                                         NULL, 1);
+                                         NULL,
+                                         err ? 0 : 1);
         cb->compressed_pages[0]->mapping = NULL;
 
-        end_compressed_writeback(inode, cb->start, cb->len);
+        end_compressed_writeback(inode, cb);
         /* note, our inode could be gone now */
 
         /*