btrfs: replace many BUG_ONs with proper error handling

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / btrfs / extent_io.c

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ffa7cc3..4c3ce7a 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1244,7 +1244,7 @@ static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 
        while (index <= end_index) {
                page = find_get_page(tree->mapping, index);
-               BUG_ON(!page);
+               BUG_ON(!page); /* Pages should be in the extent_io_tree */
                set_page_writeback(page);
                page_cache_release(page);
                index++;
@@ -1523,7 +1523,7 @@ again:
                        goto out_failed;
                }
        }
-       BUG_ON(ret);
+       BUG_ON(ret); /* Only valid values are 0 and -EAGAIN */
 
        /* step three, lock the state bits for the whole range */
        lock_extent_bits(tree, delalloc_start, delalloc_end, 0, &cached_state);
@@ -2200,7 +2200,6 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
                /* Writeback already completed */
                if (ret == 0)
                        return 1;
-               BUG_ON(ret < 0);
        }
 
        if (!uptodate) {
@@ -2353,7 +2352,6 @@ error_handled:
                                if (ret == 0)
                                        goto error_handled;
                        }
-                       BUG_ON(ret < 0);
                }
 
                if (uptodate) {
@@ -2405,6 +2403,10 @@ btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
        return bio;
 }
 
+/*
+ * Since writes are async, they will only return -ENOMEM.
+ * Reads can return the full range of I/O error conditions.
+ */
 static int __must_check submit_one_bio(int rw, struct bio *bio,
                                       int mirror_num, unsigned long bio_flags)
 {
@@ -2477,7 +2479,8 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
                    bio_add_page(bio, page, page_size, offset) < page_size) {
                        ret = submit_one_bio(rw, bio, mirror_num,
                                             prev_bio_flags);
-                       BUG_ON(ret < 0);
+                       if (ret < 0)
+                               return ret;
                        bio = NULL;
                } else {
                        return 0;
@@ -2498,10 +2501,8 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
 
        if (bio_ret)
                *bio_ret = bio;
-       else {
+       else
                ret = submit_one_bio(rw, bio, mirror_num, bio_flags);
-               BUG_ON(ret < 0);
-       }
 
        return ret;
 }
@@ -2525,6 +2526,7 @@ static void set_page_extent_head(struct page *page, unsigned long len)
  * basic readpage implementation.  Locked extent state structs are inserted
  * into the tree that are removed when the IO is done (by the end_io
  * handlers)
+ * XXX JDM: This needs looking at to ensure proper page locking
  */
 static int __extent_read_full_page(struct extent_io_tree *tree,
                                   struct page *page,
@@ -2687,6 +2689,7 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
                                         end_bio_extent_readpage, mirror_num,
                                         *bio_flags,
                                         this_bio_flag);
+                       BUG_ON(ret == -ENOMEM);
                        nr++;
                        *bio_flags = this_bio_flag;
                }
@@ -2713,10 +2716,8 @@ int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
 
        ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
                                      &bio_flags);
-       if (bio) {
+       if (bio)
                ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
-               BUG_ON(ret < 0);
-       }
        return ret;
 }
 
@@ -2830,7 +2831,11 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                                                       delalloc_end,
                                                       &page_started,
                                                       &nr_written);
-                       BUG_ON(ret);
+                       /* File system has been set read-only */
+                       if (ret) {
+                               SetPageError(page);
+                               goto done;
+                       }
                        /*
                         * delalloc_end is already one less than the total
                         * length, so we don't subtract one from
@@ -3141,7 +3146,7 @@ static void flush_epd_write_bio(struct extent_page_data *epd)
                        rw = WRITE_SYNC;
 
                ret = submit_one_bio(rw, epd->bio, 0, 0);
-               BUG_ON(ret < 0);
+               BUG_ON(ret < 0); /* -ENOMEM */
                epd->bio = NULL;
        }
 }
@@ -3257,10 +3262,8 @@ int extent_readpages(struct extent_io_tree *tree,
                page_cache_release(page);
        }
        BUG_ON(!list_empty(pages));
-       if (bio) {
-               int ret = submit_one_bio(READ, bio, 0, bio_flags);
-               BUG_ON(ret < 0);
-       }
+       if (bio)
+               return submit_one_bio(READ, bio, 0, bio_flags);
        return 0;
 }
 
@@ -4090,7 +4093,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 
        if (bio) {
                err = submit_one_bio(READ, bio, mirror_num, bio_flags);
-               BUG_ON(err < 0);
+               if (err)
+                       return err;
        }
 
        if (ret || wait != WAIT_COMPLETE)