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Commit db7f3436 authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: deal with enomem in the rewind path 



We can get ENOMEM trying to allocate dummy bufs for the rewind operation of the
tree mod log.  Instead of BUG_ON()'ing in this case pass up ENOMEM.  I looked
back through the callers and I'm pretty sure I got everybody who did BUG_ON(ret)
in this path.  Thanks,

Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent ebdad913

fs/btrfs/ctree.c

+14 −2
Original line number Diff line number Diff line
@@ -1211,7 +1211,11 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, 
		BUG_ON(tm->slot != 0);

		eb_rewin = alloc_dummy_extent_buffer(eb->start,

						fs_info->tree_root->nodesize);

		BUG_ON(!eb_rewin);

		if (!eb_rewin) {

			btrfs_tree_read_unlock(eb);

			free_extent_buffer(eb);

			return NULL;

		}

		btrfs_set_header_bytenr(eb_rewin, eb->start);

		btrfs_set_header_backref_rev(eb_rewin,

					     btrfs_header_backref_rev(eb));
@@ -1219,7 +1223,11 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, 
		btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));

	} else {

		eb_rewin = btrfs_clone_extent_buffer(eb);

		BUG_ON(!eb_rewin);

		if (!eb_rewin) {

			btrfs_tree_read_unlock(eb);

			free_extent_buffer(eb);

			return NULL;

		}

	}



	btrfs_tree_read_unlock(eb);
@@ -2772,6 +2780,10 @@ int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key, 
							  BTRFS_READ_LOCK);

			}

			b = tree_mod_log_rewind(root->fs_info, b, time_seq);

			if (!b) {

				ret = -ENOMEM;

				goto done;

			}

			p->locks[level] = BTRFS_READ_LOCK;

			p->nodes[level] = b;

		} else {

fs/btrfs/extent_io.c

+74 −71
Original line number Diff line number Diff line
@@ -4222,6 +4222,76 @@ static void __free_extent_buffer(struct extent_buffer *eb) 
	kmem_cache_free(extent_buffer_cache, eb);

}



static int extent_buffer_under_io(struct extent_buffer *eb)

{

	return (atomic_read(&eb->io_pages) ||

		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||

		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));

}



/*

 * Helper for releasing extent buffer page.

 */

static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,

						unsigned long start_idx)

{

	unsigned long index;

	unsigned long num_pages;

	struct page *page;

	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);



	BUG_ON(extent_buffer_under_io(eb));



	num_pages = num_extent_pages(eb->start, eb->len);

	index = start_idx + num_pages;

	if (start_idx >= index)

		return;



	do {

		index--;

		page = extent_buffer_page(eb, index);

		if (page && mapped) {

			spin_lock(&page->mapping->private_lock);

			/*

			 * We do this since we'll remove the pages after we've

			 * removed the eb from the radix tree, so we could race

			 * and have this page now attached to the new eb.  So

			 * only clear page_private if it's still connected to

			 * this eb.

			 */

			if (PagePrivate(page) &&

			    page->private == (unsigned long)eb) {

				BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));

				BUG_ON(PageDirty(page));

				BUG_ON(PageWriteback(page));

				/*

				 * We need to make sure we haven't be attached

				 * to a new eb.

				 */

				ClearPagePrivate(page);

				set_page_private(page, 0);

				/* One for the page private */

				page_cache_release(page);

			}

			spin_unlock(&page->mapping->private_lock);



		}

		if (page) {

			/* One for when we alloced the page */

			page_cache_release(page);

		}

	} while (index != start_idx);

}



/*

 * Helper for releasing the extent buffer.

 */

static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)

{

	btrfs_release_extent_buffer_page(eb, 0);

	__free_extent_buffer(eb);

}



static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,

						   u64 start,

						   unsigned long len,
@@ -4276,7 +4346,10 @@ struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src) 


	for (i = 0; i < num_pages; i++) {

		p = alloc_page(GFP_ATOMIC);

		BUG_ON(!p);

		if (!p) {

			btrfs_release_extent_buffer(new);

			return NULL;

		}

		attach_extent_buffer_page(new, p);

		WARN_ON(PageDirty(p));

		SetPageUptodate(p);
@@ -4317,76 +4390,6 @@ struct extent_buffer *alloc_dummy_extent_buffer(u64 start, unsigned long len) 
	return NULL;

}



static int extent_buffer_under_io(struct extent_buffer *eb)

{

	return (atomic_read(&eb->io_pages) ||

		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||

		test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));

}



/*

 * Helper for releasing extent buffer page.

 */

static void btrfs_release_extent_buffer_page(struct extent_buffer *eb,

						unsigned long start_idx)

{

	unsigned long index;

	unsigned long num_pages;

	struct page *page;

	int mapped = !test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags);



	BUG_ON(extent_buffer_under_io(eb));



	num_pages = num_extent_pages(eb->start, eb->len);

	index = start_idx + num_pages;

	if (start_idx >= index)

		return;



	do {

		index--;

		page = extent_buffer_page(eb, index);

		if (page && mapped) {

			spin_lock(&page->mapping->private_lock);

			/*

			 * We do this since we'll remove the pages after we've

			 * removed the eb from the radix tree, so we could race

			 * and have this page now attached to the new eb.  So

			 * only clear page_private if it's still connected to

			 * this eb.

			 */

			if (PagePrivate(page) &&

			    page->private == (unsigned long)eb) {

				BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));

				BUG_ON(PageDirty(page));

				BUG_ON(PageWriteback(page));

				/*

				 * We need to make sure we haven't be attached

				 * to a new eb.

				 */

				ClearPagePrivate(page);

				set_page_private(page, 0);

				/* One for the page private */

				page_cache_release(page);

			}

			spin_unlock(&page->mapping->private_lock);



		}

		if (page) {

			/* One for when we alloced the page */

			page_cache_release(page);

		}

	} while (index != start_idx);

}



/*

 * Helper for releasing the extent buffer.

 */

static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)

{

	btrfs_release_extent_buffer_page(eb, 0);

	__free_extent_buffer(eb);

}



static void check_buffer_tree_ref(struct extent_buffer *eb)

{

	int refs;