diff options
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 4cf55ef54193..3d0ca48d20c8 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1993,6 +1993,15 @@ static int ext4_writepage(struct page *page, else len = PAGE_SIZE; + /* Should never happen but for bugs in other kernel subsystems */ + if (!page_has_buffers(page)) { + ext4_warning_inode(inode, + "page %lu does not have buffers attached", page->index); + ClearPageDirty(page); + unlock_page(page); + return 0; + } + page_bufs = page_buffers(page); /* * We cannot do block allocation or other extent handling in this @@ -2594,6 +2603,22 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd) wait_on_page_writeback(page); BUG_ON(PageWriteback(page)); + /* + * Should never happen but for buggy code in + * other subsystems that call + * set_page_dirty() without properly warning + * the file system first. See [1] for more + * information. + * + * [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz + */ + if (!page_has_buffers(page)) { + ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", page->index); + ClearPageDirty(page); + unlock_page(page); + continue; + } + if (mpd->map.m_len == 0) mpd->first_page = page->index; mpd->next_page = page->index + 1; @@ -3548,10 +3573,11 @@ const struct iomap_ops ext4_iomap_report_ops = { }; /* - * Pages can be marked dirty completely asynchronously from ext4's journalling - * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do - * much here because ->set_page_dirty is called under VFS locks. The page is - * not necessarily locked. + * Whenever the page is being dirtied, corresponding buffers should already be + * attached to the transaction (we take care of this in ext4_page_mkwrite() and + * ext4_write_begin()). However we cannot move buffers to dirty transaction + * lists here because ->set_page_dirty is called under VFS locks and the page + * is not necessarily locked. * * We cannot just dirty the page and leave attached buffers clean, because the * buffers' dirty state is "definitive". We cannot just set the buffers dirty @@ -3562,6 +3588,7 @@ const struct iomap_ops ext4_iomap_report_ops = { */ static int ext4_journalled_set_page_dirty(struct page *page) { + WARN_ON_ONCE(!page_has_buffers(page)); SetPageChecked(page); return __set_page_dirty_nobuffers(page); } |