diff options
| -rw-r--r-- | fs/ext4/inode.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ff913d0cd4b6..118eb674038a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3669,24 +3669,26 @@ const struct iomap_ops ext4_iomap_report_ops = { }; /* - * Whenever the folio 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 ->dirty_folio is called under VFS locks and the folio - * is not necessarily locked. - * - * We cannot just dirty the folio and leave attached buffers clean, because the - * buffers' dirty state is "definitive". We cannot just set the buffers dirty - * or jbddirty because all the journalling code will explode. - * - * So what we do is to mark the folio "pending dirty" and next time writepage - * is called, propagate that into the buffers appropriately. + * For data=journal mode, folio should be marked dirty only when it was + * writeably mapped. When that happens, it was already attached to the + * transaction and marked as jbddirty (we take care of this in + * ext4_page_mkwrite()). On transaction commit, we writeprotect page mappings + * so we should have nothing to do here, except for the case when someone + * had the page pinned and dirtied the page through this pin (e.g. by doing + * direct IO to it). In that case we'd need to attach buffers here to the + * transaction but we cannot due to lock ordering. We cannot just dirty the + * folio and leave attached buffers clean, because the buffers' dirty state is + * "definitive". We cannot just set the buffers dirty or jbddirty because all + * the journalling code will explode. So what we do is to mark the folio + * "pending dirty" and next time ext4_writepages() is called, attach buffers + * to the transaction appropriately. */ static bool ext4_journalled_dirty_folio(struct address_space *mapping, struct folio *folio) { WARN_ON_ONCE(!folio_buffers(folio)); - folio_set_checked(folio); + if (folio_maybe_dma_pinned(folio)) + folio_set_checked(folio); return filemap_dirty_folio(mapping, folio); } |