Hi Jens, Today's linux-next merge of the block tree got a conflict in fs/fs-writeback.c between commit 74ba19abbeae ("vfs: add support for a lazytime mount option") from the ext4 tree and commit 9c6ac78eb352 ("writeback: fix a subtle race condition in I_DIRTY clearing") from the block tree. I fixed it up (maybe, please check - see below) and can carry the fix as necessary (no action is required). -- Cheers, Stephen Rothwell sfr@xxxxxxxxxxxxxxxx diff --cc fs/fs-writeback.c index cab2d6d74828,2d609a5fbfea..000000000000 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@@ -480,12 -479,28 +480,28 @@@ __writeback_single_inode(struct inode * * write_inode() */ spin_lock(&inode->i_lock); - /* Clear I_DIRTY_PAGES if we've written out all dirty pages */ - if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) - inode->i_state &= ~I_DIRTY_PAGES; + dirty = inode->i_state & I_DIRTY; - inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_TIME); - inode->i_state &= ~I_DIRTY; ++ inode->i_state &= ~(I_DIRTY | I_DIRTY_TIME); + + /* + * Paired with smp_mb() in __mark_inode_dirty(). This allows + * __mark_inode_dirty() to test i_state without grabbing i_lock - + * either they see the I_DIRTY bits cleared or we see the dirtied + * inode. + * + * I_DIRTY_PAGES is always cleared together above even if @mapping + * still has dirty pages. The flag is reinstated after smp_mb() if + * necessary. This guarantees that either __mark_inode_dirty() + * sees clear I_DIRTY_PAGES or we see PAGECACHE_TAG_DIRTY. + */ + smp_mb(); + + if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) + inode->i_state |= I_DIRTY_PAGES; + spin_unlock(&inode->i_lock); + /* Don't write the inode if only I_DIRTY_PAGES was set */ if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { int err = write_inode(inode, wbc);
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