Hi, In February, David Howells wrote: > nfs_migrate_page() does not wait for FS-Cache to finish with a page, probably > leading to the following bad-page-state: [...] > nfs_migrate_page() calls nfs_fscache_release_page() which doesn't actually wait > - even if __GFP_WAIT is set. The reason that doesn't wait is that > fscache_maybe_release_page() might deadlock the allocator as the work threads > writing to the cache may all end up sleeping on memory allocation. [...] > (1) Make nfs_migrate_page() wait. > > (2) Make fscache_maybe_release_page() honour the __GFP_WAIT flag. > > (3) Set a timeout around the wait. > > (4) Make nfs_migrate_page() return an error if the page is still busy. > > For the moment, I'll select (2) and (4). [...] > --- a/fs/nfs/write.c > +++ b/fs/nfs/write.c > @@ -1701,7 +1701,9 @@ int nfs_migrate_page(struct address_space *mapping, struct page *newpage, > if (PagePrivate(page)) > return -EBUSY; > > - nfs_fscache_release_page(page, GFP_KERNEL); > + ret = -EBUSY; > + if (!nfs_fscache_release_page(page, GFP_KERNEL)) > + goto out; > > return migrate_page(mapping, newpage, page, mode); > } Small thing, but it looks like this was forward-ported incorrectly. Was this ever tested with CONFIG_MIGRATION enabled? Hope that helps, Jonathan -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
