From 8f246b7c0a1be0882374f2ff831a61f0dbe77678 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 29 Jul 2024 12:23:11 +0100 Subject: [PATCH] netfs: Cancel dirty folios that have no storage destination Kafs wants to be able to cache the contents of directories (and symlinks), but whilst these are downloaded from the server with the FS.FetchData RPC op and similar, the same as for regular files, they can't be updated by FS.StoreData, but rather have special operations (FS.MakeDir, etc.). Now, rather than redownloading a directory's content after each change made to that directory, kafs modifies the local blob. This blob can be saved out to the cache, and since it's using netfslib, kafs just marks the folios dirty and lets ->writepages() on the directory take care of it, as for an regular file. This is fine as long as there's a cache as although the upload stream is disabled, there's a cache stream to drive the procedure. But if the cache goes away in the meantime, suddenly there's no way do any writes and the code gets confused, complains "R=%x: No submit" to dmesg and leaves the dirty folio hanging. Fix this by just cancelling the store of the folio if neither stream is active. (If there's no cache at the time of dirtying, we should just not mark the folio dirty). Signed-off-by: David Howells cc: Jeff Layton cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20240814203850.2240469-23-dhowells@redhat.com/ # v2 Signed-off-by: Christian Brauner --- fs/netfs/write_issue.c | 6 +++++- include/trace/events/netfs.h | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index f7d59f0bb8c2..04e66d587f77 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -400,13 +400,17 @@ static int netfs_write_folio(struct netfs_io_request *wreq, folio_unlock(folio); if (fgroup == NETFS_FOLIO_COPY_TO_CACHE) { - if (!fscache_resources_valid(&wreq->cache_resources)) { + if (!cache->avail) { trace_netfs_folio(folio, netfs_folio_trace_cancel_copy); netfs_issue_write(wreq, upload); netfs_folio_written_back(folio); return 0; } trace_netfs_folio(folio, netfs_folio_trace_store_copy); + } else if (!upload->avail && !cache->avail) { + trace_netfs_folio(folio, netfs_folio_trace_cancel_store); + netfs_folio_written_back(folio); + return 0; } else if (!upload->construct) { trace_netfs_folio(folio, netfs_folio_trace_store); } else { diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 7b26463cb98f..76bd42a96815 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -153,6 +153,7 @@ EM(netfs_streaming_cont_filled_page, "mod-streamw-f+") \ EM(netfs_folio_trace_abandon, "abandon") \ EM(netfs_folio_trace_cancel_copy, "cancel-copy") \ + EM(netfs_folio_trace_cancel_store, "cancel-store") \ EM(netfs_folio_trace_clear, "clear") \ EM(netfs_folio_trace_clear_cc, "clear-cc") \ EM(netfs_folio_trace_clear_g, "clear-g") \