linux/include/trace
David Howells 8f246b7c0a
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 <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
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 <brauner@kernel.org>
History 2024-09-12 12:20:41 +02:00
..
events netfs: Cancel dirty folios that have no storage destination 2024-09-12 12:20:41 +02:00
misc NFS/knfsd: Remove the invalid NFS error 'NFSERR_OPNOTSUPP' 2024-05-06 12:47:24 -04:00
stages tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
bpf_probe.h bpf: pass whole link instead of prog when triggering raw tracepoint 2024-03-19 23:05:33 -07:00
define_custom_trace.h tracing: Add TRACE_CUSTOM_EVENT() macro 2022-03-11 11:49:24 -05:00
define_trace.h tracepoint: Optimize using static_call() 2020-09-01 09:58:06 +02:00
perf.h perf/tracing: Use stage6 of tracing to not duplicate macros 2023-01-25 10:31:24 -05:00
syscall.h tracepoints: Migrate to use SYSCALL_WORK flag 2020-11-16 21:53:15 +01:00
trace_custom_events.h tracing: Rename the staging files for trace_events 2022-04-02 08:40:04 -04:00
trace_events.h tracing: Rename the staging files for trace_events 2022-04-02 08:40:04 -04:00