From 9b038d004ce95551cb35381c49fe896c5bc11ffe Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 21 May 2024 14:37:43 +0100 Subject: [PATCH] netfs: Fix io_uring based write-through This can be triggered by mounting a cifs filesystem with a cache=strict mount option and then, using the fsx program from xfstests, doing: ltp/fsx -A -d -N 1000 -S 11463 -P /tmp /cifs-mount/foo \ --replay-ops=gen112-fsxops Where gen112-fsxops holds: fallocate 0x6be7 0x8fc5 0x377d3 copy_range 0x9c71 0x77e8 0x2edaf 0x377d3 write 0x2776d 0x8f65 0x377d3 The problem is that netfs_io_request::len is being used for two purposes and ends up getting set to the amount of data we transferred, not the amount of data the caller asked to be transferred (for various reasons, such as mmap'd writes, we might end up rounding out the data written to the server to include the entire folio at each end). Fix this by keeping the amount we were asked to write in ->len and using ->submitted to track what we issued ops for. Then, when we come to calling ->ki_complete(), ->len is the right size. This also required netfs_cleanup_dio_write() to change since we're no longer advancing wreq->len. Use wreq->transferred instead as we might have done a short read. With this, the generic/112 xfstest passes if cifs is forced to put all non-DIO opens into write-through mode. Fixes: 288ace2f57c9 ("netfs: New writeback implementation") Signed-off-by: David Howells Link: https://lore.kernel.org/r/295086.1716298663@warthog.procyon.org.uk cc: Jeff Layton cc: Steve French cc: Enzo Matsumiya cc: netfs@lists.linux.dev cc: v9fs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner --- fs/netfs/direct_write.c | 2 +- fs/netfs/write_collect.c | 7 ++++--- fs/netfs/write_issue.c | 2 +- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c index 608ba6416919..28163516bf03 100644 --- a/fs/netfs/direct_write.c +++ b/fs/netfs/direct_write.c @@ -12,7 +12,7 @@ static void netfs_cleanup_dio_write(struct netfs_io_request *wreq) { struct inode *inode = wreq->inode; - unsigned long long end = wreq->start + wreq->len; + unsigned long long end = wreq->start + wreq->transferred; if (!wreq->error && i_size_read(inode) < end) { diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c index 60112e4b2c5e..426cf87aaf2e 100644 --- a/fs/netfs/write_collect.c +++ b/fs/netfs/write_collect.c @@ -510,7 +510,7 @@ reassess_streams: * stream has a gap that can be jumped. */ if (notes & SOME_EMPTY) { - unsigned long long jump_to = wreq->start + wreq->len; + unsigned long long jump_to = wreq->start + READ_ONCE(wreq->submitted); for (s = 0; s < NR_IO_STREAMS; s++) { stream = &wreq->io_streams[s]; @@ -690,10 +690,11 @@ void netfs_write_collection_worker(struct work_struct *work) wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS); if (wreq->iocb) { - wreq->iocb->ki_pos += wreq->transferred; + size_t written = min(wreq->transferred, wreq->len); + wreq->iocb->ki_pos += written; if (wreq->iocb->ki_complete) wreq->iocb->ki_complete( - wreq->iocb, wreq->error ? wreq->error : wreq->transferred); + wreq->iocb, wreq->error ? wreq->error : written); wreq->iocb = VFS_PTR_POISON; } diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index e190043bc0da..86dad7e4202b 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -254,7 +254,7 @@ static void netfs_issue_write(struct netfs_io_request *wreq, stream->construct = NULL; if (subreq->start + subreq->len > wreq->start + wreq->submitted) - wreq->len = wreq->submitted = subreq->start + subreq->len - wreq->start; + WRITE_ONCE(wreq->submitted, subreq->start + subreq->len - wreq->start); netfs_do_issue_write(stream, subreq); }