6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: David Howells dhowells@redhat.com
[ Upstream commit 86ad1a58f6a9453f49e06ef957a40a8dac00a13f ]
When netfslib wants to copy some data that has just been read on behalf of nfs, it creates a new write request and calls nfs_netfs_init_request() to initialise it, but with a NULL file pointer. This causes nfs_file_open_context() to oops - however, we don't actually need the nfs context as we're only going to write to the cache.
Fix this by just returning if we aren't given a file pointer and emit a warning if the request was for something other than copy-to-cache.
Further, fix nfs_netfs_free_request() so that it doesn't try to free the context if the pointer is NULL.
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Reported-by: Max Kellermann max.kellermann@ionos.com Closes: https://lore.kernel.org/r/CAKPOu+9DyMbKLhyJb7aMLDTb=Fh0T8Teb9sjuf_pze+XWT1Va... Signed-off-by: David Howells dhowells@redhat.com Link: https://lore.kernel.org/r/20241213135013.2964079-5-dhowells@redhat.com cc: Trond Myklebust trondmy@kernel.org cc: Anna Schumaker anna@kernel.org cc: Dave Wysochanski dwysocha@redhat.com cc: Jeff Layton jlayton@kernel.org cc: linux-nfs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/fscache.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index 810269ee0a50..d49e4ce27999 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -263,6 +263,12 @@ int nfs_netfs_readahead(struct readahead_control *ractl) static atomic_t nfs_netfs_debug_id; static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *file) { + if (!file) { + if (WARN_ON_ONCE(rreq->origin != NETFS_PGPRIV2_COPY_TO_CACHE)) + return -EIO; + return 0; + } + rreq->netfs_priv = get_nfs_open_context(nfs_file_open_context(file)); rreq->debug_id = atomic_inc_return(&nfs_netfs_debug_id); /* [DEPRECATED] Use PG_private_2 to mark folio being written to the cache. */ @@ -274,7 +280,8 @@ static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file *fi
static void nfs_netfs_free_request(struct netfs_io_request *rreq) { - put_nfs_open_context(rreq->netfs_priv); + if (rreq->netfs_priv) + put_nfs_open_context(rreq->netfs_priv); }
static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest *sreq)