[PATCH v2 06/53] netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space

From: David Howells
Date: Fri Oct 22 2021 - 15:01:05 EST


Pass a flag to ->prepare_write() to indicate if there's definitely no
space allocated in the cache yet (for instance if we've already checked as
we were asked to do a read).

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: linux-cachefs@xxxxxxxxxx
---

fs/cachefiles_old/io.c | 3 ++-
fs/netfs/read_helper.c | 2 +-
include/linux/netfs.h | 3 ++-
3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/cachefiles_old/io.c b/fs/cachefiles_old/io.c
index 5ead97de4bb7..eab8641de994 100644
--- a/fs/cachefiles_old/io.c
+++ b/fs/cachefiles_old/io.c
@@ -341,7 +341,8 @@ static enum netfs_read_source cachefiles_prepare_read(struct netfs_read_subreque
* Prepare for a write to occur.
*/
static int cachefiles_prepare_write(struct netfs_cache_resources *cres,
- loff_t *_start, size_t *_len, loff_t i_size)
+ loff_t *_start, size_t *_len, loff_t i_size,
+ bool no_space_allocated_yet)
{
loff_t start = *_start;
size_t len = *_len, down;
diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c
index dfc60c79a9f3..80f8e334371d 100644
--- a/fs/netfs/read_helper.c
+++ b/fs/netfs/read_helper.c
@@ -323,7 +323,7 @@ static void netfs_rreq_do_write_to_cache(struct netfs_read_request *rreq)
}

ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len,
- rreq->i_size);
+ rreq->i_size, true);
if (ret < 0) {
trace_netfs_failure(rreq, subreq, ret, netfs_fail_prepare_write);
trace_netfs_sreq(subreq, netfs_sreq_trace_write_skip);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 014fb502fd91..99137486d351 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -220,7 +220,8 @@ struct netfs_cache_ops {
* actually do.
*/
int (*prepare_write)(struct netfs_cache_resources *cres,
- loff_t *_start, size_t *_len, loff_t i_size);
+ loff_t *_start, size_t *_len, loff_t i_size,
+ bool no_space_allocated_yet);

/* Prepare a write operation for the fallback fscache API, working out
* whether we can cache a page or not.