Commit e0ace6ca authored by David Howells's avatar David Howells
Browse files

netfs, cachefiles: Pass upper bound length to allow expansion 



Make netfslib pass the maximum length to the ->prepare_write() op to tell
the cache how much it can expand the length of a write to.  This allows a
write to the server at the end of a file to be limited to a few bytes
whilst writing an entire block to the cache (something required by direct
I/O).

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
parent 80645bd4

fs/cachefiles/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -233,7 +233,7 @@ extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres, 
				       enum fscache_want_state want_state);

extern int __cachefiles_prepare_write(struct cachefiles_object *object,

				      struct file *file,

				      loff_t *_start, size_t *_len,

				      loff_t *_start, size_t *_len, size_t upper_len,

				      bool no_space_allocated_yet);

extern int __cachefiles_write(struct cachefiles_object *object,

			      struct file *file,

fs/cachefiles/io.c

+6 −4
Original line number Diff line number Diff line
@@ -518,7 +518,7 @@ cachefiles_prepare_ondemand_read(struct netfs_cache_resources *cres, 
 */

int __cachefiles_prepare_write(struct cachefiles_object *object,

			       struct file *file,

			       loff_t *_start, size_t *_len,

			       loff_t *_start, size_t *_len, size_t upper_len,

			       bool no_space_allocated_yet)

{

	struct cachefiles_cache *cache = object->volume->cache;
@@ -530,6 +530,8 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 
	down = start - round_down(start, PAGE_SIZE);

	*_start = start - down;

	*_len = round_up(down + len, PAGE_SIZE);

	if (down < start || *_len > upper_len)

		return -ENOBUFS;



	/* We need to work out whether there's sufficient disk space to perform

	 * the write - but we can skip that check if we have space already
@@ -592,8 +594,8 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 
}



static int cachefiles_prepare_write(struct netfs_cache_resources *cres,

				    loff_t *_start, size_t *_len, loff_t i_size,

				    bool no_space_allocated_yet)

				    loff_t *_start, size_t *_len, size_t upper_len,

				    loff_t i_size, bool no_space_allocated_yet)

{

	struct cachefiles_object *object = cachefiles_cres_object(cres);

	struct cachefiles_cache *cache = object->volume->cache;
@@ -609,7 +611,7 @@ static int cachefiles_prepare_write(struct netfs_cache_resources *cres, 


	cachefiles_begin_secure(cache, &saved_cred);

	ret = __cachefiles_prepare_write(object, cachefiles_cres_file(cres),

					 _start, _len,

					 _start, _len, upper_len,

					 no_space_allocated_yet);

	cachefiles_end_secure(cache, saved_cred);

	return ret;

fs/cachefiles/ondemand.c

+1 −1
Original line number Diff line number Diff line
@@ -52,7 +52,7 @@ static ssize_t cachefiles_ondemand_fd_write_iter(struct kiocb *kiocb, 
		return -ENOBUFS;



	cachefiles_begin_secure(cache, &saved_cred);

	ret = __cachefiles_prepare_write(object, file, &pos, &len, true);

	ret = __cachefiles_prepare_write(object, file, &pos, &len, len, true);

	cachefiles_end_secure(cache, saved_cred);

	if (ret < 0)

		return ret;

fs/netfs/fscache_io.c

+1 −1
Original line number Diff line number Diff line
@@ -237,7 +237,7 @@ void __fscache_write_to_cache(struct fscache_cookie *cookie, 
				    fscache_access_io_write) < 0)

		goto abandon_free;



	ret = cres->ops->prepare_write(cres, &start, &len, i_size, false);

	ret = cres->ops->prepare_write(cres, &start, &len, len, i_size, false);

	if (ret < 0)

		goto abandon_end;

fs/netfs/io.c

+1 −1
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq) 
		}



		ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len,

					       rreq->i_size, true);

					       subreq->len, 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);