[PATCH v4 02/21] cachefiles: export write routine

Jeffle Xu
2022-03-07T12:33:35Z

Extract and export the generic routine of writing data to cache files.

This is used by the following patch implementing on-demand read mode.
Since it will be called inside cachefiles, make the interface generic
and unrelated to netfs_cache_resources.

It is worth nothing that, ki->inval_counter is not initialized after
this cleanup. It shall not make any visible difference, since
inval_counter is no longer used in the write completion routine, i.e.
cachefiles_write_complete().

Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
fs/cachefiles/internal.h | 10 +++++++
fs/cachefiles/io.c | 61 +++++++++++++++++++++++-----------------
2 files changed, 45 insertions(+), 26 deletions(-)

diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index c793d33b0224..e80673d0ab97 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -201,6 +201,16 @@ extern void cachefiles_put_object(struct cachefiles_object *object,
*/
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,
+ bool no_space_allocated_yet);
+extern int __cachefiles_write(struct cachefiles_object *object,
+ struct file *file,
+ loff_t start_pos,
+ struct iov_iter *iter,
+ netfs_io_terminated_t term_func,
+ void *term_func_priv);

/*
* key.c
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index 753986ea1583..8dbc1eb254a3 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -278,36 +278,33 @@ static void cachefiles_write_complete(struct kiocb *iocb, long ret)
/*
* Initiate a write to the cache.
*/
-static int cachefiles_write(struct netfs_cache_resources *cres,
- loff_t start_pos,
- struct iov_iter *iter,
- netfs_io_terminated_t term_func,
- void *term_func_priv)
+int __cachefiles_write(struct cachefiles_object *object,
+ struct file *file,
+ loff_t start_pos,
+ struct iov_iter *iter,
+ netfs_io_terminated_t term_func,
+ void *term_func_priv)
{
- struct cachefiles_object *object;
struct cachefiles_cache *cache;
struct cachefiles_kiocb *ki;
struct inode *inode;
- struct file *file;
unsigned int old_nofs;
- ssize_t ret = -ENOBUFS;
+ ssize_t ret;
size_t len = iov_iter_count(iter);

- if (!fscache_wait_for_operation(cres, FSCACHE_WANT_WRITE))
- goto presubmission_error;
fscache_count_write();
- object = cachefiles_cres_object(cres);
cache = object->volume->cache;
- file = cachefiles_cres_file(cres);

_enter("%pD,%li,%llx,%zx/%llx",
file, file_inode(file)->i_ino, start_pos, len,
i_size_read(file_inode(file)));

- ret = -ENOMEM;
ki = kzalloc(sizeof(struct cachefiles_kiocb), GFP_KERNEL);
- if (!ki)
- goto presubmission_error;
+ if (!ki) {
+ if (term_func)
+ term_func(term_func_priv, -ENOMEM, false);
+ return -ENOMEM;
+ }

refcount_set(&ki->ki_refcnt, 2);
ki->iocb.ki_filp = file;
@@ -316,7 +313,6 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
ki->iocb.ki_hint = ki_hint_validate(file_write_hint(file));
ki->iocb.ki_ioprio = get_current_ioprio();
ki->object = object;
- ki->inval_counter = cres->inval_counter;
ki->start = start_pos;
ki->len = len;
ki->term_func = term_func;
@@ -371,11 +367,24 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
cachefiles_put_kiocb(ki);
_leave(" = %zd", ret);
return ret;
+}

-presubmission_error:
- if (term_func)
- term_func(term_func_priv, ret, false);
- return ret;
+static int cachefiles_write(struct netfs_cache_resources *cres,
+ loff_t start_pos,
+ struct iov_iter *iter,
+ netfs_io_terminated_t term_func,
+ void *term_func_priv)
+{
+ if (!fscache_wait_for_operation(cres, FSCACHE_WANT_WRITE)) {
+ if (term_func)
+ term_func(term_func_priv, -ENOBUFS, false);
+ return -ENOBUFS;
+ }
+
+ return __cachefiles_write(cachefiles_cres_object(cres),
+ cachefiles_cres_file(cres),
+ start_pos, iter,
+ term_func, term_func_priv);
}

/*
@@ -486,13 +495,12 @@ 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,
- bool no_space_allocated_yet)
+int __cachefiles_prepare_write(struct cachefiles_object *object,
+ struct file *file,
+ loff_t *_start, size_t *_len,
+ bool no_space_allocated_yet)
{
- struct cachefiles_object *object = cachefiles_cres_object(cres);
struct cachefiles_cache *cache = object->volume->cache;
- struct file *file = cachefiles_cres_file(cres);
loff_t start = *_start, pos;
size_t len = *_len, down;
int ret;
@@ -579,7 +587,8 @@ static int cachefiles_prepare_write(struct netfs_cache_resources *cres,
}

cachefiles_begin_secure(cache, &saved_cred);
- ret = __cachefiles_prepare_write(cres, _start, _len, i_size,
+ ret = __cachefiles_prepare_write(object, cachefiles_cres_file(cres),
+ _start, _len,
no_space_allocated_yet);
cachefiles_end_secure(cache, saved_cred);
return ret;
--
2.27.0