cachefiles: extract write routine

Extract the generic routine of writing data to cache files, and make it
generally available.

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

It is worth noting 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>
Acked-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20220425122143.56815-2-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index c793d33..e80673d 100644 (file)
--- 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 9dc81e7..50a14e8 100644 (file)
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -277,36 +277,33 @@ 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;
@@ -314,7 +311,6 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
        ki->iocb.ki_flags       = IOCB_DIRECT | IOCB_WRITE;
        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;
@@ -369,11 +365,24 @@ in_progress:
        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);
 }
 
 /*
@@ -484,13 +493,12 @@ out_no_object:
 /*
  * 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;
@@ -577,7 +585,8 @@ 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;