/**
* nfs_create_request - Create an NFS read/write request.
* @ctx: open context to use
* @inode: inode to which the request is attached
* @page: page to write
* @offset: starting offset within the page for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *
nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
struct nfs_lock_context *l_ctx;
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req == NULL)
return ERR_PTR(-ENOMEM);
/* get lock context early so we can deal with alloc failures */
l_ctx = nfs_get_lock_context(ctx);
if (IS_ERR(l_ctx)) {
nfs_page_free(req);
return ERR_CAST(l_ctx);
}
req->wb_lock_context = l_ctx;
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
req->wb_index = page_file_index(page);
page_cache_get(page);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
req->wb_context = get_nfs_open_context(ctx);
kref_init(&req->wb_kref);
return req;
}
/**
* nfs_release_request - Release the count on an NFS read/write request
* @req: request to release
*
* Note: Should never be called with the spinlock held!
*/
static void nfs_free_request(struct kref *kref)
{
struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
/* Release struct file and open context */
nfs_clear_request(req);
nfs_page_free(req);
}
/**
* nfs_release_request - Release the count on an NFS read/write request
* @req: request to release
*
* Note: Should never be called with the spinlock held!
*/
static void nfs_free_request(struct kref *kref)
{
struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
/* Release struct file or cached credential */
nfs_clear_request(req);
put_nfs_open_context(req->wb_context);
nfs_page_free(req);
}
/**
* nfs_release_request - Release the count on an NFS read/write request
* @req: request to release
*
* Note: Should never be called with the spinlock held!
*/
void nfs_free_request(struct nfs_page *req)
{
WARN_ON_ONCE(req->wb_this_page != req);
/* extra debug: make sure no sync bits are still set */
WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
/* Release struct file and open context */
nfs_clear_request(req);
nfs_page_free(req);
}
/**
* nfs_release_request - Release the count on an NFS read/write request
* @req: request to release
*
* Note: Should never be called with the spinlock held!
*/
void
nfs_release_request(struct nfs_page *req)
{
if (!atomic_dec_and_test(&req->wb_count))
return;
#ifdef NFS_PARANOIA
BUG_ON (!list_empty(&req->wb_list));
BUG_ON (NFS_WBACK_BUSY(req));
#endif
/* Release struct file or cached credential */
nfs_clear_request(req);
put_nfs_open_context(req->wb_context);
nfs_page_free(req);
}
/**
* nfs_create_request - Create an NFS read/write request.
* @file: file descriptor to use
* @inode: inode to which the request is attached
* @page: page to write
* @offset: starting offset within the page for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *
nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req == NULL)
return ERR_PTR(-ENOMEM);
/* get lock context early so we can deal with alloc failures */
req->wb_lock_context = nfs_get_lock_context(ctx);
if (req->wb_lock_context == NULL) {
nfs_page_free(req);
return ERR_PTR(-ENOMEM);
}
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
atomic_set(&req->wb_complete, 0);
req->wb_index = page->index;
page_cache_get(page);
BUG_ON(PagePrivate(page));
BUG_ON(!PageLocked(page));
BUG_ON(page->mapping->host != inode);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
req->wb_context = get_nfs_open_context(ctx);
kref_init(&req->wb_kref);
return req;
}
