...and reorganize the loop for better clarity.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/ceph/addr.c | 141 ++++++++++++++++++++++---------------------------
1 file changed, 62 insertions(+), 79 deletions(-)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index a04eaf75480b..f4df04769761 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1252,6 +1252,8 @@ static int context_is_writeable_or_written(struct inode *inode,
* @inode: inode associated with page
* @page: page being dirtied
*
+ * We are only allowed to write into/dirty the page if the page is
+ * clean, or already dirty within the same snap context.
* Returns NULL on success, negative error code on error, and a snapc ref that should be
* waited on otherwise.
*/
@@ -1308,104 +1310,85 @@ ceph_find_incompatible(struct inode *inode, struct page *page)
/*
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
- *
- * called with page locked.
- * return success with page locked,
- * or any failure (incl -EAGAIN) with page unlocked.
*/
-static int ceph_update_writeable_page(struct file *file,
- loff_t pos, unsigned len,
- struct page *page)
+static int ceph_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
{
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_snap_context *snapc;
+ struct page *page = NULL;
+ pgoff_t index = pos >> PAGE_SHIFT;
loff_t page_off = pos & PAGE_MASK;
int pos_in_page = pos & ~PAGE_MASK;
int end_in_page = pos_in_page + len;
loff_t i_size;
int r;
+refind:
+ /* get a page */
+ page = grab_cache_page_write_begin(mapping, index, 0);
+ if (!page)
+ return -ENOMEM;
-retry_locked:
- snapc = ceph_find_incompatible(inode, page);
- if (snapc) {
- if (IS_ERR(snapc)) {
- r = PTR_ERR(snapc);
- goto fail_unlock;
+ dout("write_begin file %p inode %p page %p %d~%d\n", file,
+ inode, page, (int)pos, (int)len);
+
+ for (;;) {
+ snapc = ceph_find_incompatible(inode, page);
+ if (snapc) {
+ if (IS_ERR(snapc)) {
+ r = PTR_ERR(snapc);
+ break;
+ }
+ unlock_page(page);
+ ceph_queue_writeback(inode);
+ r = wait_event_killable(ci->i_cap_wq,
+ context_is_writeable_or_written(inode, snapc));
+ ceph_put_snap_context(snapc);
+ put_page(page);
+ goto refind;
}
- unlock_page(page);
- ceph_queue_writeback(inode);
- r = wait_event_killable(ci->i_cap_wq,
- context_is_writeable_or_written(inode, snapc));
- ceph_put_snap_context(snapc);
- return -EAGAIN;
- }
- if (PageUptodate(page)) {
- dout(" page %p already uptodate\n", page);
- return 0;
- }
+ if (PageUptodate(page)) {
+ dout(" page %p already uptodate\n", page);
+ break;
+ }
- /* full page? */
- if (pos_in_page == 0 && len == PAGE_SIZE)
- return 0;
+ /* full page? */
+ if (pos_in_page == 0 && len == PAGE_SIZE)
+ break;
- /* past end of file? */
- i_size = i_size_read(inode);
-
- if (page_off >= i_size ||
- (pos_in_page == 0 && (pos+len) >= i_size &&
- end_in_page - pos_in_page != PAGE_SIZE)) {
- dout(" zeroing %p 0 - %d and %d - %d\n",
- page, pos_in_page, end_in_page, (int)PAGE_SIZE);
- zero_user_segments(page,
- 0, pos_in_page,
- end_in_page, PAGE_SIZE);
- return 0;
- }
+ /* past end of file? */
+ i_size = i_size_read(inode);
+ if (page_off >= i_size ||
+ (pos_in_page == 0 && (pos+len) >= i_size &&
+ end_in_page - pos_in_page != PAGE_SIZE)) {
+ dout(" zeroing %p 0 - %d and %d - %d\n",
+ page, pos_in_page, end_in_page, (int)PAGE_SIZE);
+ zero_user_segments(page,
+ 0, pos_in_page,
+ end_in_page, PAGE_SIZE);
+ break;
+ }
- /* we need to read it. */
- r = ceph_do_readpage(file, page);
- if (r < 0) {
- if (r == -EINPROGRESS)
- return -EAGAIN;
- goto fail_unlock;
+ /* we need to read it. */
+ r = ceph_do_readpage(file, page);
+ if (r) {
+ if (r == -EINPROGRESS)
+ continue;
+ break;
+ }
}
- goto retry_locked;
-fail_unlock:
- unlock_page(page);
- return r;
-}
-/*
- * We are only allowed to write into/dirty the page if the page is
- * clean, or already dirty within the same snap context.
- */
-static int ceph_write_begin(struct file *file, struct address_space *mapping,
- loff_t pos, unsigned len, unsigned flags,
- struct page **pagep, void **fsdata)
-{
- struct inode *inode = file_inode(file);
- struct page *page;
- pgoff_t index = pos >> PAGE_SHIFT;
- int r;
-
- do {
- /* get a page */
- page = grab_cache_page_write_begin(mapping, index, 0);
- if (!page)
- return -ENOMEM;
-
- dout("write_begin file %p inode %p page %p %d~%d\n", file,
- inode, page, (int)pos, (int)len);
-
- r = ceph_update_writeable_page(file, pos, len, page);
- if (r < 0)
+ if (r < 0) {
+ if (page) {
+ unlock_page(page);
put_page(page);
- else
- *pagep = page;
- } while (r == -EAGAIN);
-
+ }
+ } else {
+ *pagep = page;
+ }
return r;
}
--
2.26.2
