CIFS: Fix wsize usage in writepages

If a server change maximum buffer size for write (wsize) requests
on reconnect we can fail on repeating with a big size buffer on
-EAGAIN error in writepages. Fix this by checking wsize all the
time before repeating request in writepages.

Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 14 insertions, 11 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0064d38fdb76..ff4a9c3fe421 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2009,19 +2009,17 @@ wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
                         (loff_t)PAGE_CACHE_SIZE);
         wdata->bytes = ((nr_pages - 1) * PAGE_CACHE_SIZE) + wdata->tailsz;
 
-        do {
-                if (wdata->cfile != NULL)
-                        cifsFileInfo_put(wdata->cfile);
-                wdata->cfile = find_writable_file(CIFS_I(mapping->host), false);
-                if (!wdata->cfile) {
-                        cifs_dbg(VFS, "No writable handles for inode\n");
-                        rc = -EBADF;
-                        break;
-                }
+        if (wdata->cfile != NULL)
+                cifsFileInfo_put(wdata->cfile);
+        wdata->cfile = find_writable_file(CIFS_I(mapping->host), false);
+        if (!wdata->cfile) {
+                cifs_dbg(VFS, "No writable handles for inode\n");
+                rc = -EBADF;
+        } else {
                 wdata->pid = wdata->cfile->pid;
                 server = tlink_tcon(wdata->cfile->tlink)->ses->server;
                 rc = server->ops->async_writev(wdata, cifs_writedata_release);
-        } while (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN);
+        }
 
         for (i = 0; i < nr_pages; ++i)
                 unlock_page(wdata->pages[i]);
@@ -2058,7 +2056,7 @@ static int cifs_writepages(struct address_space *mapping,
 retry:
         while (!done && index <= end) {
                 unsigned int i, nr_pages, found_pages;
-                pgoff_t next = 0, tofind;
+                pgoff_t next = 0, tofind, saved_index = index;
 
                 tofind = min((cifs_sb->wsize / PAGE_CACHE_SIZE) - 1,
                                 end - index) + 1;
@@ -2102,6 +2100,11 @@ retry:
                 }
                 kref_put(&wdata->refcount, cifs_writedata_release);
 
+                if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN) {
+                        index = saved_index;
+                        continue;
+                }
+
                 wbc->nr_to_write -= nr_pages;
                 if (wbc->nr_to_write <= 0)
                         done = true;