CIFS: Find and reopen a file before get MTU credits in writepages

Reorder finding and reopening a writable handle file and getting
MTU credits in writepages because we may be stuck on low credits
otherwise.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 18 insertions, 6 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index eaf5acba7f6b..4de7af04e732 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2096,15 +2096,16 @@ wdata_send_pages(struct TCP_Server_Info *server, struct cifs_writedata *wdata,
         if (rc)
                 goto send_pages_out;
 
-        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");
+                cifs_dbg(VFS, "No writable handle in writepages\n");
                 rc = -EBADF;
         } else {
                 wdata->pid = wdata->cfile->pid;
-                rc = server->ops->async_writev(wdata, cifs_writedata_release);
+                if (wdata->cfile->invalidHandle)
+                        rc = -EAGAIN;
+                else
+                        rc = server->ops->async_writev(wdata,
+                                                       cifs_writedata_release);
         }
 
 send_pages_out:
@@ -2117,11 +2118,13 @@ send_pages_out:
 static int cifs_writepages(struct address_space *mapping,
                            struct writeback_control *wbc)
 {
-        struct cifs_sb_info *cifs_sb = CIFS_SB(mapping->host->i_sb);
+        struct inode *inode = mapping->host;
+        struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
         struct TCP_Server_Info *server;
         bool done = false, scanned = false, range_whole = false;
         pgoff_t end, index;
         struct cifs_writedata *wdata;
+        struct cifsFileInfo *cfile = NULL;
         int rc = 0;
         int saved_rc = 0;
         unsigned int xid;
@@ -2152,6 +2155,11 @@ retry:
                 struct cifs_credits credits_on_stack;
                 struct cifs_credits *credits = &credits_on_stack;
 
+                if (cfile)
+                        cifsFileInfo_put(cfile);
+
+                cfile = find_writable_file(CIFS_I(inode), false);
+
                 rc = server->ops->wait_mtu_credits(server, cifs_sb->wsize,
                                                    &wsize, credits);
                 if (rc != 0) {
@@ -2187,6 +2195,8 @@ retry:
                 }
 
                 wdata->credits = credits_on_stack;
+                wdata->cfile = cfile;
+                cfile = NULL;
 
                 rc = wdata_send_pages(server, wdata, nr_pages, mapping, wbc);
 
@@ -2244,6 +2254,8 @@ retry:
         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
                 mapping->writeback_index = index;
 
+        if (cfile)
+                cifsFileInfo_put(cfile);
         free_xid(xid);
         return rc;
 }