[RFC PATCH 5/9] cifs: Add some helper functions

From: David Howells
Date: Fri Oct 28 2022 - 11:58:42 EST


Add some helper functions to manipulate the folio marks by iterating
through a list of folios held in an xarray rather than using a page list.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steve French <sfrench@xxxxxxxxx>
cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
cc: linux-cifs@xxxxxxxxxxxxxxx
---

fs/cifs/cifsfs.h | 3 ++
fs/cifs/file.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 96 insertions(+)

diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 388b745a978e..e3ecf1406d1b 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -110,6 +110,9 @@ extern int cifs_file_strict_mmap(struct file * , struct vm_area_struct *);
extern const struct file_operations cifs_dir_ops;
extern int cifs_dir_open(struct inode *inode, struct file *file);
extern int cifs_readdir(struct file *file, struct dir_context *ctx);
+extern void cifs_pages_written_back(struct inode *inode, loff_t start, unsigned int len);
+extern void cifs_pages_write_failed(struct inode *inode, loff_t start, unsigned int len);
+extern void cifs_pages_write_redirty(struct inode *inode, loff_t start, unsigned int len);

/* Functions related to dir entries */
extern const struct dentry_operations cifs_dentry_ops;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5b3b308e115c..0780d9bfb61d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -36,6 +36,99 @@
#include "cifs_ioctl.h"
#include "cached_dir.h"

+/*
+ * Completion of write to server.
+ */
+void cifs_pages_written_back(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ folio_detach_private(folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
+/*
+ * Failure of write to server.
+ */
+void cifs_pages_write_failed(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ folio_set_error(folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
+/*
+ * Redirty pages after a temporary failure.
+ */
+void cifs_pages_write_redirty(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ filemap_dirty_folio(folio->mapping, folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
/*
* Mark as invalid, all open files on tree connections since they
* were closed when session to server was lost.