mm/filemap: add filemap_fdatawrite_range_kick() helper

Works like filemap_fdatawrite_range(), except it's a non-integrity data
writeback and hence only starts writeback on the specified range.  Will
help facilitate generically starting uncached writeback from
generic_write_sync(), as header dependencies preclude doing this inline
from fs.h.

Link: https://lkml.kernel.org/r/20241220154831.1086649-11-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6a838b5479a697e921cabc0cd0c1991a7c6165aa..653b5efa3d3f80e2546e31191b381b23ccc2d4d3 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2878,6 +2878,8 @@ extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,
 extern int __must_check file_check_and_advance_wb_err(struct file *file);
 extern int __must_check file_write_and_wait_range(struct file *file,
                                                loff_t start, loff_t end);
+int filemap_fdatawrite_range_kick(struct address_space *mapping, loff_t start,
+               loff_t end);
 
 static inline int file_write_and_wait(struct file *file)
 {

diff --git a/mm/filemap.c b/mm/filemap.c
index fb17b573ae51684ad2f51ddfea5124a979abd5fa..0aa3861aed45f0b790ffe41b486e4434871e7445 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -440,6 +440,24 @@ int filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
 }
 EXPORT_SYMBOL(filemap_fdatawrite_range);
 
+/**
+ * filemap_fdatawrite_range_kick - start writeback on a range
+ * @mapping:   target address_space
+ * @start:     index to start writeback on
+ * @end:       last (non-inclusive) index for writeback
+ *
+ * This is a non-integrity writeback helper, to start writing back folios
+ * for the indicated range.
+ *
+ * Return: %0 on success, negative error code otherwise.
+ */
+int filemap_fdatawrite_range_kick(struct address_space *mapping, loff_t start,
+                                 loff_t end)
+{
+       return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_NONE);
+}
+EXPORT_SYMBOL_GPL(filemap_fdatawrite_range_kick);
+
 /**
  * filemap_flush - mostly a non-blocking flush
  * @mapping:   target address_space