Merge patch series "fs: refactor write_begin/write_end and add ext4 IOCB_DONTCACHE support"

陈涛涛 Taotao Chen <chentaotao@didiglobal.com> says:

This patch series refactors the address_space_operations write_begin()
and write_end() callbacks to take const struct kiocb * as their first
argument, allowing IOCB flags such as IOCB_DONTCACHE to propagate to the
filesystem's buffered I/O path.

Ext4 is updated to implement handling of the IOCB_DONTCACHE flag and
advertises support via the FOP_DONTCACHE file operation flag.

Additionally, the i915 driver's shmem write paths are updated to bypass
the legacy write_begin/write_end interface in favor of directly
calling write_iter() with a constructed synchronous kiocb. Another i915
change replaces a manual write loop with kernel_write() during GEM shmem
object creation.

Tested with ext4 and i915 GEM workloads.

* patches from https://lore.kernel.org/20250716093559.217344-1-chentaotao@didiglobal.com:
  ext4: support uncached buffered I/O
  mm/pagemap: add write_begin_get_folio() helper function
  fs: change write_begin/write_end interface to take struct kiocb *
  drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter
  drm/i915: Use kernel_write() in shmem object create

Link: https://lore.kernel.org/20250716093559.217344-1-chentaotao@didiglobal.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 13 insertions, 13 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 565fe88773c2..ead4dc85debd 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2297,9 +2297,9 @@ int block_write_end(loff_t pos, unsigned len, unsigned copied,
 }
 EXPORT_SYMBOL(block_write_end);
 
-int generic_write_end(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len, unsigned copied,
-			struct folio *folio, void *fsdata)
+int generic_write_end(const struct kiocb *iocb, struct address_space *mapping,
+		      loff_t pos, unsigned len, unsigned copied,
+		      struct folio *folio, void *fsdata)
 {
 	struct inode *inode = mapping->host;
 	loff_t old_size = inode->i_size;
@@ -2494,7 +2494,8 @@ out:
 }
 EXPORT_SYMBOL(generic_cont_expand_simple);
 
-static int cont_expand_zero(struct file *file, struct address_space *mapping,
+static int cont_expand_zero(const struct kiocb *iocb,
+			    struct address_space *mapping,
 			    loff_t pos, loff_t *bytes)
 {
 	struct inode *inode = mapping->host;
@@ -2518,12 +2519,12 @@ static int cont_expand_zero(struct file *file, struct address_space *mapping,
 		}
 		len = PAGE_SIZE - zerofrom;
 
-		err = aops->write_begin(file, mapping, curpos, len,
+		err = aops->write_begin(iocb, mapping, curpos, len,
 					    &folio, &fsdata);
 		if (err)
 			goto out;
 		folio_zero_range(folio, offset_in_folio(folio, curpos), len);
-		err = aops->write_end(file, mapping, curpos, len, len,
+		err = aops->write_end(iocb, mapping, curpos, len, len,
 						folio, fsdata);
 		if (err < 0)
 			goto out;
@@ -2551,12 +2552,12 @@ static int cont_expand_zero(struct file *file, struct address_space *mapping,
 		}
 		len = offset - zerofrom;
 
-		err = aops->write_begin(file, mapping, curpos, len,
+		err = aops->write_begin(iocb, mapping, curpos, len,
 					    &folio, &fsdata);
 		if (err)
 			goto out;
 		folio_zero_range(folio, offset_in_folio(folio, curpos), len);
-		err = aops->write_end(file, mapping, curpos, len, len,
+		err = aops->write_end(iocb, mapping, curpos, len, len,
 						folio, fsdata);
 		if (err < 0)
 			goto out;
@@ -2571,17 +2572,16 @@ out:
  * For moronic filesystems that do not allow holes in file.
  * We may have to extend the file.
  */
-int cont_write_begin(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len,
-			struct folio **foliop, void **fsdata,
-			get_block_t *get_block, loff_t *bytes)
+int cont_write_begin(const struct kiocb *iocb, struct address_space *mapping,
+		     loff_t pos, unsigned len, struct folio **foliop,
+		     void **fsdata, get_block_t *get_block, loff_t *bytes)
 {
 	struct inode *inode = mapping->host;
 	unsigned int blocksize = i_blocksize(inode);
 	unsigned int zerofrom;
 	int err;
 
-	err = cont_expand_zero(file, mapping, pos, bytes);
+	err = cont_expand_zero(iocb, mapping, pos, bytes);
 	if (err)
 		return err;