1 files changed, 22 insertions, 24 deletions

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index b3910dfcb56d..72a3e6db2524 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -83,13 +83,13 @@ static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
  * netfs_perform_write - Copy data into the pagecache.
  * @iocb: The operation parameters
  * @iter: The source buffer
- * @netfs_group: Grouping for dirty pages (eg. ceph snaps).
+ * @netfs_group: Grouping for dirty folios (eg. ceph snaps).
  *
- * Copy data into pagecache pages attached to the inode specified by @iocb.
+ * Copy data into pagecache folios attached to the inode specified by @iocb.
  * The caller must hold appropriate inode locks.
  *
- * Dirty pages are tagged with a netfs_folio struct if they're not up to date
- * to indicate the range modified.  Dirty pages may also be tagged with a
+ * Dirty folios are tagged with a netfs_folio struct if they're not up to date
+ * to indicate the range modified.  Dirty folios may also be tagged with a
  * netfs-specific grouping such that data from an old group gets flushed before
  * a new one is started.
  */
@@ -115,8 +115,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 	size_t max_chunk = mapping_max_folio_size(mapping);
 	bool maybe_trouble = false;
 
-	if (unlikely(test_bit(NETFS_ICTX_WRITETHROUGH, &ctx->flags) ||
-		     iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC))
+	if (unlikely(iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC))
 	    ) {
 		wbc_attach_fdatawrite_inode(&wbc, mapping->host);
 
@@ -223,11 +222,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		 * we try to read it.
 		 */
 		if (fpos >= ctx->zero_point) {
-			zero_user_segment(&folio->page, 0, offset);
+			folio_zero_segment(folio, 0, offset);
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
 			if (unlikely(copied == 0))
 				goto copy_failed;
-			zero_user_segment(&folio->page, offset + copied, flen);
+			folio_zero_segment(folio, offset + copied, flen);
 			__netfs_set_group(folio, netfs_group);
 			folio_mark_uptodate(folio);
 			trace_netfs_folio(folio, netfs_modify_and_clear);
@@ -386,7 +385,7 @@ out:
 		wbc_detach_inode(&wbc);
 		if (ret2 == -EIOCBQUEUED)
 			return ret2;
-		if (ret == 0)
+		if (ret == 0 && ret2 < 0)
 			ret = ret2;
 	}
 
@@ -407,7 +406,7 @@ EXPORT_SYMBOL(netfs_perform_write);
  * netfs_buffered_write_iter_locked - write data to a file
  * @iocb:	IO state structure (file, offset, etc.)
  * @from:	iov_iter with data to write
- * @netfs_group: Grouping for dirty pages (eg. ceph snaps).
+ * @netfs_group: Grouping for dirty folios (eg. ceph snaps).
  *
  * This function does all the work needed for actually writing data to a
  * file. It does all basic checks, removes SUID from the file, updates
@@ -491,7 +490,9 @@ EXPORT_SYMBOL(netfs_file_write_iter);
 
 /*
  * Notification that a previously read-only page is about to become writable.
- * Note that the caller indicates a single page of a multipage folio.
+ * The caller indicates the precise page that needs to be written to, but
+ * we only track group on a per-folio basis, so we block more often than
+ * we might otherwise.
  */
 vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group)
 {
@@ -501,7 +502,7 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file_inode(file);
 	struct netfs_inode *ictx = netfs_inode(inode);
-	vm_fault_t ret = VM_FAULT_RETRY;
+	vm_fault_t ret = VM_FAULT_NOPAGE;
 	int err;
 
 	_enter("%lx", folio->index);
@@ -510,21 +511,15 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 
 	if (folio_lock_killable(folio) < 0)
 		goto out;
-	if (folio->mapping != mapping) {
-		folio_unlock(folio);
-		ret = VM_FAULT_NOPAGE;
-		goto out;
-	}
-
-	if (folio_wait_writeback_killable(folio)) {
-		ret = VM_FAULT_LOCKED;
-		goto out;
-	}
+	if (folio->mapping != mapping)
+		goto unlock;
+	if (folio_wait_writeback_killable(folio) < 0)
+		goto unlock;
 
 	/* Can we see a streaming write here? */
 	if (WARN_ON(!folio_test_uptodate(folio))) {
-		ret = VM_FAULT_SIGBUS | VM_FAULT_LOCKED;
-		goto out;
+		ret = VM_FAULT_SIGBUS;
+		goto unlock;
 	}
 
 	group = netfs_folio_group(folio);
@@ -559,5 +554,8 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 out:
 	sb_end_pagefault(inode->i_sb);
 	return ret;
+unlock:
+	folio_unlock(folio);
+	goto out;
 }
 EXPORT_SYMBOL(netfs_page_mkwrite);