Merge tag 'vfs-6.10.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This reworks the netfslib writeback implementation so that pages read
  from the cache are written to the cache through ->writepages(),
  thereby allowing the fscache page flag to be retired.

  The reworking also:

   - builds on top of the new writeback_iter() infrastructure

   - makes it possible to use vectored write RPCs as discontiguous
     streams of pages can be accommodated

   - makes it easier to do simultaneous content crypto and stream
     division

   - provides support for retrying writes and re-dividing a stream

   - replaces the ->launder_folio() op, so that ->writepages() is used
     instead

   - uses mempools to allocate the netfs_io_request and
     netfs_io_subrequest structs to avoid allocation failure in the
     writeback path

  Some code that uses the fscache page flag is retained for
  compatibility purposes with nfs and ceph. The code is switched to
  using the synonymous private_2 label instead and marked with
  deprecation comments.

  The merge commit contains additional details on the new algorithm that
  I've left out of here as it would probably be excessively detailed.

  On top of the netfslib infrastructure this contains the work to
  convert cifs over to netfslib"

* tag 'vfs-6.10.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (38 commits)
  cifs: Enable large folio support
  cifs: Remove some code that's no longer used, part 3
  cifs: Remove some code that's no longer used, part 2
  cifs: Remove some code that's no longer used, part 1
  cifs: Cut over to using netfslib
  cifs: Implement netfslib hooks
  cifs: Make add_credits_and_wake_if() clear deducted credits
  cifs: Add mempools for cifs_io_request and cifs_io_subrequest structs
  cifs: Set zero_point in the copy_file_range() and remap_file_range()
  cifs: Move cifs_loose_read_iter() and cifs_file_write_iter() to file.c
  cifs: Replace the writedata replay bool with a netfs sreq flag
  cifs: Make wait_mtu_credits take size_t args
  cifs: Use more fields from netfs_io_subrequest
  cifs: Replace cifs_writedata with a wrapper around netfs_io_subrequest
  cifs: Replace cifs_readdata with a wrapper around netfs_io_subrequest
  cifs: Use alternative invalidation to using launder_folio
  netfs, afs: Use writeback retry to deal with alternate keys
  netfs: Miscellaneous tidy ups
  netfs: Remove the old writeback code
  netfs: Cut over to using new writeback code
  ...

2 files changed, 58 insertions, 3 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 30de18c4fd28..1d6b3a369077 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1540,7 +1540,7 @@ EXPORT_SYMBOL(folio_end_private_2);
  * folio_wait_private_2 - Wait for PG_private_2 to be cleared on a folio.
  * @folio: The folio to wait on.
  *
- * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio.
+ * Wait for PG_private_2 to be cleared on a folio.
  */
 void folio_wait_private_2(struct folio *folio)
 {
@@ -1553,8 +1553,8 @@ EXPORT_SYMBOL(folio_wait_private_2);
  * folio_wait_private_2_killable - Wait for PG_private_2 to be cleared on a folio.
  * @folio: The folio to wait on.
  *
- * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio or until a
- * fatal signal is received by the calling task.
+ * Wait for PG_private_2 to be cleared on a folio or until a fatal signal is
+ * received by the calling task.
  *
  * Return:
  * - 0 if successful.
@@ -4134,6 +4134,60 @@ bool filemap_release_folio(struct folio *folio, gfp_t gfp)
 }
 EXPORT_SYMBOL(filemap_release_folio);
 
+/**
+ * filemap_invalidate_inode - Invalidate/forcibly write back a range of an inode's pagecache
+ * @inode: The inode to flush
+ * @flush: Set to write back rather than simply invalidate.
+ * @start: First byte to in range.
+ * @end: Last byte in range (inclusive), or LLONG_MAX for everything from start
+ *       onwards.
+ *
+ * Invalidate all the folios on an inode that contribute to the specified
+ * range, possibly writing them back first.  Whilst the operation is
+ * undertaken, the invalidate lock is held to prevent new folios from being
+ * installed.
+ */
+int filemap_invalidate_inode(struct inode *inode, bool flush,
+			     loff_t start, loff_t end)
+{
+	struct address_space *mapping = inode->i_mapping;
+	pgoff_t first = start >> PAGE_SHIFT;
+	pgoff_t last = end >> PAGE_SHIFT;
+	pgoff_t nr = end == LLONG_MAX ? ULONG_MAX : last - first + 1;
+
+	if (!mapping || !mapping->nrpages || end < start)
+		goto out;
+
+	/* Prevent new folios from being added to the inode. */
+	filemap_invalidate_lock(mapping);
+
+	if (!mapping->nrpages)
+		goto unlock;
+
+	unmap_mapping_pages(mapping, first, nr, false);
+
+	/* Write back the data if we're asked to. */
+	if (flush) {
+		struct writeback_control wbc = {
+			.sync_mode	= WB_SYNC_ALL,
+			.nr_to_write	= LONG_MAX,
+			.range_start	= start,
+			.range_end	= end,
+		};
+
+		filemap_fdatawrite_wbc(mapping, &wbc);
+	}
+
+	/* Wait for writeback to complete on all folios and discard. */
+	truncate_inode_pages_range(mapping, start, end);
+
+unlock:
+	filemap_invalidate_unlock(mapping);
+out:
+	return filemap_check_errors(mapping);
+}
+EXPORT_SYMBOL_GPL(filemap_invalidate_inode);
+
 #ifdef CONFIG_CACHESTAT_SYSCALL
 /**
  * filemap_cachestat() - compute the page cache statistics of a mapping
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3e19b87049db..06fc89d981e8 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2546,6 +2546,7 @@ done:
 	folio_batch_release(&wbc->fbatch);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(writeback_iter);
 
 /**
  * write_cache_pages - walk the list of dirty pages of the given address space and write all of them.