Merge tag 'vfs-6.11.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull iomap updates from Christian Brauner:
 "This contains some minor work for the iomap subsystem:

   - Add documentation on the design of iomap and how to port to it

   - Optimize iomap_read_folio()

   - Bring back the change to iomap_write_end() to no increase i_size.

     This is accompanied by a change to xfs to reserve blocks for
     truncating large realtime inodes to avoid exposing stale data when
     iomap_write_end() stops increasing i_size"

* tag 'vfs-6.11.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: don't increase i_size in iomap_write_end()
  xfs: reserve blocks for truncating large realtime inode
  Documentation: the design of iomap and how to port
  iomap: Optimize iomap_read_folio

1 files changed, 14 insertions, 1 deletions

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ff222827e550..a00dcbc77e12 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -17,6 +17,8 @@
 #include "xfs_da_btree.h"
 #include "xfs_attr.h"
 #include "xfs_trans.h"
+#include "xfs_trans_space.h"
+#include "xfs_bmap_btree.h"
 #include "xfs_trace.h"
 #include "xfs_icache.h"
 #include "xfs_symlink.h"
@@ -811,6 +813,7 @@ xfs_setattr_size(
 	struct xfs_trans	*tp;
 	int			error;
 	uint			lock_flags = 0;
+	uint			resblks = 0;
 	bool			did_zeroing = false;
 
 	xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL);
@@ -917,7 +920,17 @@ xfs_setattr_size(
 			return error;
 	}
 
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	/*
+	 * For realtime inode with more than one block rtextsize, we need the
+	 * block reservation for bmap btree block allocations/splits that can
+	 * happen since it could split the tail written extent and convert the
+	 * right beyond EOF one to unwritten.
+	 */
+	if (xfs_inode_has_bigrtalloc(ip))
+		resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, resblks,
+				0, 0, &tp);
 	if (error)
 		return error;