From 4f91b042af212ca0b610e43f9a975ddc7f0d0923 Mon Sep 17 00:00:00 2001 From: Hungyu Lin Date: Thu, 29 Oct 2026 01:36:16 +0000 Subject: [PATCH] ext2: preserve IOMAP_F_DIRTY for extending direct writes ext2_iomap_begin() sets IOMAP_F_DIRTY for writes that may extend i_size, but clears the flag after ext2_get_blocks(). When the write uses an existing mapped block, iomap can then use FUA and skip generic_write_sync(), even though ext2_dio_write_end_io() updates the inode size. An O_DSYNC write can therefore return without persisting the new size. For example, on a FUA-capable device, a 512-byte O_DIRECT|O_DSYNC write at offset 512 into a fsynced one-byte file returns successfully and extends the in-memory size to 1024, while an immediate read of the on-disk inode still shows size 1. An explicit fsync persists the new size. Move setting of IOMAP_F_DIRTY after the initialization. Fixes: fb5de4358e1a ("ext2: Move direct-io to use iomap") Cc: stable@vger.kernel.org Signed-off-by: Hungyu Lin Link: https://patch.msgid.link/20261029013616.97194-1-dennylin0707@gmail.com Signed-off-by: Jan Kara --- fs/ext2/inode.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 723b31dc7dac..1989258aef8a 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -807,6 +807,12 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, (first_block << blkbits) < i_size_read(inode)) create = 0; + ret = ext2_get_blocks(inode, first_block, max_blocks, + &bno, &new, &boundary, create); + if (ret < 0) + return ret; + + iomap->flags = 0; /* * Writes that span EOF might trigger an IO size update on completion, * so consider them to be dirty for the purposes of O_DSYNC even if @@ -814,13 +820,6 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, */ if ((flags & IOMAP_WRITE) && offset + length > i_size_read(inode)) iomap->flags |= IOMAP_F_DIRTY; - - ret = ext2_get_blocks(inode, first_block, max_blocks, - &bno, &new, &boundary, create); - if (ret < 0) - return ret; - - iomap->flags = 0; iomap->offset = (u64)first_block << blkbits; iomap->bdev = inode->i_sb->s_bdev;