Commit b5b18160 authored Oct 27, 2020 by Jan Kara Committed by Theodore Ts'o Oct 28, 2020

ext4: fix mmap write protection for data=journal mode



Commit afb585a9 "ext4: data=journal: write-protect pages on
j_submit_inode_data_buffers()") added calls ext4_jbd2_inode_add_write()
to track inode ranges whose mappings need to get write-protected during
transaction commits.  However the added calls use wrong start of a range
(0 instead of page offset) and so write protection is not necessarily
effective.  Use correct range start to fix the problem.

Fixes: afb585a9 ("ext4: data=journal: write-protect pages on j_submit_inode_data_buffers()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201027132751.29858-1-jack@suse.cz


Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent ea4b01d9

fs/ext4/inode.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1918,7 +1918,7 @@ static int __ext4_journalled_writepage(struct page *page,
		}
		if (ret == 0)
		ret = err;
		err = ext4_jbd2_inode_add_write(handle, inode, 0, len);
		err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
		if (ret == 0)
		ret = err;
		EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
		@@ -6159,7 +6159,8 @@ retry_alloc:
		if (ext4_walk_page_buffers(handle, page_buffers(page),
		0, len, NULL, write_end_fn))
		goto out_error;
		if (ext4_jbd2_inode_add_write(handle, inode, 0, len))
		if (ext4_jbd2_inode_add_write(handle, inode,
		page_offset(page), len))
		goto out_error;
		ext4_set_inode_state(inode, EXT4_STATE_JDATA);
		} else {

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