When DAX calls _ext4_get_block() and the file offset points to a hole we
currently don't set bh->b_size. When we re-enable PMD faults DAX will
need bh->b_size to tell it the size of the hole so it can decide whether to
fault in a 4 KiB zero page or a 2 MiB zero page.
_ext4_get_block() has the hole size information from ext4_map_blocks(), so
populate bh->b_size.
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
fs/ext4/inode.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3131747..1808013 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -759,6 +759,9 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock,
ext4_update_bh_state(bh, map.m_flags);
bh->b_size = inode->i_sb->s_blocksize * map.m_len;
ret = 0;
+ } else if (ret == 0) {
+ /* hole case, need to fill in bh->b_size */
+ bh->b_size = inode->i_sb->s_blocksize * map.m_len;
}
return ret;
}
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>