When a partition is not aligned by 4KB, mount -o dax succeeds,
but any read/write access to the filesystem fails, except for
metadata update.
Call bdev_direct_access to check the alignment when -o dax is
specified.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
---
fs/ext2/super.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index b78caf2..e636b56 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -922,14 +922,31 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
+ struct blk_dax_ctl dax = {
+ .sector = 0,
+ .size = PAGE_SIZE,
+ };
if (blocksize != PAGE_SIZE) {
ext2_msg(sb, KERN_ERR,
"error: unsupported blocksize for dax");
goto failed_mount;
}
- if (!sb->s_bdev->bd_disk->fops->direct_access) {
- ext2_msg(sb, KERN_ERR,
+ err = bdev_direct_access(sb->s_bdev, &dax);
+ if (err < 0) {
+ switch (err) {
+ case -EOPNOTSUPP:
+ ext2_msg(sb, KERN_ERR,
"error: device does not support dax");
+ break;
+ case -EINVAL:
+ ext2_msg(sb, KERN_ERR,
+ "error: unaligned partition for dax");
+ break;
+ default:
+ ext2_msg(sb, KERN_ERR,
+ "error: dax access failed (%d)", err);
+ break;
+ }
goto failed_mount;
}
}
--
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