Messages in this thread Patch in this message | | | From | Toshi Kani <> | Subject | [PATCH 1/3] ext4: Add alignment check for DAX mount | Date | Fri, 29 Apr 2016 14:39:33 -0600 |
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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.
Add alignment check to ext4_fill_super() when -o dax is specified.
Reported-by: Micah Parrish <micah.parrish@hpe.com> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> --- fs/ext4/super.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 304c712..90a8670 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3421,6 +3421,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) "error: unsupported blocksize for dax"); goto failed_mount; } + if (sb->s_bdev->bd_part->start_sect % (PAGE_SIZE / 512) || + sb->s_bdev->bd_part->nr_sects % (PAGE_SIZE / 512)) { + ext4_msg(sb, KERN_ERR, + "error: unaligned partition for dax"); + goto failed_mount; + } if (!sb->s_bdev->bd_disk->fops->direct_access) { ext4_msg(sb, KERN_ERR, "error: device does not support dax");
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