Messages in this thread Patch in this message | | | From | Toshi Kani <> | Subject | [PATCH v2 1/3] ext4: Add alignment check for DAX mount | Date | Mon, 2 May 2016 12:42:56 -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.
Call bdev_direct_access to check the alignment 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> Cc: Christoph Hellwig <hch@infradead.org> Cc: Boaz Harrosh <boaz@plexistor.com> --- fs/ext4/super.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 304c712..51ac78e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3416,14 +3416,30 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) } if (sbi->s_mount_opt & EXT4_MOUNT_DAX) { + struct blk_dax_ctl dax = { + .sector = 0, + .size = PAGE_SIZE, + }; if (blocksize != PAGE_SIZE) { ext4_msg(sb, KERN_ERR, "error: unsupported blocksize for dax"); goto failed_mount; } - if (!sb->s_bdev->bd_disk->fops->direct_access) { - ext4_msg(sb, KERN_ERR, + err = bdev_direct_access(sb->s_bdev, &dax); + if (err < 0) { + switch (err) { + case -EOPNOTSUPP: + ext4_msg(sb, KERN_ERR, "error: device does not support dax"); + break; + case -EINVAL: + ext4_msg(sb, KERN_ERR, + "error: unaligned partition for dax"); + break; + default: + ext4_msg(sb, KERN_ERR, + "error: dax access failed (%d)", err); + } goto failed_mount; } }
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