diff mbox

[v3,3/5] ext4: Add alignment check for DAX mount

Message ID 1462494596-20938-4-git-send-email-toshi.kani@hpe.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kani, Toshi May 6, 2016, 12:29 a.m. UTC
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_supports_dax() to perform proper precondition checks
which includes this partition alignment check.

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 |   11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

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Comments

Jan Kara May 9, 2016, 8:15 a.m. UTC | #1
On Thu 05-05-16 18:29:54, Toshi Kani wrote:
> 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_supports_dax() to perform proper precondition checks
> which includes this partition alignment check.
> 
> 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>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
diff mbox

Patch

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 304c712..e7ca71c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3416,16 +3416,9 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	if (sbi->s_mount_opt & EXT4_MOUNT_DAX) {
-		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,
-					"error: device does not support dax");
+		err = bdev_supports_dax(sb, blocksize);
+		if (err)
 			goto failed_mount;
-		}
 	}
 
 	if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {