diff options
| author | Toshi Kani <toshi.kani@hpe.com> | 2016-05-10 10:23:53 -0600 |
|---|---|---|
| committer | Vishal Verma <vishal.l.verma@intel.com> | 2016-05-17 00:44:11 -0600 |
| commit | 2d96afc8f70ef86c66a0b5d80c24a27d6dd13df3 (patch) | |
| tree | 094e60ebc2d1ecd365c8d2e38a1502d0e6c36999 /fs/block_dev.c | |
| parent | 2af3a8159cd204fc8437ed2f75863f0fb930f0d0 (diff) | |
block: Add bdev_dax_supported() for dax mount checks
DAX imposes additional requirements to a device. Add
bdev_dax_supported() which performs all the precondition checks
necessary for filesystem to mount the device with dax option.
Also add a new check to verify if a partition is aligned by 4KB.
When a partition is unaligned, any dax read/write access fails,
except for metadata update.
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@fb.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
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>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | fs/block_dev.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 91e0ec0233c0..518cde62c01c 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -509,6 +509,51 @@ long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) } EXPORT_SYMBOL_GPL(bdev_direct_access); +/** + * bdev_dax_supported() - Check if the device supports dax for filesystem + * @sb: The superblock of the device + * @blocksize: The block size of the device + * + * This is a library function for filesystems to check if the block device + * can be mounted with dax option. + * + * Return: negative errno if unsupported, 0 if supported. + */ +int bdev_dax_supported(struct super_block *sb, int blocksize) +{ + struct blk_dax_ctl dax = { + .sector = 0, + .size = PAGE_SIZE, + }; + int err; + + if (blocksize != PAGE_SIZE) { + vfs_msg(sb, KERN_ERR, "error: unsupported blocksize for dax"); + return -EINVAL; + } + + err = bdev_direct_access(sb->s_bdev, &dax); + if (err < 0) { + switch (err) { + case -EOPNOTSUPP: + vfs_msg(sb, KERN_ERR, + "error: device does not support dax"); + break; + case -EINVAL: + vfs_msg(sb, KERN_ERR, + "error: unaligned partition for dax"); + break; + default: + vfs_msg(sb, KERN_ERR, + "error: dax access failed (%d)", err); + } + return err; + } + + return 0; +} +EXPORT_SYMBOL_GPL(bdev_dax_supported); + /* * pseudo-fs */ |