fs/ext4: Make DAX mount option a tri-state
Ira Weiny authored

We add 'always', 'never', and 'inode' (default).  '-o dax' continues to
operate the same which is equivalent to 'always'.  This new
functionality is limited to ext4 only.

Specifically we introduce a 2nd DAX mount flag EXT4_MOUNT2_DAX_NEVER and set
it and EXT4_MOUNT_DAX_ALWAYS appropriately for the mode.

We also force EXT4_MOUNT2_DAX_NEVER if !CONFIG_FS_DAX.

Finally, EXT4_MOUNT2_DAX_INODE is used solely to detect if the user
specified that option for printing.
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarIra Weiny <ira.weiny@intel.com>

Link: https://lore.kernel.org/r/20200528150003.828793-7-ira.weiny@intel.com

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
9cb20f94
Linux kernel
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