dax, xfs, ext4: compile out iomap-dax paths in the FS_DAX=n case

Tetsuo reports:

  fs/built-in.o: In function `xfs_file_iomap_end':
  xfs_iomap.c:(.text+0xe0ef9): undefined reference to `put_dax'
  fs/built-in.o: In function `xfs_file_iomap_begin':
  xfs_iomap.c:(.text+0xe1a7f): undefined reference to `dax_get_by_host'
  make: *** [vmlinux] Error 1
  $ grep DAX .config
  CONFIG_DAX=m
  # CONFIG_DEV_DAX is not set
  # CONFIG_FS_DAX is not set

When FS_DAX=n we can/must throw away the dax code in filesystems.
Implement 'fs_' versions of dax_get_by_host() and put_dax() that are
nops in the FS_DAX=n case.

Cc: <[email protected]>
Cc: <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: "Darrick J. Wong" <[email protected]>
Cc: Ross Zwisler <[email protected]>
Tested-by: Tony Luck <[email protected]>
Fixes: ef51042472f5 ("block, dax: move 'select DAX' from BLOCK to FS_DAX")
Reported-by: Tetsuo Handa <[email protected]>
Signed-off-by: Dan Williams <[email protected]>

0 files changed, 0 insertions, 0 deletions