xfs: add initial DAX support
Add initial DAX support to XFS. To do this we need a new mount
option to turn DAX on filesystem, and we need to propagate this into
the inode flags whenever an inode is instantiated so that the
per-inode checks throughout the code Do The Right Thing.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 858e1e6..1fb16562 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -112,6 +112,8 @@
#define MNTOPT_DISCARD "discard" /* Discard unused blocks */
#define MNTOPT_NODISCARD "nodiscard" /* Do not discard unused blocks */
+#define MNTOPT_DAX "dax" /* Enable direct access to bdev pages */
+
/*
* Table driven mount option parser.
*
@@ -363,6 +365,10 @@
mp->m_flags |= XFS_MOUNT_DISCARD;
} else if (!strcmp(this_char, MNTOPT_NODISCARD)) {
mp->m_flags &= ~XFS_MOUNT_DISCARD;
+#ifdef CONFIG_FS_DAX
+ } else if (!strcmp(this_char, MNTOPT_DAX)) {
+ mp->m_flags |= XFS_MOUNT_DAX;
+#endif
} else {
xfs_warn(mp, "unknown mount option [%s].", this_char);
return -EINVAL;
@@ -452,8 +458,8 @@
}
struct proc_xfs_info {
- int flag;
- char *str;
+ uint64_t flag;
+ char *str;
};
STATIC int
@@ -474,6 +480,7 @@
{ XFS_MOUNT_GRPID, "," MNTOPT_GRPID },
{ XFS_MOUNT_DISCARD, "," MNTOPT_DISCARD },
{ XFS_MOUNT_SMALL_INUMS, "," MNTOPT_32BITINODE },
+ { XFS_MOUNT_DAX, "," MNTOPT_DAX },
{ 0, NULL }
};
static struct proc_xfs_info xfs_info_unset[] = {
@@ -1507,6 +1514,20 @@
if (XFS_SB_VERSION_NUM(&mp->m_sb) == XFS_SB_VERSION_5)
sb->s_flags |= MS_I_VERSION;
+ if (mp->m_flags & XFS_MOUNT_DAX) {
+ xfs_warn(mp,
+ "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+ if (sb->s_blocksize != PAGE_SIZE) {
+ xfs_alert(mp,
+ "Filesystem block size invalid for DAX Turning DAX off.");
+ mp->m_flags &= ~XFS_MOUNT_DAX;
+ } else if (!sb->s_bdev->bd_disk->fops->direct_access) {
+ xfs_alert(mp,
+ "Block device does not support DAX Turning DAX off.");
+ mp->m_flags &= ~XFS_MOUNT_DAX;
+ }
+ }
+
error = xfs_mountfs(mp);
if (error)
goto out_filestream_unmount;
