[PATCH 01/10] btrfs: create a mount option for dax

[Goldwyn Rodrigues]

From: Goldwyn Rodrigues <rgold...@suse.com>

Also, set the inode->i_flags to S_DAX

Signed-off-by: Goldwyn Rodrigues <rgold...@suse.com>
---
 fs/btrfs/ctree.h |  1 +
 fs/btrfs/ioctl.c |  5 ++++-
 fs/btrfs/super.c | 15 +++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 68f322f600a0..5cc470fa6a40 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1353,6 +1353,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct 
btrfs_fs_info *info)
 #define BTRFS_MOUNT_FREE_SPACE_TREE    (1 << 26)
 #define BTRFS_MOUNT_NOLOGREPLAY                (1 << 27)
 #define BTRFS_MOUNT_REF_VERIFY         (1 << 28)
+#define BTRFS_MOUNT_DAX                        (1 << 29)
 
 #define BTRFS_DEFAULT_COMMIT_INTERVAL  (30)
 #define BTRFS_DEFAULT_MAX_INLINE       (2048)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 802a628e9f7d..e9146c157816 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -149,8 +149,11 @@ void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
        if (binode->flags & BTRFS_INODE_DIRSYNC)
                new_fl |= S_DIRSYNC;
 
+       if ((btrfs_test_opt(btrfs_sb(inode->i_sb), DAX)) && 
S_ISREG(inode->i_mode))
+               new_fl |= S_DAX;
+
        set_mask_bits(&inode->i_flags,
-                     S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
+                     S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC | 
S_DAX,
                      new_fl);
 }
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 645fc81e2a94..035263b61cf5 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -326,6 +326,7 @@ enum {
        Opt_treelog, Opt_notreelog,
        Opt_usebackuproot,
        Opt_user_subvol_rm_allowed,
+       Opt_dax,
 
        /* Deprecated options */
        Opt_alloc_start,
@@ -393,6 +394,7 @@ static const match_table_t tokens = {
        {Opt_notreelog, "notreelog"},
        {Opt_usebackuproot, "usebackuproot"},
        {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
+       {Opt_dax, "dax"},
 
        /* Deprecated options */
        {Opt_alloc_start, "alloc_start=%s"},
@@ -739,6 +741,17 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char 
*options,
                case Opt_user_subvol_rm_allowed:
                        btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
                        break;
+#ifdef CONFIG_FS_DAX
+               case Opt_dax:
+                       if (btrfs_super_num_devices(info->super_copy) > 1) {
+                               btrfs_info(info,
+                                          "dax not supported for multi-device 
btrfs partition\n");
+                               ret = -EOPNOTSUPP;
+                               goto out;
+                       }
+                       btrfs_set_opt(info->mount_opt, DAX);
+                       break;
+#endif
                case Opt_enospc_debug:
                        btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
                        break;
@@ -1329,6 +1342,8 @@ static int btrfs_show_options(struct seq_file *seq, 
struct dentry *dentry)
                seq_puts(seq, ",clear_cache");
        if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
                seq_puts(seq, ",user_subvol_rm_allowed");
+       if (btrfs_test_opt(info, DAX))
+               seq_puts(seq, ",dax");
        if (btrfs_test_opt(info, ENOSPC_DEBUG))
                seq_puts(seq, ",enospc_debug");
        if (btrfs_test_opt(info, AUTO_DEFRAG))
-- 
2.16.4