From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
This sets S_DAX in inode->i_flags, which can be used with
IS_DAX().
The dax option is restricted to non multi-device mounts.
dax interacts with the device directly instead of using bio, so
all bio-hooks which we use for multi-device cannot be performed
here. While regular read/writes could be manipulated with
RAID0/1, mmap() is still an issue.
Auto-setting free space tree, because dealing with free space
inode (specifically readpages) is a nightmare.
Auto-setting nodatasum because we don't get callback for writing
checksums after mmap()s.
Store the dax_device in fs_info which will be used in iomap code.
Question: Since we have only one dax device, I thought fs_info is
the best place. However, should it moved to btrfs_device?
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/btrfs/ctree.h | 2 ++
fs/btrfs/disk-io.c | 4 ++++
fs/btrfs/ioctl.c | 5 ++++-
fs/btrfs/super.c | 26 ++++++++++++++++++++++++++
4 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b3642367a595..8ca1c0d120f4 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1067,6 +1067,7 @@ struct btrfs_fs_info {
u32 metadata_ratio;
void *bdev_holder;
+ struct dax_device *dax_dev;
/* private scrub information */
struct mutex scrub_lock;
@@ -1442,6 +1443,7 @@ 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/disk-io.c b/fs/btrfs/disk-io.c
index 6fe9197f6ee4..2bbb63b2fcff 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -16,6 +16,7 @@
#include <linux/uuid.h>
#include <linux/semaphore.h>
#include <linux/error-injection.h>
+#include <linux/dax.h>
#include <linux/crc32c.h>
#include <linux/sched/mm.h>
#include <asm/unaligned.h>
@@ -2805,6 +2806,8 @@ int open_ctree(struct super_block *sb,
goto fail_alloc;
}
+ fs_info->dax_dev = fs_dax_get_by_bdev(fs_devices->latest_bdev);
+
/*
* We want to check superblock checksum, the type is stored inside.
* Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
@@ -4043,6 +4046,7 @@ void close_ctree(struct btrfs_fs_info *fs_info)
#endif
btrfs_close_devices(fs_info->fs_devices);
+ fs_put_dax(fs_info->dax_dev);
btrfs_mapping_tree_free(&fs_info->mapping_tree);
percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ec2d8919e7fb..e66426e7692d 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 120e4340792a..2d448b9d6004 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"},
@@ -745,6 +747,28 @@ 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;
+ case Opt_dax:
+#ifdef CONFIG_FS_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);
+ btrfs_warn(info, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk\n");
+ btrfs_set_and_info(info, NODATASUM,
+ "auto-setting nodatasum (dax)");
+ btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
+ btrfs_set_and_info(info, FREE_SPACE_TREE,
+ "auto-setting free space tree (dax)");
+ break;
+#else
+ btrfs_err(info,
+ "DAX option not supported\n");
+ ret = -EINVAL;
+ goto out;
+#endif
case Opt_enospc_debug:
btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
break;
@@ -1335,6 +1359,8 @@ 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
