Commit 14b393ee authored by Kent Overstreet's avatar Kent Overstreet Committed by Kent Overstreet
Browse files

bcachefs: Subvolumes, snapshots 



This patch adds subvolume.c - support for the subvolumes and snapshots
btrees and related data types and on disk data structures. The next
patches will start hooking up this new code to existing code.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
parent 8948fc8f

fs/bcachefs/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ bcachefs-y := \ 
	replicas.o		\

	siphash.o		\

	six.o			\

	subvolume.o		\

	super.o			\

	super-io.o		\

	sysfs.o			\

fs/bcachefs/bcachefs.h

+23 −0
Original line number Diff line number Diff line
@@ -381,6 +381,8 @@ enum gc_phase { 
	GC_PHASE_BTREE_alloc,

	GC_PHASE_BTREE_quotas,

	GC_PHASE_BTREE_reflink,

	GC_PHASE_BTREE_subvolumes,

	GC_PHASE_BTREE_snapshots,



	GC_PHASE_PENDING_DELETE,

};
@@ -564,6 +566,21 @@ struct btree_path_buf { 


#define REPLICAS_DELTA_LIST_MAX	(1U << 16)



struct snapshot_t {

	u32			parent;

	u32			children[2];

	u32			subvol; /* Nonzero only if a subvolume points to this node: */

	u32			equiv;

};



typedef struct {

	u32		subvol;

	u64		inum;

} subvol_inum;



#define BCACHEFS_ROOT_SUBVOL_INUM					\

	((subvol_inum) { BCACHEFS_ROOT_SUBVOL,	BCACHEFS_ROOT_INO })



struct bch_fs {

	struct closure		cl;
@@ -635,6 +652,12 @@ struct bch_fs { 
	struct closure		sb_write;

	struct mutex		sb_lock;



	/* snapshot.c: */

	GENRADIX(struct snapshot_t) snapshots;

	struct bch_snapshot_table __rcu *snapshot_table;

	struct mutex		snapshot_table_lock;

	struct work_struct	snapshot_delete_work;



	/* BTREE CACHE */

	struct bio_set		btree_bio;

	struct workqueue_struct	*io_complete_wq;

fs/bcachefs/bcachefs_format.h

+52 −3
Original line number Diff line number Diff line
@@ -346,7 +346,9 @@ static inline void bkey_init(struct bkey *k) 
	x(inline_data,		17)			\

	x(btree_ptr_v2,		18)			\

	x(indirect_inline_data,	19)			\

	x(alloc_v2,		20)

	x(alloc_v2,		20)			\

	x(subvolume,		21)			\

	x(snapshot,		22)



enum bch_bkey_type {

#define x(name, nr) KEY_TYPE_##name	= nr,
@@ -690,6 +692,10 @@ struct bch_inode_generation { 
	__le32			pad;

} __attribute__((packed, aligned(8)));



/*

 * bi_subvol and bi_parent_subvol are only set for subvolume roots:

 */



#define BCH_INODE_FIELDS()			\

	x(bi_atime,			96)	\

	x(bi_ctime,			96)	\
@@ -713,7 +719,9 @@ struct bch_inode_generation { 
	x(bi_erasure_code,		16)	\

	x(bi_fields_set,		16)	\

	x(bi_dir,			64)	\

	x(bi_dir_offset,		64)

	x(bi_dir_offset,		64)	\

	x(bi_subvol,			32)	\

	x(bi_parent_subvol,		32)



/* subset of BCH_INODE_FIELDS */

#define BCH_INODE_OPTS()			\
@@ -796,6 +804,9 @@ struct bch_dirent { 
	__u8			d_name[];

} __attribute__((packed, aligned(8)));



#define DT_SUBVOL	16

#define BCH_DT_MAX	17



#define BCH_NAME_MAX	(U8_MAX * sizeof(u64) -				\

			 sizeof(struct bkey) -				\

			 offsetof(struct bch_dirent, d_name))
@@ -932,6 +943,42 @@ struct bch_inline_data { 
	u8			data[0];

};



/* Subvolumes: */



#define SUBVOL_POS_MIN		POS(0, 1)

#define SUBVOL_POS_MAX		POS(0, S32_MAX)

#define BCACHEFS_ROOT_SUBVOL	1



struct bch_subvolume {

	struct bch_val		v;

	__le32			flags;

	__le32			snapshot;

	__le64			inode;

};



LE32_BITMASK(BCH_SUBVOLUME_RO,		struct bch_subvolume, flags,  0,  1)

/*

 * We need to know whether a subvolume is a snapshot so we can know whether we

 * can delete it (or whether it should just be rm -rf'd)

 */

LE32_BITMASK(BCH_SUBVOLUME_SNAP,	struct bch_subvolume, flags,  1,  2)



/* Snapshots */



struct bch_snapshot {

	struct bch_val		v;

	__le32			flags;

	__le32			parent;

	__le32			children[2];

	__le32			subvol;

	__le32			pad;

};



LE32_BITMASK(BCH_SNAPSHOT_DELETED,	struct bch_snapshot, flags,  0,  1)



/* True if a subvolume points to this snapshot node: */

LE32_BITMASK(BCH_SNAPSHOT_SUBVOL,	struct bch_snapshot, flags,  1,  2)



/* Optional/variable size superblock sections: */



struct bch_sb_field {
@@ -1702,7 +1749,9 @@ LE32_BITMASK(JSET_NO_FLUSH, struct jset, flags, 5, 6); 
	x(alloc,	4)			\

	x(quotas,	5)			\

	x(stripes,	6)			\

	x(reflink,	7)

	x(reflink,	7)			\

	x(subvolumes,	8)			\

	x(snapshots,	9)



enum btree_id {

#define x(kwd, val) BTREE_ID_##kwd = val,

fs/bcachefs/bcachefs_ioctl.h

+15 −0
Original line number Diff line number Diff line
@@ -78,6 +78,9 @@ struct bch_ioctl_incremental { 
#define BCH_IOCTL_DISK_RESIZE	_IOW(0xbc,	14,  struct bch_ioctl_disk_resize)

#define BCH_IOCTL_DISK_RESIZE_JOURNAL _IOW(0xbc,15,  struct bch_ioctl_disk_resize_journal)



#define BCH_IOCTL_SUBVOLUME_CREATE _IOW(0xbc,	16,  struct bch_ioctl_subvolume)

#define BCH_IOCTL_SUBVOLUME_DESTROY _IOW(0xbc,	17,  struct bch_ioctl_subvolume)



/* ioctl below act on a particular file, not the filesystem as a whole: */



#define BCHFS_IOC_REINHERIT_ATTRS	_IOR(0xbc, 64, const char __user *)
@@ -349,4 +352,16 @@ struct bch_ioctl_disk_resize_journal { 
	__u64			nbuckets;

};



struct bch_ioctl_subvolume {

	__u32			flags;

	__u32			dirfd;

	__u16			mode;

	__u16			pad[3];

	__u64			dst_ptr;

	__u64			src_ptr;

};



#define BCH_SUBVOL_SNAPSHOT_CREATE	(1U << 0)

#define BCH_SUBVOL_SNAPSHOT_RO		(1U << 1)



#endif /* _BCACHEFS_IOCTL_H */

fs/bcachefs/bkey_methods.c

+5 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include "inode.h"

#include "quota.h"

#include "reflink.h"

#include "subvolume.h"

#include "xattr.h"



const char * const bch2_bkey_types[] = {
@@ -126,6 +127,10 @@ static unsigned bch2_key_types_allowed[] = { 
	[BKEY_TYPE_reflink] =

		(1U << KEY_TYPE_reflink_v)|

		(1U << KEY_TYPE_indirect_inline_data),

	[BKEY_TYPE_subvolumes] =

		(1U << KEY_TYPE_subvolume),

	[BKEY_TYPE_snapshots] =

		(1U << KEY_TYPE_snapshot),

	[BKEY_TYPE_btree] =

		(1U << KEY_TYPE_btree_ptr)|

		(1U << KEY_TYPE_btree_ptr_v2),