zfs/include/sys/zil.h

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012 by Delphix. All rights reserved.
 */

/* Portions Copyright 2010 Robert Milkowski */

#ifndef	_SYS_ZIL_H
#define	_SYS_ZIL_H

#include <sys/types.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/dmu.h>

#ifdef	__cplusplus
extern "C" {
#endif

struct dsl_pool;
struct dsl_dataset;

/*
 * Intent log format:
 *
 * Each objset has its own intent log.  The log header (zil_header_t)
 * for objset N's intent log is kept in the Nth object of the SPA's
 * intent_log objset.  The log header points to a chain of log blocks,
 * each of which contains log records (i.e., transactions) followed by
 * a log block trailer (zil_trailer_t).  The format of a log record
 * depends on the record (or transaction) type, but all records begin
 * with a common structure that defines the type, length, and txg.
 */

/*
 * Intent log header - this on disk structure holds fields to manage
 * the log.  All fields are 64 bit to easily handle cross architectures.
 */
typedef struct zil_header {
	uint64_t zh_claim_txg;	/* txg in which log blocks were claimed */
	uint64_t zh_replay_seq;	/* highest replayed sequence number */
	blkptr_t zh_log;	/* log chain */
	uint64_t zh_claim_blk_seq; /* highest claimed block sequence number */
	uint64_t zh_flags;	/* header flags */
	uint64_t zh_claim_lr_seq; /* highest claimed lr sequence number */
	uint64_t zh_pad[3];
} zil_header_t;

/*
 * zh_flags bit settings
 */
#define	ZIL_REPLAY_NEEDED	0x1	/* replay needed - internal only */
#define	ZIL_CLAIM_LR_SEQ_VALID	0x2	/* zh_claim_lr_seq field is valid */

/*
 * Log block chaining.
 *
 * Log blocks are chained together. Originally they were chained at the
 * end of the block. For performance reasons the chain was moved to the
 * beginning of the block which allows writes for only the data being used.
 * The older position is supported for backwards compatability.
 *
 * The zio_eck_t contains a zec_cksum which for the intent log is
 * the sequence number of this log block. A seq of 0 is invalid.
 * The zec_cksum is checked by the SPA against the sequence
 * number passed in the blk_cksum field of the blkptr_t
 */
typedef struct zil_chain {
	uint64_t zc_pad;
	blkptr_t zc_next_blk;	/* next block in chain */
	uint64_t zc_nused;	/* bytes in log block used */
	zio_eck_t zc_eck;	/* block trailer */
} zil_chain_t;

#define	ZIL_MIN_BLKSZ	4096ULL

/*
 * The words of a log block checksum.
 */
#define	ZIL_ZC_GUID_0	0
#define	ZIL_ZC_GUID_1	1
#define	ZIL_ZC_OBJSET	2
#define	ZIL_ZC_SEQ	3

typedef enum zil_create {
	Z_FILE,
	Z_DIR,
	Z_XATTRDIR,
} zil_create_t;

/*
 * size of xvattr log section.
 * its composed of lr_attr_t + xvattr bitmap + 2 64 bit timestamps
 * for create time and a single 64 bit integer for all of the attributes,
 * and 4 64 bit integers (32 bytes) for the scanstamp.
 *
 */

#define	ZIL_XVAT_SIZE(mapsize) \
	sizeof (lr_attr_t) + (sizeof (uint32_t) * (mapsize - 1)) + \
	(sizeof (uint64_t) * 7)

/*
 * Size of ACL in log.  The ACE data is padded out to properly align
 * on 8 byte boundary.
 */

#define	ZIL_ACE_LENGTH(x)	(roundup(x, sizeof (uint64_t)))

/*
 * Intent log transaction types and record structures
 */
#define	TX_CREATE		1	/* Create file */
#define	TX_MKDIR		2	/* Make directory */
#define	TX_MKXATTR		3	/* Make XATTR directory */
#define	TX_SYMLINK		4	/* Create symbolic link to a file */
#define	TX_REMOVE		5	/* Remove file */
#define	TX_RMDIR		6	/* Remove directory */
#define	TX_LINK			7	/* Create hard link to a file */
#define	TX_RENAME		8	/* Rename a file */
#define	TX_WRITE		9	/* File write */
#define	TX_TRUNCATE		10	/* Truncate a file */
#define	TX_SETATTR		11	/* Set file attributes */
#define	TX_ACL_V0		12	/* Set old formatted ACL */
#define	TX_ACL			13	/* Set ACL */
#define	TX_CREATE_ACL		14	/* create with ACL */
#define	TX_CREATE_ATTR		15	/* create + attrs */
#define	TX_CREATE_ACL_ATTR 	16	/* create with ACL + attrs */
#define	TX_MKDIR_ACL		17	/* mkdir with ACL */
#define	TX_MKDIR_ATTR		18	/* mkdir with attr */
#define	TX_MKDIR_ACL_ATTR	19	/* mkdir with ACL + attrs */
#define	TX_WRITE2		20	/* dmu_sync EALREADY write */
#define	TX_MAX_TYPE		21	/* Max transaction type */

/*
 * The transactions for mkdir, symlink, remove, rmdir, link, and rename
 * may have the following bit set, indicating the original request
 * specified case-insensitive handling of names.
 */
#define	TX_CI	((uint64_t)0x1 << 63) /* case-insensitive behavior requested */

/*
 * Transactions for write, truncate, setattr, acl_v0, and acl can be logged
 * out of order.  For convenience in the code, all such records must have
 * lr_foid at the same offset.
 */
#define	TX_OOO(txtype)			\
	((txtype) == TX_WRITE ||	\
	(txtype) == TX_TRUNCATE ||	\
	(txtype) == TX_SETATTR ||	\
	(txtype) == TX_ACL_V0 ||	\
	(txtype) == TX_ACL ||		\
	(txtype) == TX_WRITE2)

/*
 * Format of log records.
 * The fields are carefully defined to allow them to be aligned
 * and sized the same on sparc & intel architectures.
 * Each log record has a common structure at the beginning.
 *
 * The log record on disk (lrc_seq) holds the sequence number of all log
 * records which is used to ensure we don't replay the same record.
 */
typedef struct {			/* common log record header */
	uint64_t	lrc_txtype;	/* intent log transaction type */
	uint64_t	lrc_reclen;	/* transaction record length */
	uint64_t	lrc_txg;	/* dmu transaction group number */
	uint64_t	lrc_seq;	/* see comment above */
} lr_t;

/*
 * Common start of all out-of-order record types (TX_OOO() above).
 */
typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* object id */
} lr_ooo_t;

/*
 * Handle option extended vattr attributes.
 *
 * Whenever new attributes are added the version number
 * will need to be updated as will code in
 * zfs_log.c and zfs_replay.c
 */
typedef struct {
	uint32_t	lr_attr_masksize; /* number of elements in array */
	uint32_t	lr_attr_bitmap; /* First entry of array */
	/* remainder of array and any additional fields */
} lr_attr_t;

/*
 * log record for creates without optional ACL.
 * This log record does support optional xvattr_t attributes.
 */
typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_doid;	/* object id of directory */
	uint64_t	lr_foid;	/* object id of created file object */
	uint64_t	lr_mode;	/* mode of object */
	uint64_t	lr_uid;		/* uid of object */
	uint64_t	lr_gid;		/* gid of object */
	uint64_t	lr_gen;		/* generation (txg of creation) */
	uint64_t	lr_crtime[2];	/* creation time */
	uint64_t	lr_rdev;	/* rdev of object to create */
	/* name of object to create follows this */
	/* for symlinks, link content follows name */
	/* for creates with xvattr data, the name follows the xvattr info */
} lr_create_t;

/*
 * FUID ACL record will be an array of ACEs from the original ACL.
 * If this array includes ephemeral IDs, the record will also include
 * an array of log-specific FUIDs to replace the ephemeral IDs.
 * Only one copy of each unique domain will be present, so the log-specific
 * FUIDs will use an index into a compressed domain table.  On replay this
 * information will be used to construct real FUIDs (and bypass idmap,
 * since it may not be available).
 */

/*
 * Log record for creates with optional ACL
 * This log record is also used for recording any FUID
 * information needed for replaying the create.  If the
 * file doesn't have any actual ACEs then the lr_aclcnt
 * would be zero.
 *
 * After lr_acl_flags, there are a lr_acl_bytes number of variable sized ace's.
 * If create is also setting xvattr's, then acl data follows xvattr.
 * If ACE FUIDs are needed then they will follow the xvattr_t.  Following
 * the FUIDs will be the domain table information.  The FUIDs for the owner
 * and group will be in lr_create.  Name follows ACL data.
 */
typedef struct {
	lr_create_t	lr_create;	/* common create portion */
	uint64_t	lr_aclcnt;	/* number of ACEs in ACL */
	uint64_t	lr_domcnt;	/* number of unique domains */
	uint64_t	lr_fuidcnt;	/* number of real fuids */
	uint64_t	lr_acl_bytes;	/* number of bytes in ACL */
	uint64_t	lr_acl_flags;	/* ACL flags */
} lr_acl_create_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_doid;	/* obj id of directory */
	/* name of object to remove follows this */
} lr_remove_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_doid;	/* obj id of directory */
	uint64_t	lr_link_obj;	/* obj id of link */
	/* name of object to link follows this */
} lr_link_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_sdoid;	/* obj id of source directory */
	uint64_t	lr_tdoid;	/* obj id of target directory */
	/* 2 strings: names of source and destination follow this */
} lr_rename_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* file object to write */
	uint64_t	lr_offset;	/* offset to write to */
	uint64_t	lr_length;	/* user data length to write */
	uint64_t	lr_blkoff;	/* no longer used */
	blkptr_t	lr_blkptr;	/* spa block pointer for replay */
	/* write data will follow for small writes */
} lr_write_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* object id of file to truncate */
	uint64_t	lr_offset;	/* offset to truncate from */
	uint64_t	lr_length;	/* length to truncate */
} lr_truncate_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* file object to change attributes */
	uint64_t	lr_mask;	/* mask of attributes to set */
	uint64_t	lr_mode;	/* mode to set */
	uint64_t	lr_uid;		/* uid to set */
	uint64_t	lr_gid;		/* gid to set */
	uint64_t	lr_size;	/* size to set */
	uint64_t	lr_atime[2];	/* access time */
	uint64_t	lr_mtime[2];	/* modification time */
	/* optional attribute lr_attr_t may be here */
} lr_setattr_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* obj id of file */
	uint64_t	lr_aclcnt;	/* number of acl entries */
	/* lr_aclcnt number of ace_t entries follow this */
} lr_acl_v0_t;

typedef struct {
	lr_t		lr_common;	/* common portion of log record */
	uint64_t	lr_foid;	/* obj id of file */
	uint64_t	lr_aclcnt;	/* number of ACEs in ACL */
	uint64_t	lr_domcnt;	/* number of unique domains */
	uint64_t	lr_fuidcnt;	/* number of real fuids */
	uint64_t	lr_acl_bytes;	/* number of bytes in ACL */
	uint64_t	lr_acl_flags;	/* ACL flags */
	/* lr_acl_bytes number of variable sized ace's follows */
} lr_acl_t;

/*
 * ZIL structure definitions, interface function prototype and globals.
 */

/*
 * Writes are handled in three different ways:
 *
 * WR_INDIRECT:
 *    In this mode, if we need to commit the write later, then the block
 *    is immediately written into the file system (using dmu_sync),
 *    and a pointer to the block is put into the log record.
 *    When the txg commits the block is linked in.
 *    This saves additionally writing the data into the log record.
 *    There are a few requirements for this to occur:
 *	- write is greater than zfs/zvol_immediate_write_sz
 *	- not using slogs (as slogs are assumed to always be faster
 *	  than writing into the main pool)
 *	- the write occupies only one block
 * WR_COPIED:
 *    If we know we'll immediately be committing the
 *    transaction (FSYNC or FDSYNC), the we allocate a larger
 *    log record here for the data and copy the data in.
 * WR_NEED_COPY:
 *    Otherwise we don't allocate a buffer, and *if* we need to
 *    flush the write later then a buffer is allocated and
 *    we retrieve the data using the dmu.
 */
typedef enum {
	WR_INDIRECT,	/* indirect - a large write (dmu_sync() data */
			/* and put blkptr in log, rather than actual data) */
	WR_COPIED,	/* immediate - data is copied into lr_write_t */
	WR_NEED_COPY,	/* immediate - data needs to be copied if pushed */
	WR_NUM_STATES	/* number of states */
} itx_wr_state_t;

typedef void (*zil_callback_t)(void *data);

typedef struct itx {
	list_node_t	itx_node;	/* linkage on zl_itx_list */
	void		*itx_private;	/* type-specific opaque data */
	itx_wr_state_t	itx_wr_state;	/* write state */
	uint8_t		itx_sync;	/* synchronous transaction */
	zil_callback_t	itx_callback;   /* Called when the itx is persistent */
	void		*itx_callback_data; /* User data for the callback */
	uint64_t	itx_sod;	/* record size on disk */
	uint64_t	itx_oid;	/* object id */
	lr_t		itx_lr;		/* common part of log record */
	/* followed by type-specific part of lr_xx_t and its immediate data */
} itx_t;

/*
 * Used for zil kstat.
 */
typedef struct zil_stats {
	/*
	 * Number of times a ZIL commit (e.g. fsync) has been requested.
	 */
	kstat_named_t zil_commit_count;

	/*
	 * Number of times the ZIL has been flushed to stable storage.
	 * This is less than zil_commit_count when commits are "merged"
	 * (see the documentation above zil_commit()).
	 */
	kstat_named_t zil_commit_writer_count;

	/*
	 * Number of transactions (reads, writes, renames, etc.)
	 * that have been commited.
	 */
	kstat_named_t zil_itx_count;

	/*
	 * See the documentation for itx_wr_state_t above.
	 * Note that "bytes" accumulates the length of the transactions
	 * (i.e. data), not the actual log record sizes.
	 */
	kstat_named_t zil_itx_indirect_count;
	kstat_named_t zil_itx_indirect_bytes;
	kstat_named_t zil_itx_copied_count;
	kstat_named_t zil_itx_copied_bytes;
	kstat_named_t zil_itx_needcopy_count;
	kstat_named_t zil_itx_needcopy_bytes;

	/*
	 * Transactions which have been allocated to the "normal"
	 * (i.e. not slog) storage pool. Note that "bytes" accumulate
	 * the actual log record sizes - which do not include the actual
	 * data in case of indirect writes.
	 */
	kstat_named_t zil_itx_metaslab_normal_count;
	kstat_named_t zil_itx_metaslab_normal_bytes;

	/*
	 * Transactions which have been allocated to the "slog" storage pool.
	 * If there are no separate log devices, this is the same as the
	 * "normal" pool.
	 */
	kstat_named_t zil_itx_metaslab_slog_count;
	kstat_named_t zil_itx_metaslab_slog_bytes;
} zil_stats_t;

extern zil_stats_t zil_stats;

#define	ZIL_STAT_INCR(stat, val) \
    atomic_add_64(&zil_stats.stat.value.ui64, (val));
#define	ZIL_STAT_BUMP(stat) \
    ZIL_STAT_INCR(stat, 1);

typedef int zil_parse_blk_func_t(zilog_t *zilog, blkptr_t *bp, void *arg,
    uint64_t txg);
typedef int zil_parse_lr_func_t(zilog_t *zilog, lr_t *lr, void *arg,
    uint64_t txg);
typedef int (*const zil_replay_func_t)(void *, char *, boolean_t);
typedef int zil_get_data_t(void *arg, lr_write_t *lr, char *dbuf, zio_t *zio);

extern int zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
    zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg);

extern void	zil_init(void);
extern void	zil_fini(void);

extern zilog_t	*zil_alloc(objset_t *os, zil_header_t *zh_phys);
extern void	zil_free(zilog_t *zilog);

extern zilog_t	*zil_open(objset_t *os, zil_get_data_t *get_data);
extern void	zil_close(zilog_t *zilog);

extern void	zil_replay(objset_t *os, void *arg,
    zil_replay_func_t replay_func[TX_MAX_TYPE]);
extern boolean_t zil_replaying(zilog_t *zilog, dmu_tx_t *tx);
extern void	zil_destroy(zilog_t *zilog, boolean_t keep_first);
extern void	zil_destroy_sync(zilog_t *zilog, dmu_tx_t *tx);

extern itx_t	*zil_itx_create(uint64_t txtype, size_t lrsize);
extern void	zil_itx_destroy(itx_t *itx);
extern void	zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx);

extern void	zil_commit(zilog_t *zilog, uint64_t oid);

extern int	zil_vdev_offline(const char *osname, void *txarg);
extern int	zil_claim(struct dsl_pool *dp,
    struct dsl_dataset *ds, void *txarg);
extern int 	zil_check_log_chain(struct dsl_pool *dp,
    struct dsl_dataset *ds, void *tx);
extern void	zil_sync(zilog_t *zilog, dmu_tx_t *tx);
extern void	zil_clean(zilog_t *zilog, uint64_t synced_txg);

extern int	zil_suspend(const char *osname, void **cookiep);
extern void	zil_resume(void *cookie);

extern void	zil_add_block(zilog_t *zilog, const blkptr_t *bp);
extern int	zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp);

extern void	zil_set_sync(zilog_t *zilog, uint64_t syncval);

extern void	zil_set_logbias(zilog_t *zilog, uint64_t slogval);

extern int zil_replay_disable;

#ifdef	__cplusplus
}
#endif

#endif	/* _SYS_ZIL_H */