[mirror_zfs-debian.git] / 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, 2017 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

/*
 * ziltest is by and large an ugly hack, but very useful in
 * checking replay without tedious work.
 * When running ziltest we want to keep all itx's and so maintain
 * a single list in the zl_itxg[] that uses a high txg: ZILTEST_TXG
 * We subtract TXG_CONCURRENT_STATES to allow for common code.
 */
#define ZILTEST_TXG (UINT64_MAX - TXG_CONCURRENT_STATES)

/*
 * 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)

/*
 * The number of dnode slots consumed by the object is stored in the 8
 * unused upper bits of the object ID. We subtract 1 from the value
 * stored on disk for compatibility with implementations that don't
 * support large dnodes. The slot count for a single-slot dnode will
 * contain 0 for those bits to preserve the log record format for
 * "small" dnodes.
 */
#define LR_FOID_GET_SLOTS(oid) (BF64_GET((oid), 56, 8) + 1)
#define LR_FOID_SET_SLOTS(oid, x) BF64_SET((oid), 56, 8, (x) - 1)
#define LR_FOID_GET_OBJ(oid) BF64_GET((oid), 0, DN_MAX_OBJECT_SHIFT)
#define LR_FOID_SET_OBJ(oid, x) BF64_SET((oid), 0, DN_MAX_OBJECT_SHIFT, (x))

/*
 * 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), then 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_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 */