fuse: fix "direct_io" private mmap

[linux-2.6] / fs / xfs / xfs_log_priv.h

/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_LOG_PRIV_H__
#define __XFS_LOG_PRIV_H__

struct xfs_buf;
struct ktrace;
struct log;
struct xlog_ticket;
struct xfs_buf_cancel;
struct xfs_mount;

/*
 * Macros, structures, prototypes for internal log manager use.
 */

#define XLOG_MIN_ICLOGS         2
#define XLOG_MAX_ICLOGS         8
#define XLOG_HEADER_MAGIC_NUM   0xFEEDbabe      /* Invalid cycle number */
#define XLOG_VERSION_1          1
#define XLOG_VERSION_2          2               /* Large IClogs, Log sunit */
#define XLOG_VERSION_OKBITS     (XLOG_VERSION_1 | XLOG_VERSION_2)
#define XLOG_MIN_RECORD_BSIZE   (16*1024)       /* eventually 32k */
#define XLOG_BIG_RECORD_BSIZE   (32*1024)       /* 32k buffers */
#define XLOG_MAX_RECORD_BSIZE   (256*1024)
#define XLOG_HEADER_CYCLE_SIZE  (32*1024)       /* cycle data in header */
#define XLOG_MIN_RECORD_BSHIFT  14              /* 16384 == 1 << 14 */
#define XLOG_BIG_RECORD_BSHIFT  15              /* 32k == 1 << 15 */
#define XLOG_MAX_RECORD_BSHIFT  18              /* 256k == 1 << 18 */
#define XLOG_BTOLSUNIT(log, b)  (((b)+(log)->l_mp->m_sb.sb_logsunit-1) / \
                                 (log)->l_mp->m_sb.sb_logsunit)
#define XLOG_LSUNITTOB(log, su) ((su) * (log)->l_mp->m_sb.sb_logsunit)

#define XLOG_HEADER_SIZE        512

#define XLOG_REC_SHIFT(log) \
        BTOBB(1 << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
         XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))
#define XLOG_TOTAL_REC_SHIFT(log) \
        BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
         XLOG_MAX_RECORD_BSHIFT : XLOG_BIG_RECORD_BSHIFT))


static inline xfs_lsn_t xlog_assign_lsn(uint cycle, uint block)
{
        return ((xfs_lsn_t)cycle << 32) | block;
}

static inline uint xlog_get_cycle(char *ptr)
{
        if (be32_to_cpu(*(__be32 *)ptr) == XLOG_HEADER_MAGIC_NUM)
                return be32_to_cpu(*((__be32 *)ptr + 1));
        else
                return be32_to_cpu(*(__be32 *)ptr);
}

#define BLK_AVG(blk1, blk2)     ((blk1+blk2) >> 1)

#ifdef __KERNEL__

/*
 * get client id from packed copy.
 *
 * this hack is here because the xlog_pack code copies four bytes
 * of xlog_op_header containing the fields oh_clientid, oh_flags
 * and oh_res2 into the packed copy.
 *
 * later on this four byte chunk is treated as an int and the
 * client id is pulled out.
 *
 * this has endian issues, of course.
 */
static inline uint xlog_get_client_id(__be32 i)
{
        return be32_to_cpu(i) >> 24;
}

#define xlog_panic(args...)     cmn_err(CE_PANIC, ## args)
#define xlog_exit(args...)      cmn_err(CE_PANIC, ## args)
#define xlog_warn(args...)      cmn_err(CE_WARN, ## args)

/*
 * In core log state
 */
#define XLOG_STATE_ACTIVE    0x0001 /* Current IC log being written to */
#define XLOG_STATE_WANT_SYNC 0x0002 /* Want to sync this iclog; no more writes */
#define XLOG_STATE_SYNCING   0x0004 /* This IC log is syncing */
#define XLOG_STATE_DONE_SYNC 0x0008 /* Done syncing to disk */
#define XLOG_STATE_DO_CALLBACK \
                             0x0010 /* Process callback functions */
#define XLOG_STATE_CALLBACK  0x0020 /* Callback functions now */
#define XLOG_STATE_DIRTY     0x0040 /* Dirty IC log, not ready for ACTIVE status*/
#define XLOG_STATE_IOERROR   0x0080 /* IO error happened in sync'ing log */
#define XLOG_STATE_ALL       0x7FFF /* All possible valid flags */
#define XLOG_STATE_NOTUSED   0x8000 /* This IC log not being used */
#endif  /* __KERNEL__ */

/*
 * Flags to log operation header
 *
 * The first write of a new transaction will be preceded with a start
 * record, XLOG_START_TRANS.  Once a transaction is committed, a commit
 * record is written, XLOG_COMMIT_TRANS.  If a single region can not fit into
 * the remainder of the current active in-core log, it is split up into
 * multiple regions.  Each partial region will be marked with a
 * XLOG_CONTINUE_TRANS until the last one, which gets marked with XLOG_END_TRANS.
 *
 */
#define XLOG_START_TRANS        0x01    /* Start a new transaction */
#define XLOG_COMMIT_TRANS       0x02    /* Commit this transaction */
#define XLOG_CONTINUE_TRANS     0x04    /* Cont this trans into new region */
#define XLOG_WAS_CONT_TRANS     0x08    /* Cont this trans into new region */
#define XLOG_END_TRANS          0x10    /* End a continued transaction */
#define XLOG_UNMOUNT_TRANS      0x20    /* Unmount a filesystem transaction */

#ifdef __KERNEL__
/*
 * Flags to log ticket
 */
#define XLOG_TIC_INITED         0x1     /* has been initialized */
#define XLOG_TIC_PERM_RESERV    0x2     /* permanent reservation */
#define XLOG_TIC_IN_Q           0x4
#endif  /* __KERNEL__ */

#define XLOG_UNMOUNT_TYPE       0x556e  /* Un for Unmount */

/*
 * Flags for log structure
 */
#define XLOG_CHKSUM_MISMATCH    0x1     /* used only during recovery */
#define XLOG_ACTIVE_RECOVERY    0x2     /* in the middle of recovery */
#define XLOG_RECOVERY_NEEDED    0x4     /* log was recovered */
#define XLOG_IO_ERROR           0x8     /* log hit an I/O error, and being
                                           shutdown */
typedef __uint32_t xlog_tid_t;


#ifdef __KERNEL__
/*
 * Below are states for covering allocation transactions.
 * By covering, we mean changing the h_tail_lsn in the last on-disk
 * log write such that no allocation transactions will be re-done during
 * recovery after a system crash. Recovery starts at the last on-disk
 * log write.
 *
 * These states are used to insert dummy log entries to cover
 * space allocation transactions which can undo non-transactional changes
 * after a crash. Writes to a file with space
 * already allocated do not result in any transactions. Allocations
 * might include space beyond the EOF. So if we just push the EOF a
 * little, the last transaction for the file could contain the wrong
 * size. If there is no file system activity, after an allocation
 * transaction, and the system crashes, the allocation transaction
 * will get replayed and the file will be truncated. This could
 * be hours/days/... after the allocation occurred.
 *
 * The fix for this is to do two dummy transactions when the
 * system is idle. We need two dummy transaction because the h_tail_lsn
 * in the log record header needs to point beyond the last possible
 * non-dummy transaction. The first dummy changes the h_tail_lsn to
 * the first transaction before the dummy. The second dummy causes
 * h_tail_lsn to point to the first dummy. Recovery starts at h_tail_lsn.
 *
 * These dummy transactions get committed when everything
 * is idle (after there has been some activity).
 *
 * There are 5 states used to control this.
 *
 *  IDLE -- no logging has been done on the file system or
 *              we are done covering previous transactions.
 *  NEED -- logging has occurred and we need a dummy transaction
 *              when the log becomes idle.
 *  DONE -- we were in the NEED state and have committed a dummy
 *              transaction.
 *  NEED2 -- we detected that a dummy transaction has gone to the
 *              on disk log with no other transactions.
 *  DONE2 -- we committed a dummy transaction when in the NEED2 state.
 *
 * There are two places where we switch states:
 *
 * 1.) In xfs_sync, when we detect an idle log and are in NEED or NEED2.
 *      We commit the dummy transaction and switch to DONE or DONE2,
 *      respectively. In all other states, we don't do anything.
 *
 * 2.) When we finish writing the on-disk log (xlog_state_clean_log).
 *
 *      No matter what state we are in, if this isn't the dummy
 *      transaction going out, the next state is NEED.
 *      So, if we aren't in the DONE or DONE2 states, the next state
 *      is NEED. We can't be finishing a write of the dummy record
 *      unless it was committed and the state switched to DONE or DONE2.
 *
 *      If we are in the DONE state and this was a write of the
 *              dummy transaction, we move to NEED2.
 *
 *      If we are in the DONE2 state and this was a write of the
 *              dummy transaction, we move to IDLE.
 *
 *
 * Writing only one dummy transaction can get appended to
 * one file space allocation. When this happens, the log recovery
 * code replays the space allocation and a file could be truncated.
 * This is why we have the NEED2 and DONE2 states before going idle.
 */

#define XLOG_STATE_COVER_IDLE   0
#define XLOG_STATE_COVER_NEED   1
#define XLOG_STATE_COVER_DONE   2
#define XLOG_STATE_COVER_NEED2  3
#define XLOG_STATE_COVER_DONE2  4

#define XLOG_COVER_OPS          5


/* Ticket reservation region accounting */ 
#define XLOG_TIC_LEN_MAX        15

/*
 * Reservation region
 * As would be stored in xfs_log_iovec but without the i_addr which
 * we don't care about.
 */
typedef struct xlog_res {
        uint    r_len;  /* region length                :4 */
        uint    r_type; /* region's transaction type    :4 */
} xlog_res_t;

typedef struct xlog_ticket {
        sv_t               t_wait;       /* ticket wait queue            : 20 */
        struct xlog_ticket *t_next;      /*                              :4|8 */
        struct xlog_ticket *t_prev;      /*                              :4|8 */
        xlog_tid_t         t_tid;        /* transaction identifier       : 4  */
        atomic_t           t_ref;        /* ticket reference count       : 4  */
        int                t_curr_res;   /* current reservation in bytes : 4  */
        int                t_unit_res;   /* unit reservation in bytes    : 4  */
        char               t_ocnt;       /* original count               : 1  */
        char               t_cnt;        /* current count                : 1  */
        char               t_clientid;   /* who does this belong to;     : 1  */
        char               t_flags;      /* properties of reservation    : 1  */
        uint               t_trans_type; /* transaction type             : 4  */

        /* reservation array fields */
        uint               t_res_num;                    /* num in array : 4 */
        uint               t_res_num_ophdrs;             /* num op hdrs  : 4 */
        uint               t_res_arr_sum;                /* array sum    : 4 */
        uint               t_res_o_flow;                 /* sum overflow : 4 */
        xlog_res_t         t_res_arr[XLOG_TIC_LEN_MAX];  /* array of res : 8 * 15 */ 
} xlog_ticket_t;

#endif


typedef struct xlog_op_header {
        __be32     oh_tid;      /* transaction id of operation  :  4 b */
        __be32     oh_len;      /* bytes in data region         :  4 b */
        __u8       oh_clientid; /* who sent me this             :  1 b */
        __u8       oh_flags;    /*                              :  1 b */
        __u16      oh_res2;     /* 32 bit align                 :  2 b */
} xlog_op_header_t;


/* valid values for h_fmt */
#define XLOG_FMT_UNKNOWN  0
#define XLOG_FMT_LINUX_LE 1
#define XLOG_FMT_LINUX_BE 2
#define XLOG_FMT_IRIX_BE  3

/* our fmt */
#ifdef XFS_NATIVE_HOST
#define XLOG_FMT XLOG_FMT_LINUX_BE
#else
#define XLOG_FMT XLOG_FMT_LINUX_LE
#endif

typedef struct xlog_rec_header {
        __be32    h_magicno;    /* log record (LR) identifier           :  4 */
        __be32    h_cycle;      /* write cycle of log                   :  4 */
        __be32    h_version;    /* LR version                           :  4 */
        __be32    h_len;        /* len in bytes; should be 64-bit aligned: 4 */
        __be64    h_lsn;        /* lsn of this LR                       :  8 */
        __be64    h_tail_lsn;   /* lsn of 1st LR w/ buffers not committed: 8 */
        __be32    h_chksum;     /* may not be used; non-zero if used    :  4 */
        __be32    h_prev_block; /* block number to previous LR          :  4 */
        __be32    h_num_logops; /* number of log operations in this LR  :  4 */
        __be32    h_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE];
        /* new fields */
        __be32    h_fmt;        /* format of log record                 :  4 */
        uuid_t    h_fs_uuid;    /* uuid of FS                           : 16 */
        __be32    h_size;       /* iclog size                           :  4 */
} xlog_rec_header_t;

typedef struct xlog_rec_ext_header {
        __be32    xh_cycle;     /* write cycle of log                   : 4 */
        __be32    xh_cycle_data[XLOG_HEADER_CYCLE_SIZE / BBSIZE]; /*    : 256 */
} xlog_rec_ext_header_t;

#ifdef __KERNEL__

/*
 * Quite misnamed, because this union lays out the actual on-disk log buffer.
 */
typedef union xlog_in_core2 {
        xlog_rec_header_t       hic_header;
        xlog_rec_ext_header_t   hic_xheader;
        char                    hic_sector[XLOG_HEADER_SIZE];
} xlog_in_core_2_t;

/*
 * - A log record header is 512 bytes.  There is plenty of room to grow the
 *      xlog_rec_header_t into the reserved space.
 * - ic_data follows, so a write to disk can start at the beginning of
 *      the iclog.
 * - ic_forcewait is used to implement synchronous forcing of the iclog to disk.
 * - ic_next is the pointer to the next iclog in the ring.
 * - ic_bp is a pointer to the buffer used to write this incore log to disk.
 * - ic_log is a pointer back to the global log structure.
 * - ic_callback is a linked list of callback function/argument pairs to be
 *      called after an iclog finishes writing.
 * - ic_size is the full size of the header plus data.
 * - ic_offset is the current number of bytes written to in this iclog.
 * - ic_refcnt is bumped when someone is writing to the log.
 * - ic_state is the state of the iclog.
 *
 * Because of cacheline contention on large machines, we need to separate
 * various resources onto different cachelines. To start with, make the
 * structure cacheline aligned. The following fields can be contended on
 * by independent processes:
 *
 *      - ic_callback_*
 *      - ic_refcnt
 *      - fields protected by the global l_icloglock
 *
 * so we need to ensure that these fields are located in separate cachelines.
 * We'll put all the read-only and l_icloglock fields in the first cacheline,
 * and move everything else out to subsequent cachelines.
 */
typedef struct xlog_in_core {
        sv_t                    ic_force_wait;
        sv_t                    ic_write_wait;
        struct xlog_in_core     *ic_next;
        struct xlog_in_core     *ic_prev;
        struct xfs_buf          *ic_bp;
        struct log              *ic_log;
        int                     ic_size;
        int                     ic_offset;
        int                     ic_bwritecnt;
        unsigned short          ic_state;
        char                    *ic_datap;      /* pointer to iclog data */
#ifdef XFS_LOG_TRACE
        struct ktrace           *ic_trace;
#endif

        /* Callback structures need their own cacheline */
        spinlock_t              ic_callback_lock ____cacheline_aligned_in_smp;
        xfs_log_callback_t      *ic_callback;
        xfs_log_callback_t      **ic_callback_tail;

        /* reference counts need their own cacheline */
        atomic_t                ic_refcnt ____cacheline_aligned_in_smp;
        xlog_in_core_2_t        *ic_data;
#define ic_header       ic_data->hic_header
} xlog_in_core_t;

/*
 * The reservation head lsn is not made up of a cycle number and block number.
 * Instead, it uses a cycle number and byte number.  Logs don't expect to
 * overflow 31 bits worth of byte offset, so using a byte number will mean
 * that round off problems won't occur when releasing partial reservations.
 */
typedef struct log {
        /* The following fields don't need locking */
        struct xfs_mount        *l_mp;          /* mount point */
        struct xfs_ail          *l_ailp;        /* AIL log is working with */
        struct xfs_buf          *l_xbuf;        /* extra buffer for log
                                                 * wrapping */
        struct xfs_buftarg      *l_targ;        /* buftarg of log */
        uint                    l_flags;
        uint                    l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */
        struct xfs_buf_cancel   **l_buf_cancel_table;
        int                     l_iclog_hsize;  /* size of iclog header */
        int                     l_iclog_heads;  /* # of iclog header sectors */
        uint                    l_sectbb_log;   /* log2 of sector size in BBs */
        uint                    l_sectbb_mask;  /* sector size (in BBs)
                                                 * alignment mask */
        int                     l_iclog_size;   /* size of log in bytes */
        int                     l_iclog_size_log; /* log power size of log */
        int                     l_iclog_bufs;   /* number of iclog buffers */
        xfs_daddr_t             l_logBBstart;   /* start block of log */
        int                     l_logsize;      /* size of log in bytes */
        int                     l_logBBsize;    /* size of log in BB chunks */

        /* The following block of fields are changed while holding icloglock */
        sv_t                    l_flush_wait ____cacheline_aligned_in_smp;
                                                /* waiting for iclog flush */
        int                     l_covered_state;/* state of "covering disk
                                                 * log entries" */
        xlog_in_core_t          *l_iclog;       /* head log queue       */
        spinlock_t              l_icloglock;    /* grab to change iclog state */
        xfs_lsn_t               l_tail_lsn;     /* lsn of 1st LR with unflushed
                                                 * buffers */
        xfs_lsn_t               l_last_sync_lsn;/* lsn of last LR on disk */
        int                     l_curr_cycle;   /* Cycle number of log writes */
        int                     l_prev_cycle;   /* Cycle number before last
                                                 * block increment */
        int                     l_curr_block;   /* current logical log block */
        int                     l_prev_block;   /* previous logical log block */

        /* The following block of fields are changed while holding grant_lock */
        spinlock_t              l_grant_lock ____cacheline_aligned_in_smp;
        xlog_ticket_t           *l_reserve_headq;
        xlog_ticket_t           *l_write_headq;
        int                     l_grant_reserve_cycle;
        int                     l_grant_reserve_bytes;
        int                     l_grant_write_cycle;
        int                     l_grant_write_bytes;

#ifdef XFS_LOG_TRACE
        struct ktrace           *l_grant_trace;
#endif

        /* The following field are used for debugging; need to hold icloglock */
#ifdef DEBUG
        char                    *l_iclog_bak[XLOG_MAX_ICLOGS];
#endif

} xlog_t;

#define XLOG_FORCED_SHUTDOWN(log)       ((log)->l_flags & XLOG_IO_ERROR)


/* common routines */
extern xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp);
extern int       xlog_find_tail(xlog_t  *log,
                                xfs_daddr_t *head_blk,
                                xfs_daddr_t *tail_blk);
extern int       xlog_recover(xlog_t *log);
extern int       xlog_recover_finish(xlog_t *log);
extern void      xlog_pack_data(xlog_t *log, xlog_in_core_t *iclog, int);
extern void      xlog_recover_process_iunlinks(xlog_t *log);

extern struct xfs_buf *xlog_get_bp(xlog_t *, int);
extern void      xlog_put_bp(struct xfs_buf *);

extern kmem_zone_t      *xfs_log_ticket_zone;

/* iclog tracing */
#define XLOG_TRACE_GRAB_FLUSH  1
#define XLOG_TRACE_REL_FLUSH   2
#define XLOG_TRACE_SLEEP_FLUSH 3
#define XLOG_TRACE_WAKE_FLUSH  4

/*
 * Unmount record type is used as a pseudo transaction type for the ticket.
 * It's value must be outside the range of XFS_TRANS_* values.
 */
#define XLOG_UNMOUNT_REC_TYPE   (-1U)

#endif  /* __KERNEL__ */

#endif  /* __XFS_LOG_PRIV_H__ */