blob: 2d3b6a498d632752a95109b2d699fe7de36afec7 [file] [log] [blame]
* 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
* 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 log;
struct xlog_ticket;
struct xfs_mount;
* Macros, structures, prototypes for internal log manager use.
#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_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) / \
#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) ? \
#define XLOG_TOTAL_REC_SHIFT(log) \
BTOBB(XLOG_MAX_ICLOGS << (xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? \
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));
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;
* 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 */
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_FLAGS \
#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 */
#define XLOG_TAIL_WARN 0x10 /* log tail verify warning issued */
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_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 {
wait_queue_head_t t_wait; /* ticket wait queue */
struct list_head t_queue; /* reserve/write queue */
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;
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_IRIX_BE 3
/* our fmt */
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 {
wait_queue_head_t ic_force_wait;
wait_queue_head_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 */
/* 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 CIL context is used to aggregate per-transaction details as well be
* passed to the iclog for checkpoint post-commit processing. After being
* passed to the iclog, another context needs to be allocated for tracking the
* next set of transactions to be aggregated into a checkpoint.
struct xfs_cil;
struct xfs_cil_ctx {
struct xfs_cil *cil;
xfs_lsn_t sequence; /* chkpt sequence # */
xfs_lsn_t start_lsn; /* first LSN of chkpt commit */
xfs_lsn_t commit_lsn; /* chkpt commit record lsn */
struct xlog_ticket *ticket; /* chkpt ticket */
int nvecs; /* number of regions */
int space_used; /* aggregate size of regions */
struct list_head busy_extents; /* busy extents in chkpt */
struct xfs_log_vec *lv_chain; /* logvecs being pushed */
xfs_log_callback_t log_cb; /* completion callback hook. */
struct list_head committing; /* ctx committing list */
* Committed Item List structure
* This structure is used to track log items that have been committed but not
* yet written into the log. It is used only when the delayed logging mount
* option is enabled.
* This structure tracks the list of committing checkpoint contexts so
* we can avoid the problem of having to hold out new transactions during a
* flush until we have a the commit record LSN of the checkpoint. We can
* traverse the list of committing contexts in xlog_cil_push_lsn() to find a
* sequence match and extract the commit LSN directly from there. If the
* checkpoint is still in the process of committing, we can block waiting for
* the commit LSN to be determined as well. This should make synchronous
* operations almost as efficient as the old logging methods.
struct xfs_cil {
struct log *xc_log;
struct list_head xc_cil;
spinlock_t xc_cil_lock;
struct xfs_cil_ctx *xc_ctx;
struct rw_semaphore xc_ctx_lock;
struct list_head xc_committing;
wait_queue_head_t xc_commit_wait;
xfs_lsn_t xc_current_sequence;
* The amount of log space we allow the CIL to aggregate is difficult to size.
* Whatever we choose, we have to make sure we can get a reservation for the
* log space effectively, that it is large enough to capture sufficient
* relogging to reduce log buffer IO significantly, but it is not too large for
* the log or induces too much latency when writing out through the iclogs. We
* track both space consumed and the number of vectors in the checkpoint
* context, so we need to decide which to use for limiting.
* Every log buffer we write out during a push needs a header reserved, which
* is at least one sector and more for v2 logs. Hence we need a reservation of
* at least 512 bytes per 32k of log space just for the LR headers. That means
* 16KB of reservation per megabyte of delayed logging space we will consume,
* plus various headers. The number of headers will vary based on the num of
* io vectors, so limiting on a specific number of vectors is going to result
* in transactions of varying size. IOWs, it is more consistent to track and
* limit space consumed in the log rather than by the number of objects being
* logged in order to prevent checkpoint ticket overruns.
* Further, use of static reservations through the log grant mechanism is
* problematic. It introduces a lot of complexity (e.g. reserve grant vs write
* grant) and a significant deadlock potential because regranting write space
* can block on log pushes. Hence if we have to regrant log space during a log
* push, we can deadlock.
* However, we can avoid this by use of a dynamic "reservation stealing"
* technique during transaction commit whereby unused reservation space in the
* transaction ticket is transferred to the CIL ctx commit ticket to cover the
* space needed by the checkpoint transaction. This means that we never need to
* specifically reserve space for the CIL checkpoint transaction, nor do we
* need to regrant space once the checkpoint completes. This also means the
* checkpoint transaction ticket is specific to the checkpoint context, rather
* than the CIL itself.
* With dynamic reservations, we can effectively make up arbitrary limits for
* the checkpoint size so long as they don't violate any other size rules.
* Recovery imposes a rule that no transaction exceed half the log, so we are
* limited by that. Furthermore, the log transaction reservation subsystem
* tries to keep 25% of the log free, so we need to keep below that limit or we
* risk running out of free log space to start any new transactions.
* In order to keep background CIL push efficient, we will set a lower
* threshold at which background pushing is attempted without blocking current
* transaction commits. A separate, higher bound defines when CIL pushes are
* enforced to ensure we stay within our maximum checkpoint size bounds.
* threshold, yet give us plenty of space for aggregation on large logs.
#define XLOG_CIL_SPACE_LIMIT(log) (log->l_logsize >> 3)
#define XLOG_CIL_HARD_SPACE_LIMIT(log) (3 * (log->l_logsize >> 4))
* 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_cil *l_cilp; /* CIL 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 list_head *l_buf_cancel_table;
int l_iclog_hsize; /* size of iclog header */
int l_iclog_heads; /* # of iclog header sectors */
uint l_sectBBsize; /* sector size in BBs (2^n) */
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 */
wait_queue_head_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 */
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 */
* l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
* read without needing to hold specific locks. To avoid operations
* contending with other hot objects, place each of them on a separate
* cacheline.
/* lsn of last LR on disk */
atomic64_t l_last_sync_lsn ____cacheline_aligned_in_smp;
/* lsn of 1st LR with unflushed * buffers */
atomic64_t l_tail_lsn ____cacheline_aligned_in_smp;
* ticket grant locks, queues and accounting have their own cachlines
* as these are quite hot and can be operated on concurrently.
spinlock_t l_grant_reserve_lock ____cacheline_aligned_in_smp;
struct list_head l_reserveq;
atomic64_t l_grant_reserve_head;
spinlock_t l_grant_write_lock ____cacheline_aligned_in_smp;
struct list_head l_writeq;
atomic64_t l_grant_write_head;
/* The following field are used for debugging; need to hold icloglock */
#ifdef DEBUG
char *l_iclog_bak[XLOG_MAX_ICLOGS];
} xlog_t;
#define XLOG_BUF_CANCEL_BUCKET(log, blkno) \
((log)->l_buf_cancel_table + ((__uint64_t)blkno % XLOG_BC_TABLE_SIZE))
#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_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 kmem_zone_t *xfs_log_ticket_zone;
struct xlog_ticket *xlog_ticket_alloc(struct log *log, int unit_bytes,
int count, char client, uint xflags,
int alloc_flags);
static inline void
xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)
*ptr += bytes;
*len -= bytes;
*off += bytes;
void xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
int xlog_write(struct log *log, struct xfs_log_vec *log_vector,
struct xlog_ticket *tic, xfs_lsn_t *start_lsn,
xlog_in_core_t **commit_iclog, uint flags);
* When we crack an atomic LSN, we sample it first so that the value will not
* change while we are cracking it into the component values. This means we
* will always get consistent component values to work from. This should always
* be used to sample and crack LSNs that are stored and updated in atomic
* variables.
static inline void
xlog_crack_atomic_lsn(atomic64_t *lsn, uint *cycle, uint *block)
xfs_lsn_t val = atomic64_read(lsn);
*cycle = CYCLE_LSN(val);
*block = BLOCK_LSN(val);
* Calculate and assign a value to an atomic LSN variable from component pieces.
static inline void
xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
atomic64_set(lsn, xlog_assign_lsn(cycle, block));
* When we crack the grant head, we sample it first so that the value will not
* change while we are cracking it into the component values. This means we
* will always get consistent component values to work from.
static inline void
xlog_crack_grant_head_val(int64_t val, int *cycle, int *space)
*cycle = val >> 32;
*space = val & 0xffffffff;
static inline void
xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
xlog_crack_grant_head_val(atomic64_read(head), cycle, space);
static inline int64_t
xlog_assign_grant_head_val(int cycle, int space)
return ((int64_t)cycle << 32) | space;
static inline void
xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
atomic64_set(head, xlog_assign_grant_head_val(cycle, space));
* Committed Item List interfaces
int xlog_cil_init(struct log *log);
void xlog_cil_init_post_recovery(struct log *log);
void xlog_cil_destroy(struct log *log);
* CIL force routines
xfs_lsn_t xlog_cil_force_lsn(struct log *log, xfs_lsn_t sequence);
static inline void
xlog_cil_force(struct log *log)
xlog_cil_force_lsn(log, log->l_cilp->xc_current_sequence);
* 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.
* Wrapper function for waiting on a wait queue serialised against wakeups
* by a spinlock. This matches the semantics of all the wait queues used in the
* log code.
static inline void xlog_wait(wait_queue_head_t *wq, spinlock_t *lock)
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(wq, &wait);
remove_wait_queue(wq, &wait);
#endif /* __KERNEL__ */
#endif /* __XFS_LOG_PRIV_H__ */