1 files changed, 114 insertions, 4 deletions

diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 9cf695154451..8c072618965c 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -152,8 +152,6 @@ static inline uint xlog_get_client_id(__be32 i)
 #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__
 /*
@@ -379,6 +377,99 @@ typedef struct xlog_in_core {
 } 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;
+        sv_t                    xc_commit_wait;
+};
+
+/*
+ * The amount of log space we should the CIL to aggregate is difficult to size.
+ * Whatever we chose we have to make 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 basically make up arbitrary limits for the
+ * checkpoint size so long as they don't violate any other size rules.  Hence
+ * the initial maximum size for the checkpoint transaction will be set to a
+ * quarter of the log or 8MB, which ever is smaller. 8MB is an arbitrary limit
+ * right now based on the latency of writing out a large amount of data through
+ * the circular iclog buffers.
+ */
+
+#define XLOG_CIL_SPACE_LIMIT(log)       \
+        (min((log->l_logsize >> 2), (8 * 1024 * 1024)))
+
+/*
  * 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
@@ -388,6 +479,7 @@ 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 */
@@ -438,14 +530,17 @@ typedef struct log {
 
 #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;
+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)
@@ -455,6 +550,21 @@ xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t 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);
+
+/*
+ * 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);
+
+int     xlog_cil_push(struct log *log, int push_now);
+xfs_lsn_t xlog_cil_push_lsn(struct log *log, xfs_lsn_t push_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.