xfs: use struct list_head for the buf cancel table

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

3 files changed, 65 insertions, 111 deletions

diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 0e2ed43f16c..b6ecd2061e7 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -105,17 +105,6 @@ typedef struct xfs_buf_log_item {
         xfs_buf_log_format_t    bli_format;     /* in-log header */
 } xfs_buf_log_item_t;
 
-/*
- * This structure is used during recovery to record the buf log
- * items which have been canceled and should not be replayed.
- */
-typedef struct xfs_buf_cancel {
-        xfs_daddr_t             bc_blkno;
-        uint                    bc_len;
-        int                     bc_refcount;
-        struct xfs_buf_cancel   *bc_next;
-} xfs_buf_cancel_t;
-
 void    xfs_buf_item_init(struct xfs_buf *, struct xfs_mount *);
 void    xfs_buf_item_relse(struct xfs_buf *);
 void    xfs_buf_item_log(xfs_buf_log_item_t *, uint, uint);
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index edcdfe01617..c1ce505313e 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -21,7 +21,6 @@
 struct xfs_buf;
 struct log;
 struct xlog_ticket;
-struct xfs_buf_cancel;
 struct xfs_mount;
 
 /*
@@ -491,7 +490,7 @@ typedef struct log {
         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;
+        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) */
@@ -534,6 +533,9 @@ typedef struct log {
 
 } 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 */
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index e51d93db1b0..960afd41315 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -53,6 +53,17 @@ STATIC void	xlog_recover_check_summary(xlog_t *);
 #endif
 
 /*
+ * This structure is used during recovery to record the buf log items which
+ * have been canceled and should not be replayed.
+ */
+struct xfs_buf_cancel {
+        xfs_daddr_t             bc_blkno;
+        uint                    bc_len;
+        int                     bc_refcount;
+        struct list_head        bc_list;
+};
+
+/*
  * Sector aligned buffer routines for buffer create/read/write/access
  */
 
@@ -1607,15 +1618,11 @@ xlog_recover_reorder_trans(
  */
 STATIC void
 xlog_recover_do_buffer_pass1(
-        xlog_t                  *log,
+        struct log              *log,
         xfs_buf_log_format_t    *buf_f)
 {
-        xfs_buf_cancel_t        *bcp;
-        xfs_buf_cancel_t        *nextp;
-        xfs_buf_cancel_t        *prevp;
-        xfs_buf_cancel_t        **bucket;
-        xfs_daddr_t             blkno = buf_f->blf_blkno;
-        uint                    len = buf_f->blf_len;
+        struct list_head        *bucket;
+        struct xfs_buf_cancel   *bcp;
 
         /*
          * If this isn't a cancel buffer item, then just return.
@@ -1626,51 +1633,25 @@ xlog_recover_do_buffer_pass1(
         }
 
         /*
-         * Insert an xfs_buf_cancel record into the hash table of
-         * them.  If there is already an identical record, bump
-         * its reference count.
-         */
-        bucket = &log->l_buf_cancel_table[(__uint64_t)blkno %
-                                          XLOG_BC_TABLE_SIZE];
-        /*
-         * If the hash bucket is empty then just insert a new record into
-         * the bucket.
-         */
-        if (*bucket == NULL) {
-                bcp = (xfs_buf_cancel_t *)kmem_alloc(sizeof(xfs_buf_cancel_t),
-                                                     KM_SLEEP);
-                bcp->bc_blkno = blkno;
-                bcp->bc_len = len;
-                bcp->bc_refcount = 1;
-                bcp->bc_next = NULL;
-                *bucket = bcp;
-                return;
-        }
-
-        /*
-         * The hash bucket is not empty, so search for duplicates of our
-         * record.  If we find one them just bump its refcount.  If not
-         * then add us at the end of the list.
+         * Insert an xfs_buf_cancel record into the hash table of them.
+         * If there is already an identical record, bump its reference count.
          */
-        prevp = NULL;
-        nextp = *bucket;
-        while (nextp != NULL) {
-                if (nextp->bc_blkno == blkno && nextp->bc_len == len) {
-                        nextp->bc_refcount++;
+        bucket = XLOG_BUF_CANCEL_BUCKET(log, buf_f->blf_blkno);
+        list_for_each_entry(bcp, bucket, bc_list) {
+                if (bcp->bc_blkno == buf_f->blf_blkno &&
+                    bcp->bc_len == buf_f->blf_len) {
+                        bcp->bc_refcount++;
                         trace_xfs_log_recover_buf_cancel_ref_inc(log, buf_f);
                         return;
                 }
-                prevp = nextp;
-                nextp = nextp->bc_next;
-        }
-        ASSERT(prevp != NULL);
-        bcp = (xfs_buf_cancel_t *)kmem_alloc(sizeof(xfs_buf_cancel_t),
-                                             KM_SLEEP);
-        bcp->bc_blkno = blkno;
-        bcp->bc_len = len;
+        }
+
+        bcp = kmem_alloc(sizeof(struct xfs_buf_cancel), KM_SLEEP);
+        bcp->bc_blkno = buf_f->blf_blkno;
+        bcp->bc_len = buf_f->blf_len;
         bcp->bc_refcount = 1;
-        bcp->bc_next = NULL;
-        prevp->bc_next = bcp;
+        list_add_tail(&bcp->bc_list, bucket);
+
         trace_xfs_log_recover_buf_cancel_add(log, buf_f);
 }
 
@@ -1689,14 +1670,13 @@ xlog_recover_do_buffer_pass1(
  */
 STATIC int
 xlog_check_buffer_cancelled(
-        xlog_t                  *log,
+        struct log              *log,
         xfs_daddr_t             blkno,
         uint                    len,
         ushort                  flags)
 {
-        xfs_buf_cancel_t        *bcp;
-        xfs_buf_cancel_t        *prevp;
-        xfs_buf_cancel_t        **bucket;
+        struct list_head        *bucket;
+        struct xfs_buf_cancel   *bcp;
 
         if (log->l_buf_cancel_table == NULL) {
                 /*
@@ -1707,55 +1687,36 @@ xlog_check_buffer_cancelled(
                 return 0;
         }
 
-        bucket = &log->l_buf_cancel_table[(__uint64_t)blkno %
-                                          XLOG_BC_TABLE_SIZE];
-        bcp = *bucket;
-        if (bcp == NULL) {
-                /*
-                 * There is no corresponding entry in the table built
-                 * in pass one, so this buffer has not been cancelled.
-                 */
-                ASSERT(!(flags & XFS_BLF_CANCEL));
-                return 0;
-        }
-
         /*
-         * Search for an entry in the buffer cancel table that
-         * matches our buffer.
+         * Search for an entry in the  cancel table that matches our buffer.
          */
-        prevp = NULL;
-        while (bcp != NULL) {
-                if (bcp->bc_blkno == blkno && bcp->bc_len == len) {
-                        /*
-                         * We've go a match, so return 1 so that the
-                         * recovery of this buffer is cancelled.
-                         * If this buffer is actually a buffer cancel
-                         * log item, then decrement the refcount on the
-                         * one in the table and remove it if this is the
-                         * last reference.
-                         */
-                        if (flags & XFS_BLF_CANCEL) {
-                                bcp->bc_refcount--;
-                                if (bcp->bc_refcount == 0) {
-                                        if (prevp == NULL) {
-                                                *bucket = bcp->bc_next;
-                                        } else {
-                                                prevp->bc_next = bcp->bc_next;
-                                        }
-                                        kmem_free(bcp);
-                                }
-                        }
-                        return 1;
-                }
-                prevp = bcp;
-                bcp = bcp->bc_next;
+        bucket = XLOG_BUF_CANCEL_BUCKET(log, blkno);
+        list_for_each_entry(bcp, bucket, bc_list) {
+                if (bcp->bc_blkno == blkno && bcp->bc_len == len)
+                        goto found;
         }
+
         /*
-         * We didn't find a corresponding entry in the table, so
-         * return 0 so that the buffer is NOT cancelled.
+         * We didn't find a corresponding entry in the table, so return 0 so
+         * that the buffer is NOT cancelled.
          */
         ASSERT(!(flags & XFS_BLF_CANCEL));
         return 0;
+
+found:
+        /*
+         * We've go a match, so return 1 so that the recovery of this buffer
+         * is cancelled.  If this buffer is actually a buffer cancel log
+         * item, then decrement the refcount on the one in the table and
+         * remove it if this is the last reference.
+         */
+        if (flags & XFS_BLF_CANCEL) {
+                if (--bcp->bc_refcount == 0) {
+                        list_del(&bcp->bc_list);
+                        kmem_free(bcp);
+                }
+        }
+        return 1;
 }
 
 /*
@@ -3649,7 +3610,7 @@ xlog_do_log_recovery(
         xfs_daddr_t     head_blk,
         xfs_daddr_t     tail_blk)
 {
-        int             error;
+        int             error, i;
 
         ASSERT(head_blk != tail_blk);
 
@@ -3657,10 +3618,12 @@ xlog_do_log_recovery(
          * First do a pass to find all of the cancelled buf log items.
          * Store them in the buf_cancel_table for use in the second pass.
          */
-        log->l_buf_cancel_table =
-                (xfs_buf_cancel_t **)kmem_zalloc(XLOG_BC_TABLE_SIZE *
-                                                 sizeof(xfs_buf_cancel_t*),
+        log->l_buf_cancel_table = kmem_zalloc(XLOG_BC_TABLE_SIZE *
+                                                 sizeof(struct list_head),
                                                  KM_SLEEP);
+        for (i = 0; i < XLOG_BC_TABLE_SIZE; i++)
+                INIT_LIST_HEAD(&log->l_buf_cancel_table[i]);
+
         error = xlog_do_recovery_pass(log, head_blk, tail_blk,
                                       XLOG_RECOVER_PASS1);
         if (error != 0) {
@@ -3679,7 +3642,7 @@ xlog_do_log_recovery(
                 int     i;
 
                 for (i = 0; i < XLOG_BC_TABLE_SIZE; i++)
-                        ASSERT(log->l_buf_cancel_table[i] == NULL);
+                        ASSERT(list_empty(&log->l_buf_cancel_table[i]));
         }
 #endif  /* DEBUG */