With the recent changes we never re-used busy extents. Remove all handling
of them and replace them with asserts. This also effectively reverts
commit 955833cf2ad0aa39b336e853cad212d867199984
"xfs: make the log ticket ID available outside the log infrastructure"
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: xfs/fs/xfs/xfs_ag.h
===================================================================
--- xfs.orig/fs/xfs/xfs_ag.h 2011-01-18 13:06:47.588254235 +0100
+++ xfs/fs/xfs/xfs_ag.h 2011-01-18 13:07:05.608012022 +0100
@@ -187,7 +187,6 @@ struct xfs_busy_extent {
xfs_agnumber_t agno;
xfs_agblock_t bno;
xfs_extlen_t length;
- xlog_tid_t tid; /* transaction that created this */
int flags;
};
Index: xfs/fs/xfs/xfs_alloc.c
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc.c 2011-01-18 13:06:47.595254654 +0100
+++ xfs/fs/xfs/xfs_alloc.c 2011-01-18 13:08:34.000000000 +0100
@@ -2518,83 +2518,7 @@ error0:
/*
* Insert a new extent into the busy tree.
*
- * The busy extent tree is indexed by the start block of the busy extent.
- * there can be multiple overlapping ranges in the busy extent tree but only
- * ever one entry at a given start block. The reason for this is that
- * multi-block extents can be freed, then smaller chunks of that extent
- * allocated and freed again before the first transaction commit is on disk.
- * If the exact same start block is freed a second time, we have to wait for
- * that busy extent to pass out of the tree before the new extent is inserted.
- * There are two main cases we have to handle here.
- *
- * The first case is a transaction that triggers a "free - allocate - free"
- * cycle. This can occur during btree manipulations as a btree block is freed
- * to the freelist, then allocated from the free list, then freed again. In
- * this case, the second extxpnet free is what triggers the duplicate and as
- * such the transaction IDs should match. Because the extent was allocated in
- * this transaction, the transaction must be marked as synchronous. This is
- * true for all cases where the free/alloc/free occurs in the one transaction,
- * hence the addition of the ASSERT(tp->t_flags & XFS_TRANS_SYNC) to this case.
- * This serves to catch violations of the second case quite effectively.
- *
- * The second case is where the free/alloc/free occur in different
- * transactions. In this case, the thread freeing the extent the second time
- * can't mark the extent busy immediately because it is already tracked in a
- * transaction that may be committing. When the log commit for the existing
- * busy extent completes, the busy extent will be removed from the tree. If we
- * allow the second busy insert to continue using that busy extent structure,
- * it can be freed before this transaction is safely in the log. Hence our
- * only option in this case is to force the log to remove the existing busy
- * extent from the list before we insert the new one with the current
- * transaction ID.
- *
- * The problem we are trying to avoid in the free-alloc-free in separate
- * transactions is most easily described with a timeline:
- *
- * Thread 1 Thread 2 Thread 3 xfslogd
- * xact alloc
- * free X
- * mark busy
- * commit xact
- * free xact
- * xact alloc
- * alloc X
- * busy search
- * mark xact sync
- * commit xact
- * free xact
- * force log
- * checkpoint starts
- * ....
- * xact alloc
- * free X
- * mark busy
- * finds match
- * *** KABOOM! ***
- * ....
- * log IO completes
- * unbusy X
- * checkpoint completes
- *
- * By issuing a log force in thread 3 @ "KABOOM", the thread will block until
- * the checkpoint completes, and the busy extent it matched will have been
- * removed from the tree when it is woken. Hence it can then continue safely.
- *
- * However, to ensure this matching process is robust, we need to use the
- * transaction ID for identifying transaction, as delayed logging results in
- * the busy extent and transaction lifecycles being different. i.e. the busy
- * extent is active for a lot longer than the transaction. Hence the
- * transaction structure can be freed and reallocated, then mark the same
- * extent busy again in the new transaction. In this case the new transaction
- * will have a different tid but can have the same address, and hence we need
- * to check against the tid.
- *
- * Future: for delayed logging, we could avoid the log force if the extent was
- * first freed in the current checkpoint sequence. This, however, requires the
- * ability to pin the current checkpoint in memory until this transaction
- * commits to ensure that both the original free and the current one combine
- * logically into the one checkpoint. If the checkpoint sequences are
- * different, however, we still need to wait on a log force.
+ * The busy extent tree is indexed by the start block of the busy extent
*/
STATIC void
xfs_alloc_busy_insert(
@@ -2609,8 +2533,6 @@ xfs_alloc_busy_insert(
struct xfs_perag *pag;
struct rb_node **rbp;
struct rb_node *parent;
- int match;
-
new = kmem_zalloc(sizeof(struct xfs_busy_extent), KM_MAYFAIL);
if (!new) {
@@ -2628,74 +2550,35 @@ xfs_alloc_busy_insert(
new->bno = bno;
new->length = len;
new->flags = flags;
- new->tid = xfs_log_get_trans_ident(tp);
-
INIT_LIST_HEAD(&new->list);
/* trace before insert to be able to see failed inserts */
trace_xfs_alloc_busy(tp, agno, bno, len, 0);
pag = xfs_perag_get(tp->t_mountp, new->agno);
-restart:
spin_lock(&pag->pagb_lock);
rbp = &pag->pagb_tree.rb_node;
parent = NULL;
- busyp = NULL;
- match = 0;
- while (*rbp && match >= 0) {
+ while (*rbp) {
parent = *rbp;
busyp = rb_entry(parent, struct xfs_busy_extent, rb_node);
if (new->bno < busyp->bno) {
- /* may overlap, but exact start block is lower */
+ ASSERT(new->bno + new->length <= busyp->bno);
rbp = &(*rbp)->rb_left;
- if (new->bno + new->length > busyp->bno)
- match = busyp->tid == new->tid ? 1 : -1;
- } else if (new->bno > busyp->bno) {
- /* may overlap, but exact start block is higher */
- rbp = &(*rbp)->rb_right;
- if (bno < busyp->bno + busyp->length)
- match = busyp->tid == new->tid ? 1 : -1;
} else {
- match = busyp->tid == new->tid ? 1 : -1;
- break;
+ ASSERT(new->bno > busyp->bno);
+ ASSERT(bno >= busyp->bno + busyp->length);
+ rbp = &(*rbp)->rb_right;
}
}
- if (match < 0) {
- /* overlap marked busy in different transaction */
- spin_unlock(&pag->pagb_lock);
- xfs_log_force(tp->t_mountp, XFS_LOG_SYNC);
- goto restart;
- }
- if (match > 0) {
- /*
- * overlap marked busy in same transaction. Update if exact
- * start block match, otherwise combine the busy extents into
- * a single range.
- */
- if (busyp->bno == new->bno) {
- busyp->length = max(busyp->length, new->length);
- spin_unlock(&pag->pagb_lock);
- ASSERT(tp->t_flags & XFS_TRANS_SYNC);
- xfs_perag_put(pag);
- kmem_free(new);
- return;
- }
- rb_erase(&busyp->rb_node, &pag->pagb_tree);
- new->length = max(busyp->bno + busyp->length,
- new->bno + new->length) -
- min(busyp->bno, new->bno);
- new->bno = min(busyp->bno, new->bno);
- } else
- busyp = NULL;
rb_link_node(&new->rb_node, parent, rbp);
rb_insert_color(&new->rb_node, &pag->pagb_tree);
-
list_add(&new->list, &tp->t_busy);
+
spin_unlock(&pag->pagb_lock);
xfs_perag_put(pag);
- kmem_free(busyp);
}
/*
Index: xfs/fs/xfs/xfs_log.c
===================================================================
--- xfs.orig/fs/xfs/xfs_log.c 2011-01-18 13:06:47.612254724 +0100
+++ xfs/fs/xfs/xfs_log.c 2011-01-18 13:07:05.929013420 +0100
@@ -3256,13 +3256,6 @@ xfs_log_ticket_get(
return ticket;
}
-xlog_tid_t
-xfs_log_get_trans_ident(
- struct xfs_trans *tp)
-{
- return tp->t_ticket->t_tid;
-}
-
/*
* Allocate and initialise a new log ticket.
*/
Index: xfs/fs/xfs/xfs_log.h
===================================================================
--- xfs.orig/fs/xfs/xfs_log.h 2011-01-18 13:06:47.618254514 +0100
+++ xfs/fs/xfs/xfs_log.h 2011-01-18 13:07:05.936017889 +0100
@@ -189,8 +189,6 @@ void xlog_iodone(struct xfs_buf *);
struct xlog_ticket *xfs_log_ticket_get(struct xlog_ticket *ticket);
void xfs_log_ticket_put(struct xlog_ticket *ticket);
-xlog_tid_t xfs_log_get_trans_ident(struct xfs_trans *tp);
-
int xfs_log_commit_cil(struct xfs_mount *mp, struct xfs_trans *tp,
struct xfs_log_vec *log_vector,
xfs_lsn_t *commit_lsn, int flags);
Index: xfs/fs/xfs/xfs_log_priv.h
===================================================================
--- xfs.orig/fs/xfs/xfs_log_priv.h 2011-01-18 13:06:47.625253956 +0100
+++ xfs/fs/xfs/xfs_log_priv.h 2011-01-18 13:07:05.951006924 +0100
@@ -148,6 +148,8 @@ static inline uint xlog_get_client_id(__
#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__
/*
Index: xfs/fs/xfs/xfs_types.h
===================================================================
--- xfs.orig/fs/xfs/xfs_types.h 2011-01-18 13:06:47.645254026 +0100
+++ xfs/fs/xfs/xfs_types.h 2011-01-18 13:07:05.958005458 +0100
@@ -73,8 +73,6 @@ typedef __int32_t xfs_tid_t; /* transact
typedef __uint32_t xfs_dablk_t; /* dir/attr block number (in file) */
typedef __uint32_t xfs_dahash_t; /* dir/attr hash value */
-typedef __uint32_t xlog_tid_t; /* transaction ID type */
-
/*
* These types are 64 bits on disk but are either 32 or 64 bits in memory.
* Disk based types:
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