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Diffstat (limited to 'fs/jbd2/checkpoint.c')
-rw-r--r--fs/jbd2/checkpoint.c277
1 files changed, 94 insertions, 183 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 51bd38da21cd..9ec91017a7f3 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -27,7 +27,7 @@
*
* Called with j_list_lock held.
*/
-static inline void __buffer_unlink_first(struct journal_head *jh)
+static inline void __buffer_unlink(struct journal_head *jh)
{
transaction_t *transaction = jh->b_cp_transaction;
@@ -41,45 +41,6 @@ static inline void __buffer_unlink_first(struct journal_head *jh)
}
/*
- * Unlink a buffer from a transaction checkpoint(io) list.
- *
- * Called with j_list_lock held.
- */
-static inline void __buffer_unlink(struct journal_head *jh)
-{
- transaction_t *transaction = jh->b_cp_transaction;
-
- __buffer_unlink_first(jh);
- if (transaction->t_checkpoint_io_list == jh) {
- transaction->t_checkpoint_io_list = jh->b_cpnext;
- if (transaction->t_checkpoint_io_list == jh)
- transaction->t_checkpoint_io_list = NULL;
- }
-}
-
-/*
- * Move a buffer from the checkpoint list to the checkpoint io list
- *
- * Called with j_list_lock held
- */
-static inline void __buffer_relink_io(struct journal_head *jh)
-{
- transaction_t *transaction = jh->b_cp_transaction;
-
- __buffer_unlink_first(jh);
-
- if (!transaction->t_checkpoint_io_list) {
- jh->b_cpnext = jh->b_cpprev = jh;
- } else {
- jh->b_cpnext = transaction->t_checkpoint_io_list;
- jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev;
- jh->b_cpprev->b_cpnext = jh;
- jh->b_cpnext->b_cpprev = jh;
- }
- transaction->t_checkpoint_io_list = jh;
-}
-
-/*
* Check a checkpoint buffer could be release or not.
*
* Requires j_list_lock
@@ -183,6 +144,7 @@ __flush_batch(journal_t *journal, int *batch_count)
struct buffer_head *bh = journal->j_chkpt_bhs[i];
BUFFER_TRACE(bh, "brelse");
__brelse(bh);
+ journal->j_chkpt_bhs[i] = NULL;
}
*batch_count = 0;
}
@@ -242,15 +204,6 @@ restart:
jh = transaction->t_checkpoint_list;
bh = jh2bh(jh);
- if (buffer_locked(bh)) {
- get_bh(bh);
- spin_unlock(&journal->j_list_lock);
- wait_on_buffer(bh);
- /* the journal_head may have gone by now */
- BUFFER_TRACE(bh, "brelse");
- __brelse(bh);
- goto retry;
- }
if (jh->b_transaction != NULL) {
transaction_t *t = jh->b_transaction;
tid_t tid = t->t_tid;
@@ -285,30 +238,50 @@ restart:
spin_lock(&journal->j_list_lock);
goto restart;
}
- if (!buffer_dirty(bh)) {
+ if (!trylock_buffer(bh)) {
+ /*
+ * The buffer is locked, it may be writing back, or
+ * flushing out in the last couple of cycles, or
+ * re-adding into a new transaction, need to check
+ * it again until it's unlocked.
+ */
+ get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
+ wait_on_buffer(bh);
+ /* the journal_head may have gone by now */
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ goto retry;
+ } else if (!buffer_dirty(bh)) {
+ unlock_buffer(bh);
BUFFER_TRACE(bh, "remove from checkpoint");
- if (__jbd2_journal_remove_checkpoint(jh))
- /* The transaction was released; we're done */
+ /*
+ * If the transaction was released or the checkpoint
+ * list was empty, we're done.
+ */
+ if (__jbd2_journal_remove_checkpoint(jh) ||
+ !transaction->t_checkpoint_list)
goto out;
- continue;
+ } else {
+ unlock_buffer(bh);
+ /*
+ * We are about to write the buffer, it could be
+ * raced by some other transaction shrink or buffer
+ * re-log logic once we release the j_list_lock,
+ * leave it on the checkpoint list and check status
+ * again to make sure it's clean.
+ */
+ BUFFER_TRACE(bh, "queue");
+ get_bh(bh);
+ J_ASSERT_BH(bh, !buffer_jwrite(bh));
+ journal->j_chkpt_bhs[batch_count++] = bh;
+ transaction->t_chp_stats.cs_written++;
+ transaction->t_checkpoint_list = jh->b_cpnext;
}
- /*
- * Important: we are about to write the buffer, and
- * possibly block, while still holding the journal
- * lock. We cannot afford to let the transaction
- * logic start messing around with this buffer before
- * we write it to disk, as that would break
- * recoverability.
- */
- BUFFER_TRACE(bh, "queue");
- get_bh(bh);
- J_ASSERT_BH(bh, !buffer_jwrite(bh));
- journal->j_chkpt_bhs[batch_count++] = bh;
- __buffer_relink_io(jh);
- transaction->t_chp_stats.cs_written++;
+
if ((batch_count == JBD2_NR_BATCH) ||
- need_resched() ||
- spin_needbreak(&journal->j_list_lock))
+ need_resched() || spin_needbreak(&journal->j_list_lock) ||
+ jh2bh(transaction->t_checkpoint_list) == journal->j_chkpt_bhs[0])
goto unlock_and_flush;
}
@@ -322,38 +295,6 @@ restart:
goto restart;
}
- /*
- * Now we issued all of the transaction's buffers, let's deal
- * with the buffers that are out for I/O.
- */
-restart2:
- /* Did somebody clean up the transaction in the meanwhile? */
- if (journal->j_checkpoint_transactions != transaction ||
- transaction->t_tid != this_tid)
- goto out;
-
- while (transaction->t_checkpoint_io_list) {
- jh = transaction->t_checkpoint_io_list;
- bh = jh2bh(jh);
- if (buffer_locked(bh)) {
- get_bh(bh);
- spin_unlock(&journal->j_list_lock);
- wait_on_buffer(bh);
- /* the journal_head may have gone by now */
- BUFFER_TRACE(bh, "brelse");
- __brelse(bh);
- spin_lock(&journal->j_list_lock);
- goto restart2;
- }
-
- /*
- * Now in whatever state the buffer currently is, we
- * know that it has been written out and so we can
- * drop it from the list
- */
- if (__jbd2_journal_remove_checkpoint(jh))
- break;
- }
out:
spin_unlock(&journal->j_list_lock);
result = jbd2_cleanup_journal_tail(journal);
@@ -409,49 +350,9 @@ int jbd2_cleanup_journal_tail(journal_t *journal)
/* Checkpoint list management */
/*
- * journal_clean_one_cp_list
- *
- * Find all the written-back checkpoint buffers in the given list and
- * release them. If 'destroy' is set, clean all buffers unconditionally.
- *
- * Called with j_list_lock held.
- * Returns 1 if we freed the transaction, 0 otherwise.
- */
-static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
-{
- struct journal_head *last_jh;
- struct journal_head *next_jh = jh;
-
- if (!jh)
- return 0;
-
- last_jh = jh->b_cpprev;
- do {
- jh = next_jh;
- next_jh = jh->b_cpnext;
-
- if (!destroy && __cp_buffer_busy(jh))
- return 0;
-
- if (__jbd2_journal_remove_checkpoint(jh))
- return 1;
- /*
- * This function only frees up some memory
- * if possible so we dont have an obligation
- * to finish processing. Bail out if preemption
- * requested:
- */
- if (need_resched())
- return 0;
- } while (jh != last_jh);
-
- return 0;
-}
-
-/*
* journal_shrink_one_cp_list
*
- * Find 'nr_to_scan' written-back checkpoint buffers in the given list
+ * Find all the written-back checkpoint buffers in the given list
* and try to release them. If the whole transaction is released, set
* the 'released' parameter. Return the number of released checkpointed
* buffers.
@@ -459,15 +360,15 @@ static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
* Called with j_list_lock held.
*/
static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
- unsigned long *nr_to_scan,
- bool *released)
+ bool destroy, bool *released)
{
struct journal_head *last_jh;
struct journal_head *next_jh = jh;
unsigned long nr_freed = 0;
int ret;
- if (!jh || *nr_to_scan == 0)
+ *released = false;
+ if (!jh)
return 0;
last_jh = jh->b_cpprev;
@@ -475,12 +376,15 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
jh = next_jh;
next_jh = jh->b_cpnext;
- (*nr_to_scan)--;
- if (__cp_buffer_busy(jh))
- continue;
+ if (destroy) {
+ ret = __jbd2_journal_remove_checkpoint(jh);
+ } else {
+ ret = jbd2_journal_try_remove_checkpoint(jh);
+ if (ret < 0)
+ continue;
+ }
nr_freed++;
- ret = __jbd2_journal_remove_checkpoint(jh);
if (ret) {
*released = true;
break;
@@ -488,7 +392,7 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
if (need_resched())
break;
- } while (jh != last_jh && *nr_to_scan);
+ } while (jh != last_jh);
return nr_freed;
}
@@ -506,11 +410,11 @@ unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal,
unsigned long *nr_to_scan)
{
transaction_t *transaction, *last_transaction, *next_transaction;
- bool released;
+ bool __maybe_unused released;
tid_t first_tid = 0, last_tid = 0, next_tid = 0;
tid_t tid = 0;
unsigned long nr_freed = 0;
- unsigned long nr_scanned = *nr_to_scan;
+ unsigned long freed;
again:
spin_lock(&journal->j_list_lock);
@@ -539,19 +443,11 @@ again:
transaction = next_transaction;
next_transaction = transaction->t_cpnext;
tid = transaction->t_tid;
- released = false;
-
- nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_list,
- nr_to_scan, &released);
- if (*nr_to_scan == 0)
- break;
- if (need_resched() || spin_needbreak(&journal->j_list_lock))
- break;
- if (released)
- continue;
- nr_freed += journal_shrink_one_cp_list(transaction->t_checkpoint_io_list,
- nr_to_scan, &released);
+ freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list,
+ false, &released);
+ nr_freed += freed;
+ (*nr_to_scan) -= min(*nr_to_scan, freed);
if (*nr_to_scan == 0)
break;
if (need_resched() || spin_needbreak(&journal->j_list_lock))
@@ -572,9 +468,8 @@ again:
if (*nr_to_scan && next_tid)
goto again;
out:
- nr_scanned -= *nr_to_scan;
trace_jbd2_shrink_checkpoint_list(journal, first_tid, tid, last_tid,
- nr_freed, nr_scanned, next_tid);
+ nr_freed, next_tid);
return nr_freed;
}
@@ -590,7 +485,7 @@ out:
void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
{
transaction_t *transaction, *last_transaction, *next_transaction;
- int ret;
+ bool released;
transaction = journal->j_checkpoint_transactions;
if (!transaction)
@@ -601,8 +496,8 @@ void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
do {
transaction = next_transaction;
next_transaction = transaction->t_cpnext;
- ret = journal_clean_one_cp_list(transaction->t_checkpoint_list,
- destroy);
+ journal_shrink_one_cp_list(transaction->t_checkpoint_list,
+ destroy, &released);
/*
* This function only frees up some memory if possible so we
* dont have an obligation to finish processing. Bail out if
@@ -610,23 +505,12 @@ void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
*/
if (need_resched())
return;
- if (ret)
- continue;
- /*
- * It is essential that we are as careful as in the case of
- * t_checkpoint_list with removing the buffer from the list as
- * we can possibly see not yet submitted buffers on io_list
- */
- ret = journal_clean_one_cp_list(transaction->
- t_checkpoint_io_list, destroy);
- if (need_resched())
- return;
/*
* Stop scanning if we couldn't free the transaction. This
* avoids pointless scanning of transactions which still
* weren't checkpointed.
*/
- if (!ret)
+ if (!released)
return;
} while (transaction != last_transaction);
}
@@ -705,7 +589,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
jbd2_journal_put_journal_head(jh);
/* Is this transaction empty? */
- if (transaction->t_checkpoint_list || transaction->t_checkpoint_io_list)
+ if (transaction->t_checkpoint_list)
return 0;
/*
@@ -737,6 +621,34 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
}
/*
+ * Check the checkpoint buffer and try to remove it from the checkpoint
+ * list if it's clean. Returns -EBUSY if it is not clean, returns 1 if
+ * it frees the transaction, 0 otherwise.
+ *
+ * This function is called with j_list_lock held.
+ */
+int jbd2_journal_try_remove_checkpoint(struct journal_head *jh)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ if (!trylock_buffer(bh))
+ return -EBUSY;
+ if (buffer_dirty(bh)) {
+ unlock_buffer(bh);
+ return -EBUSY;
+ }
+ unlock_buffer(bh);
+
+ /*
+ * Buffer is clean and the IO has finished (we held the buffer
+ * lock) so the checkpoint is done. We can safely remove the
+ * buffer from this transaction.
+ */
+ JBUFFER_TRACE(jh, "remove from checkpoint list");
+ return __jbd2_journal_remove_checkpoint(jh);
+}
+
+/*
* journal_insert_checkpoint: put a committed buffer onto a checkpoint
* list so that we know when it is safe to clean the transaction out of
* the log.
@@ -797,7 +709,6 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
J_ASSERT(transaction->t_forget == NULL);
J_ASSERT(transaction->t_shadow_list == NULL);
J_ASSERT(transaction->t_checkpoint_list == NULL);
- J_ASSERT(transaction->t_checkpoint_io_list == NULL);
J_ASSERT(atomic_read(&transaction->t_updates) == 0);
J_ASSERT(journal->j_committing_transaction != transaction);
J_ASSERT(journal->j_running_transaction != transaction);