diff options
Diffstat (limited to 'fs/jbd2/checkpoint.c')
| -rw-r--r-- | fs/jbd2/checkpoint.c | 342 |
1 files changed, 126 insertions, 216 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 51bd38da21cd..de89c5bef607 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; @@ -41,57 +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 - */ -static inline bool __cp_buffer_busy(struct journal_head *jh) -{ - struct buffer_head *bh = jh2bh(jh); - - return (jh->b_transaction || buffer_locked(bh) || buffer_dirty(bh)); -} - -/* * __jbd2_log_wait_for_space: wait until there is space in the journal. * * Called under j-state_lock *only*. It will be unlocked if we have to wait @@ -130,17 +79,23 @@ __releases(&journal->j_state_lock) if (space_left < nblocks) { int chkpt = journal->j_checkpoint_transactions != NULL; tid_t tid = 0; + bool has_transaction = false; - if (journal->j_committing_transaction) + if (journal->j_committing_transaction) { tid = journal->j_committing_transaction->t_tid; + has_transaction = true; + } spin_unlock(&journal->j_list_lock); write_unlock(&journal->j_state_lock); if (chkpt) { jbd2_log_do_checkpoint(journal); - } else if (jbd2_cleanup_journal_tail(journal) == 0) { - /* We were able to recover space; yay! */ + } else if (jbd2_cleanup_journal_tail(journal) <= 0) { + /* + * We were able to recover space or the + * journal was aborted due to an error. + */ ; - } else if (tid) { + } else if (has_transaction) { /* * jbd2_journal_commit_transaction() may want * to take the checkpoint_mutex if JBD2_FLUSHED @@ -158,7 +113,7 @@ __releases(&journal->j_state_lock) "journal space in %s\n", __func__, journal->j_devname); WARN_ON(1); - jbd2_journal_abort(journal, -EIO); + jbd2_journal_abort(journal, -ENOSPC); } write_lock(&journal->j_state_lock); } else { @@ -176,13 +131,14 @@ __flush_batch(journal_t *journal, int *batch_count) blk_start_plug(&plug); for (i = 0; i < *batch_count; i++) - write_dirty_buffer(journal->j_chkpt_bhs[i], REQ_SYNC); + write_dirty_buffer(journal->j_chkpt_bhs[i], JBD2_JOURNAL_REQ_FLAGS); blk_finish_plug(&plug); for (i = 0; i < *batch_count; i++) { 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 +198,6 @@ 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 +232,50 @@ 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; } @@ -318,42 +285,11 @@ restart: retry: if (batch_count) __flush_batch(journal, &batch_count); + cond_resched(); spin_lock(&journal->j_list_lock); 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 +345,9 @@ 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. @@ -459,7 +355,7 @@ 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, + enum jbd2_shrink_type type, bool *released) { struct journal_head *last_jh; @@ -467,7 +363,8 @@ static unsigned long journal_shrink_one_cp_list(struct journal_head *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 +372,18 @@ 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 (type == JBD2_SHRINK_DESTROY) { + ret = __jbd2_journal_remove_checkpoint(jh); + } else { + ret = jbd2_journal_try_remove_checkpoint(jh); + if (ret < 0) { + if (type == JBD2_SHRINK_BUSY_SKIP) + continue; + break; + } + } nr_freed++; - ret = __jbd2_journal_remove_checkpoint(jh); if (ret) { *released = true; break; @@ -488,7 +391,7 @@ 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 +409,12 @@ 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; + bool first_set = false; again: spin_lock(&journal->j_list_lock); @@ -530,8 +434,10 @@ again: else transaction = journal->j_checkpoint_transactions; - if (!first_tid) + if (!first_set) { first_tid = transaction->t_tid; + first_set = true; + } last_transaction = journal->j_checkpoint_transactions->t_cpprev; next_transaction = transaction; last_tid = last_transaction->t_tid; @@ -539,19 +445,11 @@ 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, + JBD2_SHRINK_BUSY_SKIP, &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)) @@ -569,12 +467,11 @@ again: spin_unlock(&journal->j_list_lock); cond_resched(); - if (*nr_to_scan && next_tid) + if (*nr_to_scan && journal->j_shrink_transaction) 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; } @@ -583,14 +480,20 @@ out: * journal_clean_checkpoint_list * * Find all the written-back checkpoint buffers in the journal and release them. - * If 'destroy' is set, release all buffers unconditionally. + * If 'type' is JBD2_SHRINK_DESTROY, release all buffers unconditionally. If + * 'type' is JBD2_SHRINK_BUSY_STOP, will stop release buffers if encounters a + * busy buffer. To avoid wasting CPU cycles scanning the buffer list in some + * cases, don't pass JBD2_SHRINK_BUSY_SKIP 'type' for this function. * * Called with j_list_lock held. */ -void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) +void __jbd2_journal_clean_checkpoint_list(journal_t *journal, + enum jbd2_shrink_type type) { transaction_t *transaction, *last_transaction, *next_transaction; - int ret; + bool released; + + WARN_ON_ONCE(type == JBD2_SHRINK_BUSY_SKIP); transaction = journal->j_checkpoint_transactions; if (!transaction) @@ -601,8 +504,8 @@ 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, + type, &released); /* * This function only frees up some memory if possible so we * dont have an obligation to finish processing. Bail out if @@ -610,23 +513,12 @@ 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); } @@ -647,7 +539,7 @@ void jbd2_journal_destroy_checkpoint(journal_t *journal) spin_unlock(&journal->j_list_lock); break; } - __jbd2_journal_clean_checkpoint_list(journal, true); + __jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_DESTROY); spin_unlock(&journal->j_list_lock); cond_resched(); } @@ -676,7 +568,6 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh) struct transaction_chp_stats_s *stats; transaction_t *transaction; journal_t *journal; - struct buffer_head *bh = jh2bh(jh); JBUFFER_TRACE(jh, "entry"); @@ -689,23 +580,13 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh) JBUFFER_TRACE(jh, "removing from transaction"); - /* - * If we have failed to write the buffer out to disk, the filesystem - * may become inconsistent. We cannot abort the journal here since - * we hold j_list_lock and we have to be careful about races with - * jbd2_journal_destroy(). So mark the writeback IO error in the - * journal here and we abort the journal later from a better context. - */ - if (buffer_write_io_error(bh)) - set_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags); - __buffer_unlink(jh); jh->b_cp_transaction = NULL; percpu_counter_dec(&journal->j_checkpoint_jh_count); 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 +618,36 @@ 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 (jh->b_transaction) + return -EBUSY; + 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 +708,6 @@ 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); |