Merge commit 'v2.6.30' into for-2.6.31
[safe/jmp/linux-2.6] / fs / jbd / checkpoint.c
index a5432bb..61f32f3 100644 (file)
@@ -93,7 +93,8 @@ static int __try_to_free_cp_buf(struct journal_head *jh)
        int ret = 0;
        struct buffer_head *bh = jh2bh(jh);
 
-       if (jh->b_jlist == BJ_None && !buffer_locked(bh) && !buffer_dirty(bh)) {
+       if (jh->b_jlist == BJ_None && !buffer_locked(bh) &&
+           !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
                JBUFFER_TRACE(jh, "remove from checkpoint list");
                ret = __journal_remove_checkpoint(jh) + 1;
                jbd_unlock_bh_state(bh);
@@ -114,7 +115,7 @@ static int __try_to_free_cp_buf(struct journal_head *jh)
  */
 void __log_wait_for_space(journal_t *journal)
 {
-       int nblocks;
+       int nblocks, space_left;
        assert_spin_locked(&journal->j_state_lock);
 
        nblocks = jbd_space_needed(journal);
@@ -126,14 +127,46 @@ void __log_wait_for_space(journal_t *journal)
 
                /*
                 * Test again, another process may have checkpointed while we
-                * were waiting for the checkpoint lock
+                * were waiting for the checkpoint lock. If there are no
+                * transactions ready to be checkpointed, try to recover
+                * journal space by calling cleanup_journal_tail(), and if
+                * that doesn't work, by waiting for the currently committing
+                * transaction to complete.  If there is absolutely no way
+                * to make progress, this is either a BUG or corrupted
+                * filesystem, so abort the journal and leave a stack
+                * trace for forensic evidence.
                 */
                spin_lock(&journal->j_state_lock);
+               spin_lock(&journal->j_list_lock);
                nblocks = jbd_space_needed(journal);
-               if (__log_space_left(journal) < nblocks) {
+               space_left = __log_space_left(journal);
+               if (space_left < nblocks) {
+                       int chkpt = journal->j_checkpoint_transactions != NULL;
+                       tid_t tid = 0;
+
+                       if (journal->j_committing_transaction)
+                               tid = journal->j_committing_transaction->t_tid;
+                       spin_unlock(&journal->j_list_lock);
                        spin_unlock(&journal->j_state_lock);
-                       log_do_checkpoint(journal);
+                       if (chkpt) {
+                               log_do_checkpoint(journal);
+                       } else if (cleanup_journal_tail(journal) == 0) {
+                               /* We were able to recover space; yay! */
+                               ;
+                       } else if (tid) {
+                               log_wait_commit(journal, tid);
+                       } else {
+                               printk(KERN_ERR "%s: needed %d blocks and "
+                                      "only had %d space available\n",
+                                      __func__, nblocks, space_left);
+                               printk(KERN_ERR "%s: no way to get more "
+                                      "journal space\n", __func__);
+                               WARN_ON(1);
+                               journal_abort(journal, 0);
+                       }
                        spin_lock(&journal->j_state_lock);
+               } else {
+                       spin_unlock(&journal->j_list_lock);
                }
                mutex_unlock(&journal->j_checkpoint_mutex);
        }
@@ -160,21 +193,25 @@ static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh)
  * buffers. Note that we take the buffers in the opposite ordering
  * from the one in which they were submitted for IO.
  *
+ * Return 0 on success, and return <0 if some buffers have failed
+ * to be written out.
+ *
  * Called with j_list_lock held.
  */
-static void __wait_cp_io(journal_t *journal, transaction_t *transaction)
+static int __wait_cp_io(journal_t *journal, transaction_t *transaction)
 {
        struct journal_head *jh;
        struct buffer_head *bh;
        tid_t this_tid;
        int released = 0;
+       int ret = 0;
 
        this_tid = transaction->t_tid;
 restart:
        /* Did somebody clean up the transaction in the meanwhile? */
        if (journal->j_checkpoint_transactions != transaction ||
                        transaction->t_tid != this_tid)
-               return;
+               return ret;
        while (!released && transaction->t_checkpoint_io_list) {
                jh = transaction->t_checkpoint_io_list;
                bh = jh2bh(jh);
@@ -194,6 +231,9 @@ restart:
                        spin_lock(&journal->j_list_lock);
                        goto restart;
                }
+               if (unlikely(buffer_write_io_error(bh)))
+                       ret = -EIO;
+
                /*
                 * 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
@@ -203,6 +243,8 @@ restart:
                journal_remove_journal_head(bh);
                __brelse(bh);
        }
+
+       return ret;
 }
 
 #define NR_BATCH       64
@@ -226,7 +268,8 @@ __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count)
  * Try to flush one buffer from the checkpoint list to disk.
  *
  * Return 1 if something happened which requires us to abort the current
- * scan of the checkpoint list.
+ * scan of the checkpoint list.  Return <0 if the buffer has failed to
+ * be written out.
  *
  * Called with j_list_lock held and drops it if 1 is returned
  * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
@@ -256,6 +299,9 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
                log_wait_commit(journal, tid);
                ret = 1;
        } else if (!buffer_dirty(bh)) {
+               ret = 1;
+               if (unlikely(buffer_write_io_error(bh)))
+                       ret = -EIO;
                J_ASSERT_JH(jh, !buffer_jbddirty(bh));
                BUFFER_TRACE(bh, "remove from checkpoint");
                __journal_remove_checkpoint(jh);
@@ -263,7 +309,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
                jbd_unlock_bh_state(bh);
                journal_remove_journal_head(bh);
                __brelse(bh);
-               ret = 1;
        } else {
                /*
                 * Important: we are about to write the buffer, and
@@ -295,6 +340,7 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
  * to disk. We submit larger chunks of data at once.
  *
  * The journal should be locked before calling this function.
+ * Called with j_checkpoint_mutex held.
  */
 int log_do_checkpoint(journal_t *journal)
 {
@@ -318,6 +364,7 @@ int log_do_checkpoint(journal_t *journal)
         * OK, we need to start writing disk blocks.  Take one transaction
         * and write it.
         */
+       result = 0;
        spin_lock(&journal->j_list_lock);
        if (!journal->j_checkpoint_transactions)
                goto out;
@@ -334,7 +381,7 @@ restart:
                int batch_count = 0;
                struct buffer_head *bhs[NR_BATCH];
                struct journal_head *jh;
-               int retry = 0;
+               int retry = 0, err;
 
                while (!retry && transaction->t_checkpoint_list) {
                        struct buffer_head *bh;
@@ -347,6 +394,8 @@ restart:
                                break;
                        }
                        retry = __process_buffer(journal, jh, bhs,&batch_count);
+                       if (retry < 0 && !result)
+                               result = retry;
                        if (!retry && (need_resched() ||
                                spin_needbreak(&journal->j_list_lock))) {
                                spin_unlock(&journal->j_list_lock);
@@ -371,14 +420,18 @@ restart:
                 * Now we have cleaned up the first transaction's checkpoint
                 * list. Let's clean up the second one
                 */
-               __wait_cp_io(journal, transaction);
+               err = __wait_cp_io(journal, transaction);
+               if (!result)
+                       result = err;
        }
 out:
        spin_unlock(&journal->j_list_lock);
-       result = cleanup_journal_tail(journal);
        if (result < 0)
-               return result;
-       return 0;
+               journal_abort(journal, result);
+       else
+               result = cleanup_journal_tail(journal);
+
+       return (result < 0) ? result : 0;
 }
 
 /*
@@ -394,8 +447,9 @@ out:
  * This is the only part of the journaling code which really needs to be
  * aware of transaction aborts.  Checkpointing involves writing to the
  * main filesystem area rather than to the journal, so it can proceed
- * even in abort state, but we must not update the journal superblock if
- * we have an abort error outstanding.
+ * even in abort state, but we must not update the super block if
+ * checkpointing may have failed.  Otherwise, we would lose some metadata
+ * buffers which should be written-back to the filesystem.
  */
 
 int cleanup_journal_tail(journal_t *journal)
@@ -404,6 +458,9 @@ int cleanup_journal_tail(journal_t *journal)
        tid_t           first_tid;
        unsigned long   blocknr, freed;
 
+       if (is_journal_aborted(journal))
+               return 1;
+
        /* OK, work out the oldest transaction remaining in the log, and
         * the log block it starts at.
         *