Merge branch 'linus' into timers/nohz

1 files changed, 106 insertions, 189 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 4d99685fdce4..f8b3be873226 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -22,6 +22,8 @@
 #include <linux/pagemap.h>
 #include <linux/jiffies.h>
 #include <linux/crc32.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -37,8 +39,8 @@ static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 }
 
 /*
- * When an ext3-ordered file is truncated, it is possible that many pages are
- * not sucessfully freed, because they are attached to a committing transaction.
+ * When an ext4 file is truncated, it is possible that some pages are not
+ * successfully freed, because they are attached to a committing transaction.
  * After the transaction commits, these pages are left on the LRU, with no
  * ->mapping, and with attached buffers.  These pages are trivially reclaimable
  * by the VM, but their apparent absence upsets the VM accounting, and it makes
@@ -80,21 +82,6 @@ nope:
 }
 
 /*
- * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
- * held.  For ranking reasons we must trylock.  If we lose, schedule away and
- * return 0.  j_list_lock is dropped in this case.
- */
-static int inverted_lock(journal_t *journal, struct buffer_head *bh)
-{
-        if (!jbd_trylock_bh_state(bh)) {
-                spin_unlock(&journal->j_list_lock);
-                schedule();
-                return 0;
-        }
-        return 1;
-}
-
-/*
  * Done it all: now submit the commit record.  We should have
  * cleaned up our previous buffers by now, so if we are in abort
  * mode we can now just skip the rest of the journal write
@@ -112,6 +99,7 @@ static int journal_submit_commit_record(journal_t *journal,
         struct buffer_head *bh;
         int ret;
         int barrier_done = 0;
+        struct timespec now = current_kernel_time();
 
         if (is_journal_aborted(journal))
                 return 0;
@@ -126,6 +114,8 @@ static int journal_submit_commit_record(journal_t *journal,
         tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
         tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
         tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
+        tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
+        tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
 
         if (JBD2_HAS_COMPAT_FEATURE(journal,
                                     JBD2_FEATURE_COMPAT_CHECKSUM)) {
@@ -168,6 +158,7 @@ static int journal_submit_commit_record(journal_t *journal,
                 spin_unlock(&journal->j_state_lock);
 
                 /* And try again, without the barrier */
+                lock_buffer(bh);
                 set_buffer_uptodate(bh);
                 set_buffer_dirty(bh);
                 ret = submit_bh(WRITE, bh);
@@ -196,159 +187,104 @@ static int journal_wait_on_commit_record(struct buffer_head *bh)
 }
 
 /*
- * Wait for all submitted IO to complete.
+ * write the filemap data using writepage() address_space_operations.
+ * We don't do block allocation here even for delalloc. We don't
+ * use writepages() because with dealyed allocation we may be doing
+ * block allocation in writepages().
  */
-static int journal_wait_on_locked_list(journal_t *journal,
-                                       transaction_t *commit_transaction)
+static int journal_submit_inode_data_buffers(struct address_space *mapping)
 {
-        int ret = 0;
-        struct journal_head *jh;
-
-        while (commit_transaction->t_locked_list) {
-                struct buffer_head *bh;
-
-                jh = commit_transaction->t_locked_list->b_tprev;
-                bh = jh2bh(jh);
-                get_bh(bh);
-                if (buffer_locked(bh)) {
-                        spin_unlock(&journal->j_list_lock);
-                        wait_on_buffer(bh);
-                        if (unlikely(!buffer_uptodate(bh)))
-                                ret = -EIO;
-                        spin_lock(&journal->j_list_lock);
-                }
-                if (!inverted_lock(journal, bh)) {
-                        put_bh(bh);
-                        spin_lock(&journal->j_list_lock);
-                        continue;
-                }
-                if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
-                        __jbd2_journal_unfile_buffer(jh);
-                        jbd_unlock_bh_state(bh);
-                        jbd2_journal_remove_journal_head(bh);
-                        put_bh(bh);
-                } else {
-                        jbd_unlock_bh_state(bh);
-                }
-                put_bh(bh);
-                cond_resched_lock(&journal->j_list_lock);
-        }
+        int ret;
+        struct writeback_control wbc = {
+                .sync_mode =  WB_SYNC_ALL,
+                .nr_to_write = mapping->nrpages * 2,
+                .range_start = 0,
+                .range_end = i_size_read(mapping->host),
+                .for_writepages = 1,
+        };
+
+        ret = generic_writepages(mapping, &wbc);
         return ret;
-  }
+}
 
-static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
+/*
+ * Submit all the data buffers of inode associated with the transaction to
+ * disk.
+ *
+ * We are in a committing transaction. Therefore no new inode can be added to
+ * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
+ * operate on from being released while we write out pages.
+ */
+static int journal_submit_data_buffers(journal_t *journal,
+                transaction_t *commit_transaction)
 {
-        int i;
+        struct jbd2_inode *jinode;
+        int err, ret = 0;
+        struct address_space *mapping;
 
-        for (i = 0; i < bufs; i++) {
-                wbuf[i]->b_end_io = end_buffer_write_sync;
-                /* We use-up our safety reference in submit_bh() */
-                submit_bh(WRITE, wbuf[i]);
+        spin_lock(&journal->j_list_lock);
+        list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+                mapping = jinode->i_vfs_inode->i_mapping;
+                jinode->i_flags |= JI_COMMIT_RUNNING;
+                spin_unlock(&journal->j_list_lock);
+                /*
+                 * submit the inode data buffers. We use writepage
+                 * instead of writepages. Because writepages can do
+                 * block allocation  with delalloc. We need to write
+                 * only allocated blocks here.
+                 */
+                err = journal_submit_inode_data_buffers(mapping);
+                if (!ret)
+                        ret = err;
+                spin_lock(&journal->j_list_lock);
+                J_ASSERT(jinode->i_transaction == commit_transaction);
+                jinode->i_flags &= ~JI_COMMIT_RUNNING;
+                wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
         }
+        spin_unlock(&journal->j_list_lock);
+        return ret;
 }
 
 /*
- *  Submit all the data buffers to disk
+ * Wait for data submitted for writeout, refile inodes to proper
+ * transaction if needed.
+ *
  */
-static void journal_submit_data_buffers(journal_t *journal,
-                                transaction_t *commit_transaction)
+static int journal_finish_inode_data_buffers(journal_t *journal,
+                transaction_t *commit_transaction)
 {
-        struct journal_head *jh;
-        struct buffer_head *bh;
-        int locked;
-        int bufs = 0;
-        struct buffer_head **wbuf = journal->j_wbuf;
+        struct jbd2_inode *jinode, *next_i;
+        int err, ret = 0;
 
-        /*
-         * Whenever we unlock the journal and sleep, things can get added
-         * onto ->t_sync_datalist, so we have to keep looping back to
-         * write_out_data until we *know* that the list is empty.
-         *
-         * Cleanup any flushed data buffers from the data list.  Even in
-         * abort mode, we want to flush this out as soon as possible.
-         */
-write_out_data:
-        cond_resched();
+        /* For locking, see the comment in journal_submit_data_buffers() */
         spin_lock(&journal->j_list_lock);
+        list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+                jinode->i_flags |= JI_COMMIT_RUNNING;
+                spin_unlock(&journal->j_list_lock);
+                err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
+                if (!ret)
+                        ret = err;
+                spin_lock(&journal->j_list_lock);
+                jinode->i_flags &= ~JI_COMMIT_RUNNING;
+                wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+        }
 
-        while (commit_transaction->t_sync_datalist) {
-                jh = commit_transaction->t_sync_datalist;
-                bh = jh2bh(jh);
-                locked = 0;
-
-                /* Get reference just to make sure buffer does not disappear
-                 * when we are forced to drop various locks */
-                get_bh(bh);
-                /* If the buffer is dirty, we need to submit IO and hence
-                 * we need the buffer lock. We try to lock the buffer without
-                 * blocking. If we fail, we need to drop j_list_lock and do
-                 * blocking lock_buffer().
-                 */
-                if (buffer_dirty(bh)) {
-                        if (test_set_buffer_locked(bh)) {
-                                BUFFER_TRACE(bh, "needs blocking lock");
-                                spin_unlock(&journal->j_list_lock);
-                                /* Write out all data to prevent deadlocks */
-                                journal_do_submit_data(wbuf, bufs);
-                                bufs = 0;
-                                lock_buffer(bh);
-                                spin_lock(&journal->j_list_lock);
-                        }
-                        locked = 1;
-                }
-                /* We have to get bh_state lock. Again out of order, sigh. */
-                if (!inverted_lock(journal, bh)) {
-                        jbd_lock_bh_state(bh);
-                        spin_lock(&journal->j_list_lock);
-                }
-                /* Someone already cleaned up the buffer? */
-                if (!buffer_jbd(bh)
-                        || jh->b_transaction != commit_transaction
-                        || jh->b_jlist != BJ_SyncData) {
-                        jbd_unlock_bh_state(bh);
-                        if (locked)
-                                unlock_buffer(bh);
-                        BUFFER_TRACE(bh, "already cleaned up");
-                        put_bh(bh);
-                        continue;
-                }
-                if (locked && test_clear_buffer_dirty(bh)) {
-                        BUFFER_TRACE(bh, "needs writeout, adding to array");
-                        wbuf[bufs++] = bh;
-                        __jbd2_journal_file_buffer(jh, commit_transaction,
-                                                BJ_Locked);
-                        jbd_unlock_bh_state(bh);
-                        if (bufs == journal->j_wbufsize) {
-                                spin_unlock(&journal->j_list_lock);
-                                journal_do_submit_data(wbuf, bufs);
-                                bufs = 0;
-                                goto write_out_data;
-                        }
-                } else if (!locked && buffer_locked(bh)) {
-                        __jbd2_journal_file_buffer(jh, commit_transaction,
-                                                BJ_Locked);
-                        jbd_unlock_bh_state(bh);
-                        put_bh(bh);
+        /* Now refile inode to proper lists */
+        list_for_each_entry_safe(jinode, next_i,
+                                 &commit_transaction->t_inode_list, i_list) {
+                list_del(&jinode->i_list);
+                if (jinode->i_next_transaction) {
+                        jinode->i_transaction = jinode->i_next_transaction;
+                        jinode->i_next_transaction = NULL;
+                        list_add(&jinode->i_list,
+                                &jinode->i_transaction->t_inode_list);
                 } else {
-                        BUFFER_TRACE(bh, "writeout complete: unfile");
-                        __jbd2_journal_unfile_buffer(jh);
-                        jbd_unlock_bh_state(bh);
-                        if (locked)
-                                unlock_buffer(bh);
-                        jbd2_journal_remove_journal_head(bh);
-                        /* Once for our safety reference, once for
-                         * jbd2_journal_remove_journal_head() */
-                        put_bh(bh);
-                        put_bh(bh);
-                }
-
-                if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
-                        spin_unlock(&journal->j_list_lock);
-                        goto write_out_data;
+                        jinode->i_transaction = NULL;
                 }
         }
         spin_unlock(&journal->j_list_lock);
-        journal_do_submit_data(wbuf, bufs);
+
+        return ret;
 }
 
 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
@@ -523,21 +459,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
          * Now start flushing things to disk, in the order they appear
          * on the transaction lists.  Data blocks go first.
          */
-        err = 0;
-        journal_submit_data_buffers(journal, commit_transaction);
-
-        /*
-         * Wait for all previously submitted IO to complete if commit
-         * record is to be written synchronously.
-         */
-        spin_lock(&journal->j_list_lock);
-        if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
-                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
-                err = journal_wait_on_locked_list(journal,
-                                                commit_transaction);
-
-        spin_unlock(&journal->j_list_lock);
-
+        err = journal_submit_data_buffers(journal, commit_transaction);
         if (err)
                 jbd2_journal_abort(journal, err);
 
@@ -546,16 +468,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         jbd_debug(3, "JBD: commit phase 2\n");
 
         /*
-         * If we found any dirty or locked buffers, then we should have
-         * looped back up to the write_out_data label.  If there weren't
-         * any then journal_clean_data_list should have wiped the list
-         * clean by now, so check that it is in fact empty.
-         */
-        J_ASSERT (commit_transaction->t_sync_datalist == NULL);
-
-        jbd_debug (3, "JBD: commit phase 3\n");
-
-        /*
          * Way to go: we have now written out all of the data for a
          * transaction!  Now comes the tricky part: we need to write out
          * metadata.  Loop over the transaction's entire buffer list:
@@ -573,6 +485,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         J_ASSERT(commit_transaction->t_nr_buffers <=
                  commit_transaction->t_outstanding_credits);
 
+        err = 0;
         descriptor = NULL;
         bufs = 0;
         while (commit_transaction->t_buffers) {
@@ -747,15 +660,19 @@ start_journal_io:
                                                  &cbh, crc32_sum);
                 if (err)
                         __jbd2_journal_abort_hard(journal);
-
-                spin_lock(&journal->j_list_lock);
-                err = journal_wait_on_locked_list(journal,
-                                                commit_transaction);
-                spin_unlock(&journal->j_list_lock);
-                if (err)
-                        __jbd2_journal_abort_hard(journal);
         }
 
+        /*
+         * This is the right place to wait for data buffers both for ASYNC
+         * and !ASYNC commit. If commit is ASYNC, we need to wait only after
+         * the commit block went to disk (which happens above). If commit is
+         * SYNC, we need to wait for data buffers before we start writing
+         * commit block, which happens below in such setting.
+         */
+        err = journal_finish_inode_data_buffers(journal, commit_transaction);
+        if (err)
+                jbd2_journal_abort(journal, err);
+
         /* Lo and behold: we have just managed to send a transaction to
            the log.  Before we can commit it, wait for the IO so far to
            complete.  Control buffers being written are on the
@@ -767,7 +684,7 @@ start_journal_io:
            so we incur less scheduling load.
         */
 
-        jbd_debug(3, "JBD: commit phase 4\n");
+        jbd_debug(3, "JBD: commit phase 3\n");
 
         /*
          * akpm: these are BJ_IO, and j_list_lock is not needed.
@@ -826,7 +743,7 @@ wait_for_iobuf:
 
         J_ASSERT (commit_transaction->t_shadow_list == NULL);
 
-        jbd_debug(3, "JBD: commit phase 5\n");
+        jbd_debug(3, "JBD: commit phase 4\n");
 
         /* Here we wait for the revoke record and descriptor record buffers */
  wait_for_ctlbuf:
@@ -853,7 +770,7 @@ wait_for_iobuf:
                 /* AKPM: bforget here */
         }
 
-        jbd_debug(3, "JBD: commit phase 6\n");
+        jbd_debug(3, "JBD: commit phase 5\n");
 
         if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
                 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
@@ -873,9 +790,9 @@ wait_for_iobuf:
            transaction can be removed from any checkpoint list it was on
            before. */
 
-        jbd_debug(3, "JBD: commit phase 7\n");
+        jbd_debug(3, "JBD: commit phase 6\n");
 
-        J_ASSERT(commit_transaction->t_sync_datalist == NULL);
+        J_ASSERT(list_empty(&commit_transaction->t_inode_list));
         J_ASSERT(commit_transaction->t_buffers == NULL);
         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
         J_ASSERT(commit_transaction->t_iobuf_list == NULL);
@@ -996,7 +913,7 @@ restart_loop:
 
         /* Done with this transaction! */
 
-        jbd_debug(3, "JBD: commit phase 8\n");
+        jbd_debug(3, "JBD: commit phase 7\n");
 
         J_ASSERT(commit_transaction->t_state == T_COMMIT);