1 files changed, 75 insertions, 94 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 7c068c189d80..eef6979821a4 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -26,7 +26,9 @@
 #include <linux/backing-dev.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/bitops.h>
 #include <trace/events/jbd2.h>
+#include <asm/system.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -103,6 +105,8 @@ static int journal_submit_commit_record(journal_t *journal,
         int ret;
         struct timespec now = current_kernel_time();
 
+        *cbh = NULL;
+
         if (is_journal_aborted(journal))
                 return 0;
 
@@ -134,25 +138,11 @@ static int journal_submit_commit_record(journal_t *journal,
 
         if (journal->j_flags & JBD2_BARRIER &&
             !JBD2_HAS_INCOMPAT_FEATURE(journal,
-                                       JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
-                ret = submit_bh(WRITE_SYNC_PLUG | WRITE_BARRIER, bh);
-                if (ret == -EOPNOTSUPP) {
-                        printk(KERN_WARNING
-                               "JBD2: Disabling barriers on %s, "
-                               "not supported by device\n", journal->j_devname);
-                        write_lock(&journal->j_state_lock);
-                        journal->j_flags &= ~JBD2_BARRIER;
-                        write_unlock(&journal->j_state_lock);
+                                       JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
+                ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
+        else
+                ret = submit_bh(WRITE_SYNC, bh);
 
-                        /* And try again, without the barrier */
-                        lock_buffer(bh);
-                        set_buffer_uptodate(bh);
-                        clear_buffer_dirty(bh);
-                        ret = submit_bh(WRITE_SYNC_PLUG, bh);
-                }
-        } else {
-                ret = submit_bh(WRITE_SYNC_PLUG, bh);
-        }
         *cbh = bh;
         return ret;
 }
@@ -166,29 +156,8 @@ static int journal_wait_on_commit_record(journal_t *journal,
 {
         int ret = 0;
 
-retry:
         clear_buffer_dirty(bh);
         wait_on_buffer(bh);
-        if (buffer_eopnotsupp(bh) && (journal->j_flags & JBD2_BARRIER)) {
-                printk(KERN_WARNING
-                       "JBD2: %s: disabling barries on %s - not supported "
-                       "by device\n", __func__, journal->j_devname);
-                write_lock(&journal->j_state_lock);
-                journal->j_flags &= ~JBD2_BARRIER;
-                write_unlock(&journal->j_state_lock);
-
-                lock_buffer(bh);
-                clear_buffer_dirty(bh);
-                set_buffer_uptodate(bh);
-                bh->b_end_io = journal_end_buffer_io_sync;
-
-                ret = submit_bh(WRITE_SYNC_PLUG, bh);
-                if (ret) {
-                        unlock_buffer(bh);
-                        return ret;
-                }
-                goto retry;
-        }
 
         if (unlikely(!buffer_uptodate(bh)))
                 ret = -EIO;
@@ -236,7 +205,7 @@ static int journal_submit_data_buffers(journal_t *journal,
         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;
+                set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
                 spin_unlock(&journal->j_list_lock);
                 /*
                  * submit the inode data buffers. We use writepage
@@ -250,8 +219,8 @@ static int journal_submit_data_buffers(journal_t *journal,
                         ret = err;
                 spin_lock(&journal->j_list_lock);
                 J_ASSERT(jinode->i_transaction == commit_transaction);
-                commit_transaction->t_flushed_data_blocks = 1;
-                jinode->i_flags &= ~JI_COMMIT_RUNNING;
+                clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+                smp_mb__after_clear_bit();
                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
         }
         spin_unlock(&journal->j_list_lock);
@@ -272,7 +241,7 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
         /* 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;
+                set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
                 spin_unlock(&journal->j_list_lock);
                 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
                 if (err) {
@@ -288,7 +257,8 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
                                 ret = err;
                 }
                 spin_lock(&journal->j_list_lock);
-                jinode->i_flags &= ~JI_COMMIT_RUNNING;
+                clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+                smp_mb__after_clear_bit();
                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
         }
 
@@ -360,19 +330,13 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         int tag_bytes = journal_tag_bytes(journal);
         struct buffer_head *cbh = NULL; /* For transactional checksums */
         __u32 crc32_sum = ~0;
-        int write_op = WRITE;
+        struct blk_plug plug;
 
         /*
          * First job: lock down the current transaction and wait for
          * all outstanding updates to complete.
          */
 
-#ifdef COMMIT_STATS
-        spin_lock(&journal->j_list_lock);
-        summarise_journal_usage(journal);
-        spin_unlock(&journal->j_list_lock);
-#endif
-
         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
         if (journal->j_flags & JBD2_FLUSHED) {
                 jbd_debug(3, "super block updated\n");
@@ -394,13 +358,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         write_lock(&journal->j_state_lock);
         commit_transaction->t_state = T_LOCKED;
 
-        /*
-         * Use plugged writes here, since we want to submit several before
-         * we unplug the device. We don't do explicit unplugging in here,
-         * instead we rely on sync_buffer() doing the unplug for us.
-         */
-        if (commit_transaction->t_synchronous_commit)
-                write_op = WRITE_SYNC_PLUG;
         trace_jbd2_commit_locking(journal, commit_transaction);
         stats.run.rs_wait = commit_transaction->t_max_wait;
         stats.run.rs_locked = jiffies;
@@ -441,7 +398,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
          * we do not require it to remember exactly which old buffers it
          * has reserved.  This is consistent with the existing behaviour
          * that multiple jbd2_journal_get_write_access() calls to the same
-         * buffer are perfectly permissable.
+         * buffer are perfectly permissible.
          */
         while (commit_transaction->t_reserved_list) {
                 jh = commit_transaction->t_reserved_list;
@@ -500,8 +457,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         if (err)
                 jbd2_journal_abort(journal, err);
 
+        blk_start_plug(&plug);
         jbd2_journal_write_revoke_records(journal, commit_transaction,
-                                          write_op);
+                                          WRITE_SYNC);
+        blk_finish_plug(&plug);
 
         jbd_debug(3, "JBD: commit phase 2\n");
 
@@ -528,6 +487,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         err = 0;
         descriptor = NULL;
         bufs = 0;
+        blk_start_plug(&plug);
         while (commit_transaction->t_buffers) {
 
                 /* Find the next buffer to be journaled... */
@@ -689,7 +649,7 @@ start_journal_io:
                                 clear_buffer_dirty(bh);
                                 set_buffer_uptodate(bh);
                                 bh->b_end_io = journal_end_buffer_io_sync;
-                                submit_bh(write_op, bh);
+                                submit_bh(WRITE_SYNC, bh);
                         }
                         cond_resched();
                         stats.run.rs_blocks_logged += bufs;
@@ -701,16 +661,29 @@ start_journal_io:
                 }
         }
 
+        err = journal_finish_inode_data_buffers(journal, commit_transaction);
+        if (err) {
+                printk(KERN_WARNING
+                        "JBD2: Detected IO errors while flushing file data "
+                       "on %s\n", journal->j_devname);
+                if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
+                        jbd2_journal_abort(journal, err);
+                err = 0;
+        }
+
+        write_lock(&journal->j_state_lock);
+        J_ASSERT(commit_transaction->t_state == T_COMMIT);
+        commit_transaction->t_state = T_COMMIT_DFLUSH;
+        write_unlock(&journal->j_state_lock);
         /* 
          * If the journal is not located on the file system device,
          * then we must flush the file system device before we issue
          * the commit record
          */
-        if (commit_transaction->t_flushed_data_blocks &&
+        if (commit_transaction->t_need_data_flush &&
             (journal->j_fs_dev != journal->j_dev) &&
             (journal->j_flags & JBD2_BARRIER))
-                blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL,
-                        BLKDEV_IFL_WAIT);
+                blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 
         /* Done it all: now write the commit record asynchronously. */
         if (JBD2_HAS_INCOMPAT_FEATURE(journal,
@@ -719,20 +692,9 @@ start_journal_io:
                                                  &cbh, crc32_sum);
                 if (err)
                         __jbd2_journal_abort_hard(journal);
-                if (journal->j_flags & JBD2_BARRIER)
-                        blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL,
-                                BLKDEV_IFL_WAIT);
         }
 
-        err = journal_finish_inode_data_buffers(journal, commit_transaction);
-        if (err) {
-                printk(KERN_WARNING
-                        "JBD2: Detected IO errors while flushing file data "
-                       "on %s\n", journal->j_devname);
-                if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
-                        jbd2_journal_abort(journal, err);
-                err = 0;
-        }
+        blk_finish_plug(&plug);
 
         /* 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
@@ -795,8 +757,13 @@ wait_for_iobuf:
                    required. */
                 JBUFFER_TRACE(jh, "file as BJ_Forget");
                 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
-                /* Wake up any transactions which were waiting for this
-                   IO to complete */
+                /*
+                 * Wake up any transactions which were waiting for this IO to
+                 * complete. The barrier must be here so that changes by
+                 * jbd2_journal_file_buffer() take effect before wake_up_bit()
+                 * does the waitqueue check.
+                 */
+                smp_mb();
                 wake_up_bit(&bh->b_state, BH_Unshadow);
                 JBUFFER_TRACE(jh, "brelse shadowed buffer");
                 __brelse(bh);
@@ -835,6 +802,10 @@ wait_for_iobuf:
                 jbd2_journal_abort(journal, err);
 
         jbd_debug(3, "JBD: commit phase 5\n");
+        write_lock(&journal->j_state_lock);
+        J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
+        commit_transaction->t_state = T_COMMIT_JFLUSH;
+        write_unlock(&journal->j_state_lock);
 
         if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
                                        JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
@@ -843,8 +814,13 @@ wait_for_iobuf:
                 if (err)
                         __jbd2_journal_abort_hard(journal);
         }
-        if (!err && !is_journal_aborted(journal))
+        if (cbh)
                 err = journal_wait_on_commit_record(journal, cbh);
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+                                      JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
+            journal->j_flags & JBD2_BARRIER) {
+                blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL);
+        }
 
         if (err)
                 jbd2_journal_abort(journal, err);
@@ -872,10 +848,16 @@ restart_loop:
         while (commit_transaction->t_forget) {
                 transaction_t *cp_transaction;
                 struct buffer_head *bh;
+                int try_to_free = 0;
 
                 jh = commit_transaction->t_forget;
                 spin_unlock(&journal->j_list_lock);
                 bh = jh2bh(jh);
+                /*
+                 * Get a reference so that bh cannot be freed before we are
+                 * done with it.
+                 */
+                get_bh(bh);
                 jbd_lock_bh_state(bh);
                 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
 
@@ -938,28 +920,27 @@ restart_loop:
                         __jbd2_journal_insert_checkpoint(jh, commit_transaction);
                         if (is_journal_aborted(journal))
                                 clear_buffer_jbddirty(bh);
-                        JBUFFER_TRACE(jh, "refile for checkpoint writeback");
-                        __jbd2_journal_refile_buffer(jh);
-                        jbd_unlock_bh_state(bh);
                 } else {
                         J_ASSERT_BH(bh, !buffer_dirty(bh));
-                        /* The buffer on BJ_Forget list and not jbddirty means
+                        /*
+                         * The buffer on BJ_Forget list and not jbddirty means
                          * it has been freed by this transaction and hence it
                          * could not have been reallocated until this
                          * transaction has committed. *BUT* it could be
                          * reallocated once we have written all the data to
                          * disk and before we process the buffer on BJ_Forget
-                         * list. */
-                        JBUFFER_TRACE(jh, "refile or unfile freed buffer");
-                        __jbd2_journal_refile_buffer(jh);
-                        if (!jh->b_transaction) {
-                                jbd_unlock_bh_state(bh);
-                                 /* needs a brelse */
-                                jbd2_journal_remove_journal_head(bh);
-                                release_buffer_page(bh);
-                        } else
-                                jbd_unlock_bh_state(bh);
+                         * list.
+                         */
+                        if (!jh->b_next_transaction)
+                                try_to_free = 1;
                 }
+                JBUFFER_TRACE(jh, "refile or unfile buffer");
+                __jbd2_journal_refile_buffer(jh);
+                jbd_unlock_bh_state(bh);
+                if (try_to_free)
+                        release_buffer_page(bh);        /* Drops bh reference */
+                else
+                        __brelse(bh);
                 cond_resched_lock(&journal->j_list_lock);
         }
         spin_unlock(&journal->j_list_lock);
@@ -985,7 +966,7 @@ restart_loop:
 
         jbd_debug(3, "JBD: commit phase 7\n");
 
-        J_ASSERT(commit_transaction->t_state == T_COMMIT);
+        J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
 
         commit_transaction->t_start = jiffies;
         stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,