1 files changed, 149 insertions, 49 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 8749a86f4175..da8d0eb3b7b9 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -21,6 +21,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/jiffies.h>
+#include <linux/crc32.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -93,19 +94,23 @@ static int inverted_lock(journal_t *journal, struct buffer_head *bh)
         return 1;
 }
 
-/* Done it all: now write the commit record.  We should have
+/*
+ * 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
  * entirely.
  *
  * Returns 1 if the journal needs to be aborted or 0 on success
  */
-static int journal_write_commit_record(journal_t *journal,
-                                        transaction_t *commit_transaction)
+static int journal_submit_commit_record(journal_t *journal,
+                                        transaction_t *commit_transaction,
+                                        struct buffer_head **cbh,
+                                        __u32 crc32_sum)
 {
         struct journal_head *descriptor;
+        struct commit_header *tmp;
         struct buffer_head *bh;
-        int i, ret;
+        int ret;
         int barrier_done = 0;
 
         if (is_journal_aborted(journal))
@@ -117,21 +122,33 @@ static int journal_write_commit_record(journal_t *journal,
 
         bh = jh2bh(descriptor);
 
-        /* AKPM: buglet - add `i' to tmp! */
-        for (i = 0; i < bh->b_size; i += 512) {
-                journal_header_t *tmp = (journal_header_t*)bh->b_data;
-                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 = (struct commit_header *)bh->b_data;
+        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);
+
+        if (JBD2_HAS_COMPAT_FEATURE(journal,
+                                    JBD2_FEATURE_COMPAT_CHECKSUM)) {
+                tmp->h_chksum_type      = JBD2_CRC32_CHKSUM;
+                tmp->h_chksum_size      = JBD2_CRC32_CHKSUM_SIZE;
+                tmp->h_chksum[0]        = cpu_to_be32(crc32_sum);
         }
 
-        JBUFFER_TRACE(descriptor, "write commit block");
+        JBUFFER_TRACE(descriptor, "submit commit block");
+        lock_buffer(bh);
+
         set_buffer_dirty(bh);
-        if (journal->j_flags & JBD2_BARRIER) {
+        set_buffer_uptodate(bh);
+        bh->b_end_io = journal_end_buffer_io_sync;
+
+        if (journal->j_flags & JBD2_BARRIER &&
+                !JBD2_HAS_COMPAT_FEATURE(journal,
+                                         JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
                 set_buffer_ordered(bh);
                 barrier_done = 1;
         }
-        ret = sync_dirty_buffer(bh);
+        ret = submit_bh(WRITE, bh);
+
         /* is it possible for another commit to fail at roughly
          * the same time as this one?  If so, we don't want to
          * trust the barrier flag in the super, but instead want
@@ -152,14 +169,72 @@ static int journal_write_commit_record(journal_t *journal,
                 clear_buffer_ordered(bh);
                 set_buffer_uptodate(bh);
                 set_buffer_dirty(bh);
-                ret = sync_dirty_buffer(bh);
+                ret = submit_bh(WRITE, bh);
         }
-        put_bh(bh);             /* One for getblk() */
-        jbd2_journal_put_journal_head(descriptor);
+        *cbh = bh;
+        return ret;
+}
+
+/*
+ * This function along with journal_submit_commit_record
+ * allows to write the commit record asynchronously.
+ */
+static int journal_wait_on_commit_record(struct buffer_head *bh)
+{
+        int ret = 0;
+
+        clear_buffer_dirty(bh);
+        wait_on_buffer(bh);
 
-        return (ret == -EIO);
+        if (unlikely(!buffer_uptodate(bh)))
+                ret = -EIO;
+        put_bh(bh);            /* One for getblk() */
+        jbd2_journal_put_journal_head(bh2jh(bh));
+
+        return ret;
 }
 
+/*
+ * Wait for all submitted IO to complete.
+ */
+static int journal_wait_on_locked_list(journal_t *journal,
+                                       transaction_t *commit_transaction)
+{
+        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);
+        }
+        return ret;
+  }
+
 static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
 {
         int i;
@@ -275,7 +350,21 @@ write_out_data:
         journal_do_submit_data(wbuf, bufs);
 }
 
-static inline void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
+static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
+{
+        struct page *page = bh->b_page;
+        char *addr;
+        __u32 checksum;
+
+        addr = kmap_atomic(page, KM_USER0);
+        checksum = crc32_be(crc32_sum,
+                (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
+        kunmap_atomic(addr, KM_USER0);
+
+        return checksum;
+}
+
+static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
                                    unsigned long long block)
 {
         tag->t_blocknr = cpu_to_be32(block & (u32)~0);
@@ -307,6 +396,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         int tag_flag;
         int i;
         int tag_bytes = journal_tag_bytes(journal);
+        struct buffer_head *cbh = NULL; /* For transactional checksums */
+        __u32 crc32_sum = ~0;
 
         /*
          * First job: lock down the current transaction and wait for
@@ -451,38 +542,15 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         journal_submit_data_buffers(journal, commit_transaction);
 
         /*
-         * Wait for all previously submitted IO to complete.
+         * Wait for all previously submitted IO to complete if commit
+         * record is to be written synchronously.
          */
         spin_lock(&journal->j_list_lock);
-        while (commit_transaction->t_locked_list) {
-                struct buffer_head *bh;
+        if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
+                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
+                err = journal_wait_on_locked_list(journal,
+                                                commit_transaction);
 
-                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)))
-                                err = -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);
-        }
         spin_unlock(&journal->j_list_lock);
 
         if (err)
@@ -656,6 +724,15 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 start_journal_io:
                         for (i = 0; i < bufs; i++) {
                                 struct buffer_head *bh = wbuf[i];
+                                /*
+                                 * Compute checksum.
+                                 */
+                                if (JBD2_HAS_COMPAT_FEATURE(journal,
+                                        JBD2_FEATURE_COMPAT_CHECKSUM)) {
+                                        crc32_sum =
+                                            jbd2_checksum_data(crc32_sum, bh);
+                                }
+
                                 lock_buffer(bh);
                                 clear_buffer_dirty(bh);
                                 set_buffer_uptodate(bh);
@@ -672,6 +749,23 @@ start_journal_io:
                 }
         }
 
+        /* Done it all: now write the commit record asynchronously. */
+
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
+                err = journal_submit_commit_record(journal, commit_transaction,
+                                                 &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);
+        }
+
         /* 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
@@ -771,8 +865,14 @@ wait_for_iobuf:
 
         jbd_debug(3, "JBD: commit phase 6\n");
 
-        if (journal_write_commit_record(journal, commit_transaction))
-                err = -EIO;
+        if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
+                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
+                err = journal_submit_commit_record(journal, commit_transaction,
+                                                &cbh, crc32_sum);
+                if (err)
+                        __jbd2_journal_abort_hard(journal);
+        }
+        err = journal_wait_on_commit_record(cbh);
 
         if (err)
                 jbd2_journal_abort(journal, err);