ocfs2: improve fsync efficiency and fix deadlock between aio_write and sync_file

Currently, ocfs2_sync_file grabs i_mutex and forces the current journal
transaction to complete.  This isn't terribly efficient, since sync_file
really only needs to wait for the last transaction involving that inode
to complete, and this doesn't require i_mutex.

Therefore, implement the necessary bits to track the newest tid
associated with an inode, and teach sync_file to wait for that instead
of waiting for everything in the journal to commit.  Furthermore, only
issue the flush request to the drive if jbd2 hasn't already done so.

This also eliminates the deadlock between ocfs2_file_aio_write() and
ocfs2_sync_file().  aio_write takes i_mutex then calls
ocfs2_aiodio_wait() to wait for unaligned dio writes to finish.
However, if that dio completion involves calling fsync, then we can get
into trouble when some ocfs2_sync_file tries to take i_mutex.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

9 files changed, 74 insertions, 21 deletions

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index e2edff38be52..6b97d68e34d3 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6932,6 +6932,7 @@ int ocfs2_convert_inline_data_to_extents(struct inode *inode,
         di->i_dyn_features = cpu_to_le16(oi->ip_dyn_features);
         spin_unlock(&oi->ip_lock);
 
+        ocfs2_update_inode_fsync_trans(handle, inode, 1);
         ocfs2_dinode_new_extent_list(inode, di);
 
         ocfs2_journal_dirty(handle, di_bh);
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index ebe44f7dce0b..d310d12a9adc 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2039,6 +2039,7 @@ out_write_size:
         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
         di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
         di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
+        ocfs2_update_inode_fsync_trans(handle, inode, 1);
         ocfs2_journal_dirty(handle, wc->w_di_bh);
 
         ocfs2_commit_trans(osb, handle);
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 91a7e85ac8fd..8b48e9b7ad0e 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -2957,6 +2957,7 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
                 ocfs2_init_dir_trailer(dir, dirdata_bh, i);
         }
 
+        ocfs2_update_inode_fsync_trans(handle, dir, 1);
         ocfs2_journal_dirty(handle, dirdata_bh);
 
         if (ocfs2_supports_indexed_dirs(osb) && !dx_inline) {
@@ -3338,6 +3339,7 @@ do_extend:
         } else {
                 de->rec_len = cpu_to_le16(sb->s_blocksize);
         }
+        ocfs2_update_inode_fsync_trans(handle, dir, 1);
         ocfs2_journal_dirty(handle, new_bh);
 
         dir_i_size += dir->i_sb->s_blocksize;
@@ -3896,6 +3898,7 @@ out_commit:
                 dquot_free_space_nodirty(dir,
                                 ocfs2_clusters_to_bytes(dir->i_sb, 1));
 
+        ocfs2_update_inode_fsync_trans(handle, dir, 1);
         ocfs2_commit_trans(osb, handle);
 
 out:
@@ -4134,6 +4137,7 @@ static int ocfs2_expand_inline_dx_root(struct inode *dir,
                 mlog_errno(ret);
         did_quota = 0;
 
+        ocfs2_update_inode_fsync_trans(handle, dir, 1);
         ocfs2_journal_dirty(handle, dx_root_bh);
 
 out_commit:
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 1673438789fe..bd94d26b0b21 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -175,9 +175,13 @@ static int ocfs2_sync_file(struct file *file, loff_t start, loff_t end,
                            int datasync)
 {
         int err = 0;
-        journal_t *journal;
         struct inode *inode = file->f_mapping->host;
         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+        struct ocfs2_inode_info *oi = OCFS2_I(inode);
+        journal_t *journal = osb->journal->j_journal;
+        int ret;
+        tid_t commit_tid;
+        bool needs_barrier = false;
 
         trace_ocfs2_sync_file(inode, file, file->f_path.dentry,
                               OCFS2_I(inode)->ip_blkno,
@@ -192,29 +196,19 @@ static int ocfs2_sync_file(struct file *file, loff_t start, loff_t end,
         if (err)
                 return err;
 
-        /*
-         * Probably don't need the i_mutex at all in here, just putting it here
-         * to be consistent with how fsync used to be called, someone more
-         * familiar with the fs could possibly remove it.
-         */
-        mutex_lock(&inode->i_mutex);
-        if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) {
-                /*
-                 * We still have to flush drive's caches to get data to the
-                 * platter
-                 */
-                if (osb->s_mount_opt & OCFS2_MOUNT_BARRIER)
-                        blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
-                goto bail;
+        commit_tid = datasync ? oi->i_datasync_tid : oi->i_sync_tid;
+        if (journal->j_flags & JBD2_BARRIER &&
+            !jbd2_trans_will_send_data_barrier(journal, commit_tid))
+                needs_barrier = true;
+        err = jbd2_complete_transaction(journal, commit_tid);
+        if (needs_barrier) {
+                ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+                if (!err)
+                        err = ret;
         }
 
-        journal = osb->journal->j_journal;
-        err = jbd2_journal_force_commit(journal);
-
-bail:
         if (err)
                 mlog_errno(err);
-        mutex_unlock(&inode->i_mutex);
 
         return (err < 0) ? -EIO : 0;
 }
@@ -650,7 +644,7 @@ restarted_transaction:
                         mlog_errno(status);
                 goto leave;
         }
-
+        ocfs2_update_inode_fsync_trans(handle, inode, 1);
         ocfs2_journal_dirty(handle, bh);
 
         spin_lock(&OCFS2_I(inode)->ip_lock);
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index f29a90fde619..28ab8a9e88a1 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -130,6 +130,7 @@ struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
         struct inode *inode = NULL;
         struct super_block *sb = osb->sb;
         struct ocfs2_find_inode_args args;
+        journal_t *journal = OCFS2_SB(sb)->journal->j_journal;
 
         trace_ocfs2_iget_begin((unsigned long long)blkno, flags,
                                sysfile_type);
@@ -169,6 +170,32 @@ struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
                 goto bail;
         }
 
+        /*
+         * Set transaction id's of transactions that have to be committed
+         * to finish f[data]sync. We set them to currently running transaction
+         * as we cannot be sure that the inode or some of its metadata isn't
+         * part of the transaction - the inode could have been reclaimed and
+         * now it is reread from disk.
+         */
+        if (journal) {
+                transaction_t *transaction;
+                tid_t tid;
+                struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+                read_lock(&journal->j_state_lock);
+                if (journal->j_running_transaction)
+                        transaction = journal->j_running_transaction;
+                else
+                        transaction = journal->j_committing_transaction;
+                if (transaction)
+                        tid = transaction->t_tid;
+                else
+                        tid = journal->j_commit_sequence;
+                read_unlock(&journal->j_state_lock);
+                oi->i_sync_tid = tid;
+                oi->i_datasync_tid = tid;
+        }
+
 bail:
         if (!IS_ERR(inode)) {
                 trace_ocfs2_iget_end(inode, 
@@ -1260,6 +1287,7 @@ int ocfs2_mark_inode_dirty(handle_t *handle,
         fe->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
 
         ocfs2_journal_dirty(handle, bh);
+        ocfs2_update_inode_fsync_trans(handle, inode, 1);
 leave:
         return status;
 }
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 9f1580b506a5..837e5e42af85 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -73,6 +73,13 @@ struct ocfs2_inode_info
         u32                             ip_dir_lock_gen;
 
         struct ocfs2_alloc_reservation  ip_la_data_resv;
+
+        /*
+         * Transactions that contain inode's metadata needed to complete
+         * fsync and fdatasync, respectively.
+         */
+        tid_t i_sync_tid;
+        tid_t i_datasync_tid;
 };
 
 /*
diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index 9ff4e8cf9d97..7f8cde94abfe 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -626,4 +626,15 @@ static inline int ocfs2_begin_ordered_truncate(struct inode *inode,
                                 new_size);
 }
 
+static inline void ocfs2_update_inode_fsync_trans(handle_t *handle,
+                                                  struct inode *inode,
+                                                  int datasync)
+{
+        struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+        oi->i_sync_tid = handle->h_transaction->t_tid;
+        if (datasync)
+                oi->i_datasync_tid = handle->h_transaction->t_tid;
+}
+
 #endif /* OCFS2_JOURNAL_H */
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 3683643f3f0e..e61e4c9a077c 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -495,6 +495,7 @@ static int __ocfs2_mknod_locked(struct inode *dir,
         struct ocfs2_dinode *fe = NULL;
         struct ocfs2_extent_list *fel;
         u16 feat;
+        struct ocfs2_inode_info *oi = OCFS2_I(inode);
 
         *new_fe_bh = NULL;
 
@@ -576,6 +577,9 @@ static int __ocfs2_mknod_locked(struct inode *dir,
                         mlog_errno(status);
         }
 
+        oi->i_sync_tid = handle->h_transaction->t_tid;
+        oi->i_datasync_tid = handle->h_transaction->t_tid;
+
         status = 0; /* error in ocfs2_create_new_inode_locks is not
                      * critical */
 
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index d7190b2cfd40..9fef73da1ca5 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -561,6 +561,9 @@ static struct inode *ocfs2_alloc_inode(struct super_block *sb)
         if (!oi)
                 return NULL;
 
+        oi->i_sync_tid = 0;
+        oi->i_datasync_tid = 0;
+
         jbd2_journal_init_jbd_inode(&oi->ip_jinode, &oi->vfs_inode);
         return &oi->vfs_inode;
 }