zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/fs/ext4/fsync.c b/ap/os/linux/linux-3.4.x/fs/ext4/fsync.c
new file mode 100644
index 0000000..019c29c
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/ext4/fsync.c
@@ -0,0 +1,270 @@
+/*
+ * linux/fs/ext4/fsync.c
+ *
+ * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com)
+ * from
+ * Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ * from
+ * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * ext4fs fsync primitive
+ *
+ * Big-endian to little-endian byte-swapping/bitmaps by
+ * David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Removed unnecessary code duplication for little endian machines
+ * and excessive __inline__s.
+ * Andi Kleen, 1997
+ *
+ * Major simplications and cleanup - we only need to do the metadata, because
+ * we can depend on generic_block_fdatasync() to sync the data blocks.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/jbd2.h>
+#include <linux/blkdev.h>
+
+#include "ext4.h"
+#include "ext4_jbd2.h"
+
+#include <trace/events/ext4.h>
+
+static void dump_completed_IO(struct inode * inode)
+{
+#ifdef EXT4FS_DEBUG
+ struct list_head *cur, *before, *after;
+ ext4_io_end_t *io, *io0, *io1;
+ unsigned long flags;
+
+ if (list_empty(&EXT4_I(inode)->i_completed_io_list)){
+ ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino);
+ return;
+ }
+
+ ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino);
+ spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
+ list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){
+ cur = &io->list;
+ before = cur->prev;
+ io0 = container_of(before, ext4_io_end_t, list);
+ after = cur->next;
+ io1 = container_of(after, ext4_io_end_t, list);
+
+ ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
+ io, inode->i_ino, io0, io1);
+ }
+ spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
+#endif
+}
+
+/*
+ * This function is called from ext4_sync_file().
+ *
+ * When IO is completed, the work to convert unwritten extents to
+ * written is queued on workqueue but may not get immediately
+ * scheduled. When fsync is called, we need to ensure the
+ * conversion is complete before fsync returns.
+ * The inode keeps track of a list of pending/completed IO that
+ * might needs to do the conversion. This function walks through
+ * the list and convert the related unwritten extents for completed IO
+ * to written.
+ * The function return the number of pending IOs on success.
+ */
+int ext4_flush_completed_IO(struct inode *inode)
+{
+ ext4_io_end_t *io;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ unsigned long flags;
+ int ret = 0;
+ int ret2 = 0;
+
+ dump_completed_IO(inode);
+ spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+ while (!list_empty(&ei->i_completed_io_list)){
+ io = list_entry(ei->i_completed_io_list.next,
+ ext4_io_end_t, list);
+ list_del_init(&io->list);
+ io->flag |= EXT4_IO_END_IN_FSYNC;
+ /*
+ * Calling ext4_end_io_nolock() to convert completed
+ * IO to written.
+ *
+ * When ext4_sync_file() is called, run_queue() may already
+ * about to flush the work corresponding to this io structure.
+ * It will be upset if it founds the io structure related
+ * to the work-to-be schedule is freed.
+ *
+ * Thus we need to keep the io structure still valid here after
+ * conversion finished. The io structure has a flag to
+ * avoid double converting from both fsync and background work
+ * queue work.
+ */
+ spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+ ret = ext4_end_io_nolock(io);
+ if (ret < 0)
+ ret2 = ret;
+ spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+ io->flag &= ~EXT4_IO_END_IN_FSYNC;
+ }
+ spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+ return (ret2 < 0) ? ret2 : 0;
+}
+
+/*
+ * If we're not journaling and this is a just-created file, we have to
+ * sync our parent directory (if it was freshly created) since
+ * otherwise it will only be written by writeback, leaving a huge
+ * window during which a crash may lose the file. This may apply for
+ * the parent directory's parent as well, and so on recursively, if
+ * they are also freshly created.
+ */
+static int ext4_sync_parent(struct inode *inode)
+{
+ struct writeback_control wbc;
+ struct dentry *dentry = NULL;
+ struct inode *next;
+ int ret = 0;
+
+ if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY))
+ return 0;
+ inode = igrab(inode);
+ while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) {
+ ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY);
+ dentry = NULL;
+ spin_lock(&inode->i_lock);
+ if (!list_empty(&inode->i_dentry)) {
+ dentry = list_first_entry(&inode->i_dentry,
+ struct dentry, d_u.d_alias);
+ dget(dentry);
+ }
+ spin_unlock(&inode->i_lock);
+ if (!dentry)
+ break;
+ next = igrab(dentry->d_parent->d_inode);
+ dput(dentry);
+ if (!next)
+ break;
+ iput(inode);
+ inode = next;
+ ret = sync_mapping_buffers(inode->i_mapping);
+ if (ret)
+ break;
+ memset(&wbc, 0, sizeof(wbc));
+ wbc.sync_mode = WB_SYNC_ALL;
+ wbc.nr_to_write = 0; /* only write out the inode */
+ ret = sync_inode(inode, &wbc);
+ if (ret)
+ break;
+ }
+ iput(inode);
+ return ret;
+}
+
+/**
+ * __sync_file - generic_file_fsync without the locking and filemap_write
+ * @inode: inode to sync
+ * @datasync: only sync essential metadata if true
+ *
+ * This is just generic_file_fsync without the locking. This is needed for
+ * nojournal mode to make sure this inodes data/metadata makes it to disk
+ * properly. The i_mutex should be held already.
+ */
+static int __sync_inode(struct inode *inode, int datasync)
+{
+ int err;
+ int ret;
+
+ ret = sync_mapping_buffers(inode->i_mapping);
+ if (!(inode->i_state & I_DIRTY))
+ return ret;
+ if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+ return ret;
+
+ err = sync_inode_metadata(inode, 1);
+ if (ret == 0)
+ ret = err;
+ return ret;
+}
+
+/*
+ * akpm: A new design for ext4_sync_file().
+ *
+ * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
+ * There cannot be a transaction open by this task.
+ * Another task could have dirtied this inode. Its data can be in any
+ * state in the journalling system.
+ *
+ * What we do is just kick off a commit and wait on it. This will snapshot the
+ * inode to disk.
+ *
+ * i_mutex lock is held when entering and exiting this function
+ */
+
+int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+ int ret;
+ tid_t commit_tid;
+ bool needs_barrier = false;
+
+ J_ASSERT(ext4_journal_current_handle() == NULL);
+
+ trace_ext4_sync_file_enter(file, datasync);
+
+ ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (ret)
+ return ret;
+ mutex_lock(&inode->i_mutex);
+
+ if (inode->i_sb->s_flags & MS_RDONLY)
+ goto out;
+
+ ret = ext4_flush_completed_IO(inode);
+ if (ret < 0)
+ goto out;
+
+ if (!journal) {
+ ret = __sync_inode(inode, datasync);
+ if (!ret && !list_empty(&inode->i_dentry))
+ ret = ext4_sync_parent(inode);
+ goto out;
+ }
+
+ /*
+ * data=writeback,ordered:
+ * The caller's filemap_fdatawrite()/wait will sync the data.
+ * Metadata is in the journal, we wait for proper transaction to
+ * commit here.
+ *
+ * data=journal:
+ * filemap_fdatawrite won't do anything (the buffers are clean).
+ * ext4_force_commit will write the file data into the journal and
+ * will wait on that.
+ * filemap_fdatawait() will encounter a ton of newly-dirtied pages
+ * (they were dirtied by commit). But that's OK - the blocks are
+ * safe in-journal, which is all fsync() needs to ensure.
+ */
+ if (ext4_should_journal_data(inode)) {
+ ret = ext4_force_commit(inode->i_sb);
+ goto out;
+ }
+
+ commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid;
+ if (journal->j_flags & JBD2_BARRIER &&
+ !jbd2_trans_will_send_data_barrier(journal, commit_tid))
+ needs_barrier = true;
+ ret = jbd2_complete_transaction(journal, commit_tid);
+ if (needs_barrier)
+ blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+ out:
+ mutex_unlock(&inode->i_mutex);
+ trace_ext4_sync_file_exit(inode, ret);
+ return ret;
+}