1 files changed, 55 insertions, 26 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 571ad3c13b47..06550affbd27 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -123,7 +123,10 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 
         end_of_last_block = start_pos + num_bytes - 1;
-        btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+        err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+        if (err)
+                return err;
+
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
                 SetPageUptodate(p);
@@ -875,7 +878,8 @@ again:
                         btrfs_put_ordered_extent(ordered);
 
                 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
-                                  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
+                                  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
+                                  EXTENT_DO_ACCOUNTING,
                                   GFP_NOFS);
                 unlock_extent(&BTRFS_I(inode)->io_tree,
                               start_pos, last_pos - 1, GFP_NOFS);
@@ -917,21 +921,35 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
         start_pos = pos;
 
         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+        /* do the reserve before the mutex lock in case we have to do some
+         * flushing.  We wouldn't deadlock, but this is more polite.
+         */
+        err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+        if (err)
+                goto out_nolock;
+
+        mutex_lock(&inode->i_mutex);
+
         current->backing_dev_info = inode->i_mapping->backing_dev_info;
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
         if (err)
-                goto out_nolock;
+                goto out;
+
         if (count == 0)
-                goto out_nolock;
+                goto out;
 
         err = file_remove_suid(file);
         if (err)
-                goto out_nolock;
+                goto out;
+
         file_update_time(file);
 
         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 
-        mutex_lock(&inode->i_mutex);
+        /* generic_write_checks can change our pos */
+        start_pos = pos;
+
         BTRFS_I(inode)->sequence++;
         first_index = pos >> PAGE_CACHE_SHIFT;
         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
@@ -1005,9 +1023,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 }
 
                 if (will_write) {
-                        btrfs_fdatawrite_range(inode->i_mapping, pos,
-                                               pos + write_bytes - 1,
-                                               WB_SYNC_ALL);
+                        filemap_fdatawrite_range(inode->i_mapping, pos,
+                                                 pos + write_bytes - 1);
                 } else {
                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
                                                            num_pages);
@@ -1028,6 +1045,7 @@ out:
         mutex_unlock(&inode->i_mutex);
         if (ret)
                 err = ret;
+        btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 
 out_nolock:
         kfree(pages);
@@ -1068,8 +1086,10 @@ out_nolock:
                                         btrfs_end_transaction(trans, root);
                                 else
                                         btrfs_commit_transaction(trans, root);
-                        } else {
+                        } else if (ret != BTRFS_NO_LOG_SYNC) {
                                 btrfs_commit_transaction(trans, root);
+                        } else {
+                                btrfs_end_transaction(trans, root);
                         }
                 }
                 if (file->f_flags & O_DIRECT) {
@@ -1119,6 +1139,13 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
         int ret = 0;
         struct btrfs_trans_handle *trans;
 
+
+        /* we wait first, since the writeback may change the inode */
+        root->log_batch++;
+        /* the VFS called filemap_fdatawrite for us */
+        btrfs_wait_ordered_range(inode, 0, (u64)-1);
+        root->log_batch++;
+
         /*
          * check the transaction that last modified this inode
          * and see if its already been committed
@@ -1126,6 +1153,11 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
         if (!BTRFS_I(inode)->last_trans)
                 goto out;
 
+        /*
+         * if the last transaction that changed this file was before
+         * the current transaction, we can bail out now without any
+         * syncing
+         */
         mutex_lock(&root->fs_info->trans_mutex);
         if (BTRFS_I(inode)->last_trans <=
             root->fs_info->last_trans_committed) {
@@ -1135,13 +1167,6 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
         }
         mutex_unlock(&root->fs_info->trans_mutex);
 
-        root->log_batch++;
-        filemap_fdatawrite(inode->i_mapping);
-        btrfs_wait_ordered_range(inode, 0, (u64)-1);
-        root->log_batch++;
-
-        if (datasync && !(inode->i_state & I_DIRTY_PAGES))
-                goto out;
         /*
          * ok we haven't committed the transaction yet, lets do a commit
          */
@@ -1170,21 +1195,25 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
          */
         mutex_unlock(&dentry->d_inode->i_mutex);
 
-        if (ret > 0) {
-                ret = btrfs_commit_transaction(trans, root);
-        } else {
-                ret = btrfs_sync_log(trans, root);
-                if (ret == 0)
-                        ret = btrfs_end_transaction(trans, root);
-                else
+        if (ret != BTRFS_NO_LOG_SYNC) {
+                if (ret > 0) {
                         ret = btrfs_commit_transaction(trans, root);
+                } else {
+                        ret = btrfs_sync_log(trans, root);
+                        if (ret == 0)
+                                ret = btrfs_end_transaction(trans, root);
+                        else
+                                ret = btrfs_commit_transaction(trans, root);
+                }
+        } else {
+                ret = btrfs_end_transaction(trans, root);
         }
         mutex_lock(&dentry->d_inode->i_mutex);
 out:
         return ret > 0 ? EIO : ret;
 }
 
-static struct vm_operations_struct btrfs_file_vm_ops = {
+static const struct vm_operations_struct btrfs_file_vm_ops = {
         .fault          = filemap_fault,
         .page_mkwrite   = btrfs_page_mkwrite,
 };
@@ -1196,7 +1225,7 @@ static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
         return 0;
 }
 
-struct file_operations btrfs_file_operations = {
+const struct file_operations btrfs_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = do_sync_read,
         .aio_read       = generic_file_aio_read,