2 files changed, 74 insertions, 64 deletions

diff --git a/fs/sync.c b/fs/sync.c
index b54e0541ad89..01e82170545a 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -234,58 +234,10 @@ SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
         return do_fsync(fd, 1);
 }
 
-/*
- * sys_sync_file_range() permits finely controlled syncing over a segment of
- * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
- * zero then sys_sync_file_range() will operate from offset out to EOF.
- *
- * The flag bits are:
- *
- * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
- * before performing the write.
- *
- * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
- * range which are not presently under writeback. Note that this may block for
- * significant periods due to exhaustion of disk request structures.
- *
- * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
- * after performing the write.
- *
- * Useful combinations of the flag bits are:
- *
- * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
- * in the range which were dirty on entry to sys_sync_file_range() are placed
- * under writeout.  This is a start-write-for-data-integrity operation.
- *
- * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
- * are not presently under writeout.  This is an asynchronous flush-to-disk
- * operation.  Not suitable for data integrity operations.
- *
- * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
- * completion of writeout of all pages in the range.  This will be used after an
- * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
- * for that operation to complete and to return the result.
- *
- * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
- * a traditional sync() operation.  This is a write-for-data-integrity operation
- * which will ensure that all pages in the range which were dirty on entry to
- * sys_sync_file_range() are committed to disk.
- *
- *
- * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
- * I/O errors or ENOSPC conditions and will return those to the caller, after
- * clearing the EIO and ENOSPC flags in the address_space.
- *
- * It should be noted that none of these operations write out the file's
- * metadata.  So unless the application is strictly performing overwrites of
- * already-instantiated disk blocks, there are no guarantees here that the data
- * will be available after a crash.
- */
-int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
-                         unsigned int flags)
+int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
+                    unsigned int flags)
 {
         int ret;
-        struct fd f;
         struct address_space *mapping;
         loff_t endbyte;                 /* inclusive */
         umode_t i_mode;
@@ -325,41 +277,96 @@ int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
         else
                 endbyte--;              /* inclusive */
 
-        ret = -EBADF;
-        f = fdget(fd);
-        if (!f.file)
-                goto out;
-
-        i_mode = file_inode(f.file)->i_mode;
+        i_mode = file_inode(file)->i_mode;
         ret = -ESPIPE;
         if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
                         !S_ISLNK(i_mode))
-                goto out_put;
+                goto out;
 
-        mapping = f.file->f_mapping;
+        mapping = file->f_mapping;
         ret = 0;
         if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
-                ret = file_fdatawait_range(f.file, offset, endbyte);
+                ret = file_fdatawait_range(file, offset, endbyte);
                 if (ret < 0)
-                        goto out_put;
+                        goto out;
         }
 
         if (flags & SYNC_FILE_RANGE_WRITE) {
                 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
                                                  WB_SYNC_NONE);
                 if (ret < 0)
-                        goto out_put;
+                        goto out;
         }
 
         if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
-                ret = file_fdatawait_range(f.file, offset, endbyte);
+                ret = file_fdatawait_range(file, offset, endbyte);
 
-out_put:
-        fdput(f);
 out:
         return ret;
 }
 
+/*
+ * sys_sync_file_range() permits finely controlled syncing over a segment of
+ * a file in the range offset .. (offset+nbytes-1) inclusive.  If nbytes is
+ * zero then sys_sync_file_range() will operate from offset out to EOF.
+ *
+ * The flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
+ * before performing the write.
+ *
+ * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
+ * range which are not presently under writeback. Note that this may block for
+ * significant periods due to exhaustion of disk request structures.
+ *
+ * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
+ * after performing the write.
+ *
+ * Useful combinations of the flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
+ * in the range which were dirty on entry to sys_sync_file_range() are placed
+ * under writeout.  This is a start-write-for-data-integrity operation.
+ *
+ * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
+ * are not presently under writeout.  This is an asynchronous flush-to-disk
+ * operation.  Not suitable for data integrity operations.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
+ * completion of writeout of all pages in the range.  This will be used after an
+ * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
+ * for that operation to complete and to return the result.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
+ * a traditional sync() operation.  This is a write-for-data-integrity operation
+ * which will ensure that all pages in the range which were dirty on entry to
+ * sys_sync_file_range() are committed to disk.
+ *
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
+ * I/O errors or ENOSPC conditions and will return those to the caller, after
+ * clearing the EIO and ENOSPC flags in the address_space.
+ *
+ * It should be noted that none of these operations write out the file's
+ * metadata.  So unless the application is strictly performing overwrites of
+ * already-instantiated disk blocks, there are no guarantees here that the data
+ * will be available after a crash.
+ */
+int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+                         unsigned int flags)
+{
+        int ret;
+        struct fd f;
+
+        ret = -EBADF;
+        f = fdget(fd);
+        if (f.file)
+                ret = sync_file_range(f.file, offset, nbytes, flags);
+
+        fdput(f);
+        return ret;
+}
+
 SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
                                 unsigned int, flags)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd28e7679089..2f66e247ecba 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2785,6 +2785,9 @@ extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
                            int datasync);
 extern int vfs_fsync(struct file *file, int datasync);
 
+extern int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,
+                                unsigned int flags);
+
 /*
  * Sync the bytes written if this was a synchronous write.  Expect ki_pos
  * to already be updated for the write, and will return either the amount