NTFS: Make ntfs_write_block() not instantiate sparse blocks if they are zero. (8dcdebaf) · Commits · e / devices / android_kernel_xiaomi_markw

fs/ntfs/ChangeLog

+2 −0

Original line number	Diff line number	Diff line
		@@ -77,6 +77,8 @@ ToDo/Notes:
		updating the times in the inode in ntfs_setattr().
		- Fixup handling of sparse, compressed, and encrypted attributes in
		fs/ntfs/inode.c::ntfs_read_locked_{,attr_,index_}inode().
		- Make ntfs_write_block() not instantiate sparse blocks if they contain
		only zeroes.

		2.1.23 - Implement extension of resident files and make writing safe as well as
		many bug fixes, cleanups, and enhancements...

+21 −0

Original line number	Diff line number	Diff line
		@@ -670,6 +670,27 @@ lock_retry_remap:
		}
		/* It is a hole, need to instantiate it. */
		if (lcn == LCN_HOLE) {
		u8 *kaddr;
		unsigned long bpos, bend;

		/* Check if the buffer is zero. */
		kaddr = kmap_atomic(page, KM_USER0);
		bpos = (unsigned long *)(kaddr + bh_offset(bh));
		bend = (unsigned long )((u8)bpos + blocksize);
		do {
		if (unlikely(*bpos))
		break;
		} while (likely(++bpos < bend));
		kunmap_atomic(kaddr, KM_USER0);
		if (bpos == bend) {
		/*
		* Buffer is zero and sparse, no need to write
		* it.
		*/
		bh->b_blocknr = -1;
		clear_buffer_dirty(bh);
		continue;
		}
		// TODO: Instantiate the hole.
		// clear_buffer_new(bh);
		// unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);