diff options
| -rw-r--r-- | fs/ntfs/ChangeLog | 2 | ||||
| -rw-r--r-- | fs/ntfs/aops.c | 21 |
2 files changed, 23 insertions, 0 deletions
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog index ed8d00150931..b1766642baf8 100644 --- a/fs/ntfs/ChangeLog +++ b/fs/ntfs/ChangeLog @@ -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... diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c index 78adad7a988d..f3ad36d8b8c9 100644 --- a/fs/ntfs/aops.c +++ b/fs/ntfs/aops.c @@ -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); |