From: Theodore Ts'o Subject: [PATCH -v2] ext4: use truncate_setsize() unconditionally Date: Mon, 23 May 2011 15:19:01 -0400 Message-ID: <1306178341-17632-1-git-send-email-tytso@mit.edu> References: Cc: jiayingz@google.com, Theodore Ts'o To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:49577 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933001Ab1EWTTF (ORCPT ); Mon, 23 May 2011 15:19:05 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: In commit c8d46e41 (ext4: Add flag to files with blocks intentionally past EOF), if the EOFBLOCKS_FL flag is set, we call ext4_truncate() before calling vmtruncate(). This caused any allocated but unwritten blocks created by calling fallocate() with the FALLOC_FL_KEEP_SIZE flag to be dropped. This was done to make to make sure that EOFBLOCKS_FL would not be cleared while still leaving blocks past i_size allocated. This was not necessary, since ext4_truncate() guarantees that blocks past i_size will be dropped, even in the case where truncate() has increased i_size before calling ext4_truncate(). So fix this by removing the EOFBLOCKS_FL special case treatment in ext4_setattr(). In addition, use truncate_setsize() followed by a call to ext4_truncate() instead of using vmtruncate(). This is more efficient since it skips the call to inode_newsize_ok(), which has been checked already by inode_change_ok(). This is also in a win in the case where EOFBLOCKS_FL is set since it avoids calling ext4_truncate() twice. Signed-off-by: "Theodore Ts'o" --- Jiayingz pointed out that in the case where we fallocate 12k, write 4k, and then truncate to 4k, we should discard the excess fallocate'd blocks. So if attr->ia_size == inode.i_size, we can skip the truncate_setsize() call, but if the EOFBLOCKS_FL flag is set, we should still call ext4_truncate(). fs/ext4/inode.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index df3fb20..2e95819 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5363,8 +5363,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) if (S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE && - (attr->ia_size < inode->i_size || - (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) { + (attr->ia_size < inode->i_size)) { handle_t *handle; handle = ext4_journal_start(inode, 3); @@ -5398,14 +5397,15 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) goto err_out; } } - /* ext4_truncate will clear the flag */ - if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) - ext4_truncate(inode); } - if ((attr->ia_valid & ATTR_SIZE) && - attr->ia_size != i_size_read(inode)) - rc = vmtruncate(inode, attr->ia_size); + if (attr->ia_valid & ATTR_SIZE) { + if (attr->ia_size != i_size_read(inode)) { + truncate_setsize(inode, attr->ia_size); + ext4_truncate(inode); + } else if (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)) + ext4_truncate(inode); + } if (!rc) { setattr_copy(inode, attr); -- 1.7.3.1