Commit 072bd7ea authored May 23, 2011 by Theodore Ts'o

ext4: use truncate_setsize() unconditionally

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" <tytso@mit.edu>

parent 28e35e42

fs/ext4/inode.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -5309,8 +5309,7 @@ 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);
		@@ -5344,14 +5343,15 @@ 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);