Re: [PATCH 1/5] fallocate() implementation in i86, x86_64 and powerpc

On Thu, May 03, 2007 at 09:29:55PM -0700, Andrew Morton wrote:

On Thu, 26 Apr 2007 23:33:32 +0530 "Amit K. Arora" [off-list ref] wrote:

quoted

This patch implements the fallocate() system call and adds support for
i386, x86_64 and powerpc.

...
+{
+	struct file *file;
+	struct inode *inode;
+	long ret = -EINVAL;
+
+	if (len == 0 || offset < 0)
+		goto out;

The posix spec implies that negative `len' is permitted - presumably "allocate
ahead of `offset'".  How peculiar.

I just checked the man page for posix_fallocate() and it says:

      EINVAL  offset or len was less than zero.

We should probably follow this lead.

quoted

+
+	ret = -ENODEV;
+	if (!S_ISREG(inode->i_mode))
+		goto out_fput;

So we return ENODEV against an S_ISBLK fd, as per the posix spec.  That
seems a bit silly of them.

Hmmmm - I thought that the intention of sys_fallocate() was to
be generic enough to eventually allow preallocation on directories.
If that is the case, then this check will prevent that....

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group