Commit 7aa91e10 authored Oct 16, 2007 by Ken Chen Committed by Linus Torvalds Oct 16, 2007

hugetlb: allow extending ftruncate on hugetlbfs



For historical reason, expanding ftruncate that increases file size on
hugetlbfs is not allowed due to pages were pre-faulted and lack of fault
handler.  Now that we have demand faulting on hugetlb since 2.6.15, there
is no reason to hold back that limitation.

This will make hugetlbfs behave more like a normal fs.  I'm writing a user
level code that uses hugetlbfs but will fall back to tmpfs if there are no
hugetlb page available in the system.  Having hugetlbfs specific ftruncate
behavior is a bit quirky and I would like to remove that artificial
limitation.

Signed-off-by:  <kenchen@google.com>
Acked-by: Wiliam Irwin <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 54f9f80d

fs/hugetlbfs/inode.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -322,21 +322,15 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
		}
		}

		/*
		* Expanding truncates are not allowed.
		*/
		static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
		{
		pgoff_t pgoff;
		struct address_space *mapping = inode->i_mapping;

		if (offset > inode->i_size)
		return -EINVAL;

		BUG_ON(offset & ~HPAGE_MASK);
		pgoff = offset >> PAGE_SHIFT;

		inode->i_size = offset;
		i_size_write(inode, offset);
		spin_lock(&mapping->i_mmap_lock);
		if (!prio_tree_empty(&mapping->i_mmap))
		hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);

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