Commit 3a7ed3ff authored Jan 08, 2015 by Omar Sandoval Committed by Trond Myklebust Jan 30, 2015

nfs: prevent truncate on active swapfile

Most filesystems prevent truncation of an active swapfile by way of
inode_newsize_ok, called from inode_change_ok. NFS doesn't call either
from nfs_setattr, presumably because most of these checks are expected
to be done server-side. However, the IS_SWAPFILE check can only be done
client-side, and truncating a swapfile can't possibly be good.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

parent 6ffa30d3

fs/nfs/inode.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -507,10 +507,15 @@ nfs_setattr(struct dentry dentry, struct iattr attr)
		attr->ia_valid &= ~ATTR_MODE;

		if (attr->ia_valid & ATTR_SIZE) {
		loff_t i_size;

		BUG_ON(!S_ISREG(inode->i_mode));

		if (attr->ia_size == i_size_read(inode))
		i_size = i_size_read(inode);
		if (attr->ia_size == i_size)
		attr->ia_valid &= ~ATTR_SIZE;
		else if (attr->ia_size < i_size && IS_SWAPFILE(inode))
		return -ETXTBSY;
		}

		/* Optimization: if the end result is no change, don't RPC */

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