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Commit 3a7ed3ff authored by Omar Sandoval's avatar Omar Sandoval Committed by Trond Myklebust
Browse files

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: default avatarOmar Sandoval <osandov@osandov.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 6ffa30d3

fs/nfs/inode.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -507,10 +507,15 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr) 
		attr->ia_valid &= ~ATTR_MODE;

		attr->ia_valid &= ~ATTR_MODE;





	if (attr->ia_valid & ATTR_SIZE) {

	if (attr->ia_valid & ATTR_SIZE) {

		loff_t i_size;



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

		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;

			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 */

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