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>
This commit is contained in:
Omar Sandoval 2015-01-08 01:18:30 -08:00 committed by Trond Myklebust
parent 6ffa30d3f7
commit 3a7ed3fff3

View file

@ -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 */