nfs: enable swap on NFS
Implement the new swapfile a_ops for NFS and hook up ->direct_IO. This
will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under
PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol
->connect() method.
PF_MEMALLOC should allow the allocation of struct socket and related
objects and the early (re)setting of SOCK_MEMALLOC should allow us to
receive the packets required for the TCP connection buildup.
[jlayton@redhat.com: Restore PF_MEMALLOC task flags in all cases]
[dfeng@redhat.com: Fix handling of multiple swap files]
[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index acd4e4c..50fb83a8 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -175,7 +175,7 @@
ssize_t result;
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_read(iocb, iov, nr_segs, pos);
+ return nfs_file_direct_read(iocb, iov, nr_segs, pos, true);
dprintk("NFS: read(%s/%s, %lu@%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
@@ -482,6 +482,20 @@
return nfs_wb_page(inode, page);
}
+#ifdef CONFIG_NFS_SWAP
+static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
+ sector_t *span)
+{
+ *span = sis->pages;
+ return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 1);
+}
+
+static void nfs_swap_deactivate(struct file *file)
+{
+ xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 0);
+}
+#endif
+
const struct address_space_operations nfs_file_aops = {
.readpage = nfs_readpage,
.readpages = nfs_readpages,
@@ -496,6 +510,10 @@
.migratepage = nfs_migrate_page,
.launder_page = nfs_launder_page,
.error_remove_page = generic_error_remove_page,
+#ifdef CONFIG_NFS_SWAP
+ .swap_activate = nfs_swap_activate,
+ .swap_deactivate = nfs_swap_deactivate,
+#endif
};
/*
@@ -570,7 +588,7 @@
size_t count = iov_length(iov, nr_segs);
if (iocb->ki_filp->f_flags & O_DIRECT)
- return nfs_file_direct_write(iocb, iov, nr_segs, pos);
+ return nfs_file_direct_write(iocb, iov, nr_segs, pos, true);
dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,