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Commit a564b8f0 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

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: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarRik 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 29418aa4

fs/nfs/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -86,6 +86,14 @@ config NFS_V4 


	  If unsure, say Y.



config NFS_SWAP

	bool "Provide swap over NFS support"

	default n

	depends on NFS_FS

	select SUNRPC_SWAP

	help

	  This option enables swapon to work on files located on NFS mounts.



config NFS_V4_1

	bool "NFS client support for NFSv4.1 (EXPERIMENTAL)"

	depends on NFS_V4 && EXPERIMENTAL

fs/nfs/direct.c

+54 −28
Original line number Diff line number Diff line
@@ -115,17 +115,28 @@ static inline int put_dreq(struct nfs_direct_req *dreq) 
 * @nr_segs: size of iovec array

 *

 * The presence of this routine in the address space ops vector means

 * the NFS client supports direct I/O.  However, we shunt off direct

 * read and write requests before the VFS gets them, so this method

 * should never be called.

 * the NFS client supports direct I/O. However, for most direct IO, we

 * shunt off direct read and write requests before the VFS gets them,

 * so this method is only ever called for swap.

 */

ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)

{

#ifndef CONFIG_NFS_SWAP

	dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",

			iocb->ki_filp->f_path.dentry->d_name.name,

			(long long) pos, nr_segs);



	return -EINVAL;

#else

	VM_BUG_ON(iocb->ki_left != PAGE_SIZE);

	VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);



	if (rw == READ || rw == KERNEL_READ)

		return nfs_file_direct_read(iocb, iov, nr_segs, pos,

				rw == READ ? true : false);

	return nfs_file_direct_write(iocb, iov, nr_segs, pos,

				rw == WRITE ? true : false);

#endif /* CONFIG_NFS_SWAP */

}



static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
@@ -303,7 +314,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { 
 */

static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc,

						const struct iovec *iov,

						loff_t pos)

						loff_t pos, bool uio)

{

	struct nfs_direct_req *dreq = desc->pg_dreq;

	struct nfs_open_context *ctx = dreq->ctx;
@@ -331,12 +342,20 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de 
					  GFP_KERNEL);

		if (!pagevec)

			break;

		if (uio) {

			down_read(&current->mm->mmap_sem);

			result = get_user_pages(current, current->mm, user_addr,

					npages, 1, 0, pagevec, NULL);

			up_read(&current->mm->mmap_sem);

			if (result < 0)

				break;

		} else {

			WARN_ON(npages != 1);

			result = get_kernel_page(user_addr, 1, pagevec);

			if (WARN_ON(result != 1))

				break;

		}



		if ((unsigned)result < npages) {

			bytes = result * PAGE_SIZE;

			if (bytes <= pgbase) {
@@ -386,7 +405,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de 
static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,

					      const struct iovec *iov,

					      unsigned long nr_segs,

					      loff_t pos)

					      loff_t pos, bool uio)

{

	struct nfs_pageio_descriptor desc;

	ssize_t result = -EINVAL;
@@ -400,7 +419,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 


	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *vec = &iov[seg];

		result = nfs_direct_read_schedule_segment(&desc, vec, pos);

		result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio);

		if (result < 0)

			break;

		requested_bytes += result;
@@ -426,7 +445,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 
}



static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,

			       unsigned long nr_segs, loff_t pos)

			       unsigned long nr_segs, loff_t pos, bool uio)

{

	ssize_t result = -ENOMEM;

	struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -444,7 +463,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, 
	if (!is_sync_kiocb(iocb))

		dreq->iocb = iocb;



	result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos);

	result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);

	if (!result)

		result = nfs_direct_wait(dreq);

	NFS_I(inode)->read_io += result;
@@ -610,7 +629,7 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode 
 */

static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc,

						 const struct iovec *iov,

						 loff_t pos)

						 loff_t pos, bool uio)

{

	struct nfs_direct_req *dreq = desc->pg_dreq;

	struct nfs_open_context *ctx = dreq->ctx;
@@ -638,12 +657,19 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *d 
		if (!pagevec)

			break;



		if (uio) {

			down_read(&current->mm->mmap_sem);

			result = get_user_pages(current, current->mm, user_addr,

						npages, 0, 0, pagevec, NULL);

			up_read(&current->mm->mmap_sem);

			if (result < 0)

				break;

		} else {

			WARN_ON(npages != 1);

			result = get_kernel_page(user_addr, 0, pagevec);

			if (WARN_ON(result != 1))

				break;

		}



		if ((unsigned)result < npages) {

			bytes = result * PAGE_SIZE;
@@ -774,7 +800,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { 
static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,

					       const struct iovec *iov,

					       unsigned long nr_segs,

					       loff_t pos)

					       loff_t pos, bool uio)

{

	struct nfs_pageio_descriptor desc;

	struct inode *inode = dreq->inode;
@@ -790,7 +816,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, 


	for (seg = 0; seg < nr_segs; seg++) {

		const struct iovec *vec = &iov[seg];

		result = nfs_direct_write_schedule_segment(&desc, vec, pos);

		result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio);

		if (result < 0)

			break;

		requested_bytes += result;
@@ -818,7 +844,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, 


static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,

				unsigned long nr_segs, loff_t pos,

				size_t count)

				size_t count, bool uio)

{

	ssize_t result = -ENOMEM;

	struct inode *inode = iocb->ki_filp->f_mapping->host;
@@ -836,7 +862,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, 
	if (!is_sync_kiocb(iocb))

		dreq->iocb = iocb;



	result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos);

	result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, uio);

	if (!result)

		result = nfs_direct_wait(dreq);

out_release:
@@ -867,7 +893,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, 
 * cache.

 */

ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,

				unsigned long nr_segs, loff_t pos)

				unsigned long nr_segs, loff_t pos, bool uio)

{

	ssize_t retval = -EINVAL;

	struct file *file = iocb->ki_filp;
@@ -892,7 +918,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, 


	task_io_account_read(count);



	retval = nfs_direct_read(iocb, iov, nr_segs, pos);

	retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio);

	if (retval > 0)

		iocb->ki_pos = pos + retval;
@@ -923,7 +949,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, 
 * is no atomic O_APPEND write facility in the NFS protocol.

 */

ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,

				unsigned long nr_segs, loff_t pos)

				unsigned long nr_segs, loff_t pos, bool uio)

{

	ssize_t retval = -EINVAL;

	struct file *file = iocb->ki_filp;
@@ -955,7 +981,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, 


	task_io_account_write(count);



	retval = nfs_direct_write(iocb, iov, nr_segs, pos, count);

	retval = nfs_direct_write(iocb, iov, nr_segs, pos, count, uio);

	if (retval > 0) {

		struct inode *inode = mapping->host;

fs/nfs/file.c

+20 −2
Original line number Diff line number Diff line
@@ -175,7 +175,7 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov, 
	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 @@ static int nfs_launder_page(struct page *page) 
	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 @@ const struct address_space_operations nfs_file_aops = { 
	.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 @@ ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, 
	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,

include/linux/nfs_fs.h

+2 −2
Original line number Diff line number Diff line
@@ -473,10 +473,10 @@ extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t, 
			unsigned long);

extern ssize_t nfs_file_direct_read(struct kiocb *iocb,

			const struct iovec *iov, unsigned long nr_segs,

			loff_t pos);

			loff_t pos, bool uio);

extern ssize_t nfs_file_direct_write(struct kiocb *iocb,

			const struct iovec *iov, unsigned long nr_segs,

			loff_t pos);

			loff_t pos, bool uio);



/*

 * linux/fs/nfs/dir.c

include/linux/sunrpc/xprt.h

+3 −0
Original line number Diff line number Diff line
@@ -174,6 +174,8 @@ struct rpc_xprt { 
	unsigned long		state;		/* transport state */

	unsigned char		shutdown   : 1,	/* being shut down */

				resvport   : 1; /* use a reserved port */

	unsigned int		swapper;	/* we're swapping over this

						   transport */

	unsigned int		bind_index;	/* bind function index */



	/*
@@ -316,6 +318,7 @@ void xprt_release_rqst_cong(struct rpc_task *task); 
void			xprt_disconnect_done(struct rpc_xprt *xprt);

void			xprt_force_disconnect(struct rpc_xprt *xprt);

void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);

int			xs_swapper(struct rpc_xprt *xprt, int enable);



/*

 * Reserved bit positions in xprt->state