Commit e5e94017 authored by Benny Halevy's avatar Benny Halevy Committed by Trond Myklebust
Browse files

NFS: create and destroy inode's layout cache 



At the start of the io paths, try to grab the relevant layout
information.  This will initiate the inode's layout cache, but
stubs ensure the cache stays empty.

Signed-off-by: default avatarBenny Halevy <bhalevy@panasas.com>
Signed-off-by: default avatarDean Hildebrand <dhildebz@umich.edu>
Signed-off-by: default avatarMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: default avatarTao Guo <guotao@nrchpc.ac.cn>
Signed-off-by: default avatarRicardo Labiaga <ricardo.labiaga@netapp.com>
Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: default avatarAndy Adamson <andros@netapp.com>
Signed-off-by: default avatarFred Isaman <iisaman@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 7ab672ce

fs/nfs/file.c

+5 −0
Original line number Diff line number Diff line
@@ -36,6 +36,7 @@ 
#include "internal.h"

#include "iostat.h"

#include "fscache.h"

#include "pnfs.h"



#define NFSDBG_FACILITY		NFSDBG_FILE
@@ -386,6 +387,10 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping, 
		file->f_path.dentry->d_name.name,

		mapping->host->i_ino, len, (long long) pos);



	pnfs_update_layout(mapping->host,

			   nfs_file_open_context(file),

			   IOMODE_RW);



start:

	/*

	 * Prevent starvation issues if someone is doing a consistency

fs/nfs/inode.c

+3 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ 
#include "internal.h"

#include "fscache.h"

#include "dns_resolve.h"

#include "pnfs.h"



#define NFSDBG_FACILITY		NFSDBG_VFS
@@ -1410,6 +1411,7 @@ void nfs4_evict_inode(struct inode *inode) 
{

	truncate_inode_pages(&inode->i_data, 0);

	end_writeback(inode);

	pnfs_destroy_layout(NFS_I(inode));

	/* If we are holding a delegation, return it! */

	nfs_inode_return_delegation_noreclaim(inode);

	/* First call standard NFS clear_inode() code */
@@ -1447,6 +1449,7 @@ static inline void nfs4_init_once(struct nfs_inode *nfsi) 
	nfsi->delegation = NULL;

	nfsi->delegation_state = 0;

	init_rwsem(&nfsi->rwsem);

	nfsi->layout = NULL;

#endif

}

fs/nfs/pnfs.c

+140 −0
Original line number Diff line number Diff line
@@ -166,3 +166,143 @@ pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type) 
	spin_unlock(&pnfs_spinlock);

}

EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);



static void

get_layout_hdr_locked(struct pnfs_layout_hdr *lo)

{

	assert_spin_locked(&lo->inode->i_lock);

	lo->refcount++;

}



static void

put_layout_hdr_locked(struct pnfs_layout_hdr *lo)

{

	assert_spin_locked(&lo->inode->i_lock);

	BUG_ON(lo->refcount == 0);



	lo->refcount--;

	if (!lo->refcount) {

		dprintk("%s: freeing layout cache %p\n", __func__, lo);

		NFS_I(lo->inode)->layout = NULL;

		kfree(lo);

	}

}



void

pnfs_destroy_layout(struct nfs_inode *nfsi)

{

	struct pnfs_layout_hdr *lo;



	spin_lock(&nfsi->vfs_inode.i_lock);

	lo = nfsi->layout;

	if (lo) {

		/* Matched by refcount set to 1 in alloc_init_layout_hdr */

		put_layout_hdr_locked(lo);

	}

	spin_unlock(&nfsi->vfs_inode.i_lock);

}



/* STUB - pretend LAYOUTGET to server failed */

static struct pnfs_layout_segment *

send_layoutget(struct pnfs_layout_hdr *lo,

	   struct nfs_open_context *ctx,

	   u32 iomode)

{

	struct inode *ino = lo->inode;



	set_bit(lo_fail_bit(iomode), &lo->state);

	spin_lock(&ino->i_lock);

	put_layout_hdr_locked(lo);

	spin_unlock(&ino->i_lock);

	return NULL;

}



static struct pnfs_layout_hdr *

alloc_init_layout_hdr(struct inode *ino)

{

	struct pnfs_layout_hdr *lo;



	lo = kzalloc(sizeof(struct pnfs_layout_hdr), GFP_KERNEL);

	if (!lo)

		return NULL;

	lo->refcount = 1;

	lo->inode = ino;

	return lo;

}



static struct pnfs_layout_hdr *

pnfs_find_alloc_layout(struct inode *ino)

{

	struct nfs_inode *nfsi = NFS_I(ino);

	struct pnfs_layout_hdr *new = NULL;



	dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);



	assert_spin_locked(&ino->i_lock);

	if (nfsi->layout)

		return nfsi->layout;



	spin_unlock(&ino->i_lock);

	new = alloc_init_layout_hdr(ino);

	spin_lock(&ino->i_lock);



	if (likely(nfsi->layout == NULL))	/* Won the race? */

		nfsi->layout = new;

	else

		kfree(new);

	return nfsi->layout;

}



/* STUB - LAYOUTGET never succeeds, so cache is empty */

static struct pnfs_layout_segment *

pnfs_has_layout(struct pnfs_layout_hdr *lo, u32 iomode)

{

	return NULL;

}



/*

 * Layout segment is retreived from the server if not cached.

 * The appropriate layout segment is referenced and returned to the caller.

 */

struct pnfs_layout_segment *

pnfs_update_layout(struct inode *ino,

		   struct nfs_open_context *ctx,

		   enum pnfs_iomode iomode)

{

	struct nfs_inode *nfsi = NFS_I(ino);

	struct pnfs_layout_hdr *lo;

	struct pnfs_layout_segment *lseg = NULL;



	if (!pnfs_enabled_sb(NFS_SERVER(ino)))

		return NULL;

	spin_lock(&ino->i_lock);

	lo = pnfs_find_alloc_layout(ino);

	if (lo == NULL) {

		dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__);

		goto out_unlock;

	}



	/* Check to see if the layout for the given range already exists */

	lseg = pnfs_has_layout(lo, iomode);

	if (lseg) {

		dprintk("%s: Using cached lseg %p for iomode %d)\n",

			__func__, lseg, iomode);

		goto out_unlock;

	}



	/* if LAYOUTGET already failed once we don't try again */

	if (test_bit(lo_fail_bit(iomode), &nfsi->layout->state))

		goto out_unlock;



	get_layout_hdr_locked(lo);

	spin_unlock(&ino->i_lock);



	lseg = send_layoutget(lo, ctx, iomode);

out:

	dprintk("%s end, state 0x%lx lseg %p\n", __func__,

		nfsi->layout->state, lseg);

	return lseg;

out_unlock:

	spin_unlock(&ino->i_lock);

	goto out;

}

fs/nfs/pnfs.h

+39 −0
Original line number Diff line number Diff line
@@ -34,6 +34,11 @@ 


#define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"



enum {

	NFS_LAYOUT_RO_FAILED = 0,	/* get ro layout failed stop trying */

	NFS_LAYOUT_RW_FAILED,		/* get rw layout failed stop trying */

};



/* Per-layout driver specific registration structure */

struct pnfs_layoutdriver_type {

	struct list_head pnfs_tblid;
@@ -44,14 +49,48 @@ struct pnfs_layoutdriver_type { 
	int (*uninitialize_mountpoint) (struct nfs_server *);

};



struct pnfs_layout_hdr {

	unsigned long		refcount;

	unsigned long		state;

	struct inode		*inode;

};



extern int pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *);

extern void pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *);



struct pnfs_layout_segment *

pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,

		   enum pnfs_iomode access_type);

void set_pnfs_layoutdriver(struct nfs_server *, u32 id);

void unset_pnfs_layoutdriver(struct nfs_server *);

void pnfs_destroy_layout(struct nfs_inode *);





static inline int lo_fail_bit(u32 iomode)

{

	return iomode == IOMODE_RW ?

			 NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;

}



/* Return true if a layout driver is being used for this mountpoint */

static inline int pnfs_enabled_sb(struct nfs_server *nfss)

{

	return nfss->pnfs_curr_ld != NULL;

}



#else  /* CONFIG_NFS_V4_1 */



static inline void pnfs_destroy_layout(struct nfs_inode *nfsi)

{

}



static inline struct pnfs_layout_segment *

pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,

		   enum pnfs_iomode access_type)

{

	return NULL;

}



static inline void set_pnfs_layoutdriver(struct nfs_server *s, u32 id)

{

}

fs/nfs/read.c

+3 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include "internal.h"

#include "iostat.h"

#include "fscache.h"

#include "pnfs.h"



#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
@@ -120,6 +121,7 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, 
	len = nfs_page_length(page);

	if (len == 0)

		return nfs_return_empty_page(page);

	pnfs_update_layout(inode, ctx, IOMODE_READ);

	new = nfs_create_request(ctx, inode, page, 0, len);

	if (IS_ERR(new)) {

		unlock_page(page);
@@ -624,6 +626,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping, 
	if (ret == 0)

		goto read_complete; /* all pages were read */



	pnfs_update_layout(inode, desc.ctx, IOMODE_READ);

	if (rsize < PAGE_CACHE_SIZE)

		nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);

	else