Return to xfs_vnode.c CVS log

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Switch from iget_locked to ilookup in vn_get.  We only want to
get the inode if it actually is present in core.  The new ilookup
function allows us to do this easily instead of having to tear down
the wrongly allocated inode again if it wasn't in memory.
Switch to ilookup.

/*
 * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.	 Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include <xfs.h>
#include <linux/pagemap.h>


uint64_t vn_generation;		/* vnode generation number */

spinlock_t	vnumber_lock = SPIN_LOCK_UNLOCKED;

/*
 * Dedicated vnode inactive/reclaim sync semaphores.
 * Prime number of hash buckets since address is used as the key.
 */
#define NVSYNC			37
#define vptosync(v)		(&vsync[((unsigned long)v) % NVSYNC])
sv_t vsync[NVSYNC];

/*
 * Translate stat(2) file types to vnode types and vice versa.
 * Aware of numeric order of S_IFMT and vnode type values.
 */
enum vtype iftovt_tab[] = {
	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VNON
};

u_short vttoif_tab[] = {
	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK, S_IFIFO, 0, S_IFSOCK
};

#define VN_LOCK(vp)		spin_lock(&(vp)->v_lock)
#define VN_UNLOCK(vp)		spin_unlock(&(vp)->v_lock)


void
vn_init(void)
{
	register sv_t *svp;
	register int i;

	for (svp = vsync, i = 0; i < NVSYNC; i++, svp++)
		init_sv(svp, SV_DEFAULT, "vsy", i);
}


/*
 * Clean a vnode of filesystem-specific data and prepare it for reuse.
 */
STATIC int
vn_reclaim(struct vnode *vp)
{
	int error;

	XFS_STATS_INC(xfsstats.vn_reclaim);

	vn_trace_entry(vp, "vn_reclaim", (inst_t *)__return_address);

	/*
	 * Only make the VOP_RECLAIM call if there are behaviors
	 * to call.
	 */
	if (vp->v_fbhv != NULL) {
		VOP_RECLAIM(vp, error);
		if (error)
			return -error;
	}
	ASSERT(vp->v_fbhv == NULL);

	VN_LOCK(vp);

	vp->v_flag &= (VRECLM|VWAIT);
	VN_UNLOCK(vp);

	vp->v_type = VNON;
	vp->v_fbhv = NULL;

#ifdef CONFIG_XFS_VNODE_TRACING
	ktrace_free(vp->v_trace);
	vp->v_trace = NULL;
#endif

	return 0;
}

STATIC void
vn_wakeup(struct vnode *vp)
{
	VN_LOCK(vp);
	if (vp->v_flag & VWAIT) {
		sv_broadcast(vptosync(vp));
	}
	vp->v_flag &= ~(VRECLM|VWAIT|VMODIFIED);
	VN_UNLOCK(vp);
}

int
vn_wait(struct vnode *vp)
{
	VN_LOCK(vp);
	if (vp->v_flag & (VINACT | VRECLM)) {
		vp->v_flag |= VWAIT;
		sv_wait(vptosync(vp), PINOD, &vp->v_lock, 0);
		return 1;
	}
	VN_UNLOCK(vp);
	return 0;
}

struct vnode *
vn_initialize(struct inode *inode)
{
	struct vnode	*vp = LINVFS_GET_VP(inode);

	XFS_STATS_INC(xfsstats.vn_active);

	vp->v_flag = VMODIFIED;
	spinlock_init(&vp->v_lock, "v_lock");

	spin_lock(&vnumber_lock);
	if (!++vn_generation)	/* v_number shouldn't be zero */
		vn_generation++;
	vp->v_number = vn_generation;
	spin_unlock(&vnumber_lock);

	ASSERT(VN_CACHED(vp) == 0);

	/* Initialize the first behavior and the behavior chain head. */
	vn_bhv_head_init(VN_BHV_HEAD(vp), "vnode");

#ifdef	CONFIG_XFS_VNODE_TRACING
	vp->v_trace = ktrace_alloc(VNODE_TRACE_SIZE, KM_SLEEP);
#endif	/* CONFIG_XFS_VNODE_TRACING */

	vn_trace_exit(vp, "vn_initialize", (inst_t *)__return_address);
	return vp;
}

/*
 * Get a reference on a vnode.
 */
vnode_t *
vn_get(struct vnode *vp, vmap_t *vmap)
{
	struct inode	*inode;

	XFS_STATS_INC(xfsstats.vn_get);
	inode = LINVFS_GET_IP(vp);
	if (inode->i_state & I_FREEING)
		return NULL;

	inode = ilookup(vmap->v_vfsp->vfs_super, vmap->v_ino);
	if (inode == NULL)		/* Inode not present */
		return NULL;

	vn_trace_exit(vp, "vn_get", (inst_t *)__return_address);
	ASSERT((vp->v_flag & VPURGE) == 0);

	return vp;
}

/*
 * "revalidate" the linux inode.
 */
int
vn_revalidate(struct vnode *vp)
{
	int		error;
	struct inode	*inode;
	vattr_t		va;

	vn_trace_entry(vp, "vn_revalidate", (inst_t *)__return_address);

	va.va_mask = AT_STAT|AT_GENCOUNT;

	ASSERT(vp->v_bh.bh_first != NULL);

	VOP_GETATTR(vp, &va, 0, NULL, error);

	if (! error) {
		inode = LINVFS_GET_IP(vp);
		ASSERT(inode);

		inode->i_mode	    = VTTOIF(va.va_type) | va.va_mode;
		inode->i_nlink	    = va.va_nlink;
		inode->i_uid	    = va.va_uid;
		inode->i_gid	    = va.va_gid;
		inode->i_size	    = va.va_size;
		inode->i_blocks	    = va.va_nblocks;
		inode->i_mtime	    = va.va_mtime.tv_sec;
		inode->i_ctime	    = va.va_ctime.tv_sec;
		inode->i_atime	    = va.va_atime.tv_sec;
		VUNMODIFY(vp);
	}

	return -error;
}


/*
 * purge a vnode from the cache
 * At this point the vnode is guaranteed to have no references (vn_count == 0)
 * The caller has to make sure that there are no ways someone could
 * get a handle (via vn_get) on the vnode (usually done via a mount/vfs lock).
 */
void
vn_purge(struct vnode *vp, vmap_t *vmap)
{
	vn_trace_entry(vp, "vn_purge", (inst_t *)__return_address);

	ASSERT(vp->v_flag & VPURGE);

again:
	/*
	 * Check whether vp has already been reclaimed since our caller
	 * sampled its version while holding a filesystem cache lock that
	 * its VOP_RECLAIM function acquires.
	 */
	VN_LOCK(vp);
	if (vp->v_number != vmap->v_number) {
		VN_UNLOCK(vp);
		return;
	}

	/*
	 * If vp is being reclaimed or inactivated, wait until it is inert,
	 * then proceed.  Can't assume that vnode is actually reclaimed
	 * just because the reclaimed flag is asserted -- a vn_alloc
	 * reclaim can fail.
	 */
	if (vp->v_flag & (VINACT | VRECLM)) {
		ASSERT(vn_count(vp) == 0);
		vp->v_flag |= VWAIT;
		sv_wait(vptosync(vp), PINOD, &vp->v_lock, 0);
		goto again;
	}

	/*
	 * Another process could have raced in and gotten this vnode...
	 */
	if (vn_count(vp) > 0) {
		VN_UNLOCK(vp);
		return;
	}

	XFS_STATS_DEC(xfsstats.vn_active);
	vp->v_flag |= VRECLM;
	VN_UNLOCK(vp);

	/*
	 * Call VOP_RECLAIM and clean vp. The FSYNC_INVAL flag tells
	 * vp's filesystem to flush and invalidate all cached resources.
	 * When vn_reclaim returns, vp should have no private data,
	 * either in a system cache or attached to v_data.
	 */
	if (vn_reclaim(vp) != 0)
		panic("vn_purge: cannot reclaim");

	/*
	 * Wakeup anyone waiting for vp to be reclaimed.
	 */
	vn_wakeup(vp);
}

/*
 * Add a reference to a referenced vnode.
 */
struct vnode *
vn_hold(struct vnode *vp)
{
	struct inode *inode;

	XFS_STATS_INC(xfsstats.vn_hold);

	VN_LOCK(vp);
	inode = igrab(LINVFS_GET_IP(vp));
	ASSERT(inode);
	VN_UNLOCK(vp);

	return vp;
}

/*
 *  Call VOP_INACTIVE on last reference.
 */
void
vn_rele(struct vnode *vp)
{
	int	vcnt;
	/* REFERENCED */
	int cache;

	XFS_STATS_INC(xfsstats.vn_rele);


	VN_LOCK(vp);

	vn_trace_entry(vp, "vn_rele", (inst_t *)__return_address);
	vcnt = vn_count(vp);

	/*
	 * Since we always get called from put_inode we know
	 * that i_count won't be decremented after we
	 * return.
	 */
	if (vcnt == 0) {
		/*
		 * As soon as we turn this on, noone can find us in vn_get
		 * until we turn off VINACT or VRECLM
		 */
		vp->v_flag |= VINACT;
		VN_UNLOCK(vp);

		/*
		 * Do not make the VOP_INACTIVE call if there
		 * are no behaviors attached to the vnode to call.
		 */
		if (vp->v_fbhv != NULL) {
			VOP_INACTIVE(vp, NULL, cache);
		}

		VN_LOCK(vp);
		if (vp->v_flag & VWAIT) {
			if (vp->v_flag & VWAIT) {
				sv_broadcast(vptosync(vp));
			}
		}

		vp->v_flag &= ~(VINACT|VWAIT|VRECLM|VMODIFIED);

	}

	VN_UNLOCK(vp);

	vn_trace_exit(vp, "vn_rele", (inst_t *)__return_address);
}


/*
 * Finish the removal of a vnode.
 */
void
vn_remove(struct vnode *vp)
{
	/* REFERENCED */
	vmap_t	vmap;

	/* Make sure we don't do this to the same vnode twice */
	if (!(vp->v_fbhv))
		return;

	XFS_STATS_INC(xfsstats.vn_remove);

	vn_trace_exit(vp, "vn_remove", (inst_t *)__return_address);

	/*
	 * After the following purge the vnode
	 * will no longer exist.
	 */
	VMAP(vp, vmap);
	vn_purge(vp, &vmap);
}


#ifdef	CONFIG_XFS_VNODE_TRACING

#define KTRACE_ENTER(vp, vk, s, line, ra)			\
	ktrace_enter(	(vp)->v_trace,				\
/*  0 */		(void *)(__psint_t)(vk),		\
/*  1 */		(void *)(s),				\
/*  2 */		(void *)(__psint_t) line,		\
/*  3 */		(void *)(vn_count(vp)), \
/*  4 */		(void *)(ra),				\
/*  5 */		(void *)(__psunsigned_t)(vp)->v_flag,	\
/*  6 */		(void *)(__psint_t)smp_processor_id(),	\
/*  7 */		(void *)(__psint_t)(current->pid),	\
/*  8 */		(void *)__return_address,		\
/*  9 */		0, 0, 0, 0, 0, 0, 0)

/*
 * Vnode tracing code.
 */
void
vn_trace_entry(vnode_t *vp, char *func, inst_t *ra)
{
	KTRACE_ENTER(vp, VNODE_KTRACE_ENTRY, func, 0, ra);
}

void
vn_trace_exit(vnode_t *vp, char *func, inst_t *ra)
{
	KTRACE_ENTER(vp, VNODE_KTRACE_EXIT, func, 0, ra);
}

void
vn_trace_hold(vnode_t *vp, char *file, int line, inst_t *ra)
{
	KTRACE_ENTER(vp, VNODE_KTRACE_HOLD, file, line, ra);
}

void
vn_trace_ref(vnode_t *vp, char *file, int line, inst_t *ra)
{
	KTRACE_ENTER(vp, VNODE_KTRACE_REF, file, line, ra);
}

void
vn_trace_rele(vnode_t *vp, char *file, int line, inst_t *ra)
{
	KTRACE_ENTER(vp, VNODE_KTRACE_RELE, file, line, ra);
}
#endif	/* CONFIG_XFS_VNODE_TRACING */