patch-2.4.25 linux-2.4.25/fs/xfs/xfs_iget.c

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diff -urN linux-2.4.24/fs/xfs/xfs_iget.c linux-2.4.25/fs/xfs/xfs_iget.c
@@ -0,0 +1,1003 @@
+/*
+ * Copyright (c) 2000-2003 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 "xfs_macros.h"
+#include "xfs_types.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_dir.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_btree.h"
+#include "xfs_ialloc.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_quota.h"
+#include "xfs_utils.h"
+
+/*
+ * Initialize the inode hash table for the newly mounted file system.
+ *
+ * mp -- this is the mount point structure for the file system being
+ *       initialized
+ */
+void
+xfs_ihash_init(xfs_mount_t *mp)
+{
+	int	i;
+
+	mp->m_ihsize = XFS_BUCKETS(mp);
+	mp->m_ihash = (xfs_ihash_t *)kmem_zalloc(mp->m_ihsize
+				      * sizeof(xfs_ihash_t), KM_SLEEP);
+	ASSERT(mp->m_ihash != NULL);
+	for (i = 0; i < mp->m_ihsize; i++) {
+		rwlock_init(&(mp->m_ihash[i].ih_lock));
+	}
+}
+
+/*
+ * Free up structures allocated by xfs_ihash_init, at unmount time.
+ */
+void
+xfs_ihash_free(xfs_mount_t *mp)
+{
+	kmem_free(mp->m_ihash, mp->m_ihsize*sizeof(xfs_ihash_t));
+	mp->m_ihash = NULL;
+}
+
+/*
+ * Initialize the inode cluster hash table for the newly mounted file system.
+ *
+ * mp -- this is the mount point structure for the file system being
+ *       initialized
+ */
+void
+xfs_chash_init(xfs_mount_t *mp)
+{
+	int	i;
+
+	/*
+	 * m_chash size is based on m_ihash
+	 * with a minimum of 37 entries
+	 */
+	mp->m_chsize = (XFS_BUCKETS(mp)) /
+			 (XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog);
+	if (mp->m_chsize < 37) {
+		mp->m_chsize = 37;
+	}
+	mp->m_chash = (xfs_chash_t *)kmem_zalloc(mp->m_chsize
+						 * sizeof(xfs_chash_t),
+						 KM_SLEEP);
+	ASSERT(mp->m_chash != NULL);
+
+	for (i = 0; i < mp->m_chsize; i++) {
+		spinlock_init(&mp->m_chash[i].ch_lock,"xfshash");
+	}
+}
+
+/*
+ * Free up structures allocated by xfs_chash_init, at unmount time.
+ */
+void
+xfs_chash_free(xfs_mount_t *mp)
+{
+	int	i;
+
+	for (i = 0; i < mp->m_chsize; i++) {
+		spinlock_destroy(&mp->m_chash[i].ch_lock);
+	}
+
+	kmem_free(mp->m_chash, mp->m_chsize*sizeof(xfs_chash_t));
+	mp->m_chash = NULL;
+}
+
+/*
+ * Look up an inode by number in the given file system.
+ * The inode is looked up in the hash table for the file system
+ * represented by the mount point parameter mp.  Each bucket of
+ * the hash table is guarded by an individual semaphore.
+ *
+ * If the inode is found in the hash table, its corresponding vnode
+ * is obtained with a call to vn_get().  This call takes care of
+ * coordination with the reclamation of the inode and vnode.  Note
+ * that the vmap structure is filled in while holding the hash lock.
+ * This gives us the state of the inode/vnode when we found it and
+ * is used for coordination in vn_get().
+ *
+ * If it is not in core, read it in from the file system's device and
+ * add the inode into the hash table.
+ *
+ * The inode is locked according to the value of the lock_flags parameter.
+ * This flag parameter indicates how and if the inode's IO lock and inode lock
+ * should be taken.
+ *
+ * mp -- the mount point structure for the current file system.  It points
+ *       to the inode hash table.
+ * tp -- a pointer to the current transaction if there is one.  This is
+ *       simply passed through to the xfs_iread() call.
+ * ino -- the number of the inode desired.  This is the unique identifier
+ *        within the file system for the inode being requested.
+ * lock_flags -- flags indicating how to lock the inode.  See the comment
+ *		 for xfs_ilock() for a list of valid values.
+ * bno -- the block number starting the buffer containing the inode,
+ *	  if known (as by bulkstat), else 0.
+ */
+STATIC int
+xfs_iget_core(
+	vnode_t		*vp,
+	xfs_mount_t	*mp,
+	xfs_trans_t	*tp,
+	xfs_ino_t	ino,
+	uint		lock_flags,
+	xfs_inode_t	**ipp,
+	xfs_daddr_t	bno)
+{
+	xfs_ihash_t	*ih;
+	xfs_inode_t	*ip;
+	xfs_inode_t	*iq;
+	vnode_t		*inode_vp;
+	ulong		version;
+	int		error;
+	/* REFERENCED */
+	int		newnode;
+	xfs_chash_t	*ch;
+	xfs_chashlist_t	*chl, *chlnew;
+	SPLDECL(s);
+
+
+	ih = XFS_IHASH(mp, ino);
+
+again:
+	read_lock(&ih->ih_lock);
+
+	for (ip = ih->ih_next; ip != NULL; ip = ip->i_next) {
+		if (ip->i_ino == ino) {
+
+			inode_vp = XFS_ITOV_NULL(ip);
+
+			if (inode_vp == NULL) {
+				/* If IRECLAIM is set this inode is
+				 * on its way out of the system,
+				 * we need to pause and try again.
+				 */
+				if (ip->i_flags & XFS_IRECLAIM) {
+					read_unlock(&ih->ih_lock);
+					delay(1);
+					XFS_STATS_INC(xs_ig_frecycle);
+
+					goto again;
+				}
+
+				vn_trace_exit(vp, "xfs_iget.alloc",
+					(inst_t *)__return_address);
+
+				XFS_STATS_INC(xs_ig_found);
+
+				ip->i_flags &= ~XFS_IRECLAIMABLE;
+				read_unlock(&ih->ih_lock);
+
+				XFS_MOUNT_ILOCK(mp);
+				list_del_init(&ip->i_reclaim);
+				XFS_MOUNT_IUNLOCK(mp);
+
+				goto finish_inode;
+
+			} else if (vp != inode_vp) {
+				struct inode *inode = LINVFS_GET_IP(inode_vp);
+
+				/* The inode is being torn down, pause and
+				 * try again.
+				 */
+				if (inode->i_state & (I_FREEING | I_CLEAR)) {
+					read_unlock(&ih->ih_lock);
+					delay(1);
+					XFS_STATS_INC(xs_ig_frecycle);
+
+					goto again;
+				}
+/* Chances are the other vnode (the one in the inode) is being torn
+ * down right now, and we landed on top of it. Question is, what do
+ * we do? Unhook the old inode and hook up the new one?
+ */
+				cmn_err(CE_PANIC,
+			"xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p",
+						inode_vp, vp);
+			}
+
+			read_unlock(&ih->ih_lock);
+
+			XFS_STATS_INC(xs_ig_found);
+
+finish_inode:
+			if (lock_flags != 0) {
+				xfs_ilock(ip, lock_flags);
+			}
+
+			newnode = (ip->i_d.di_mode == 0);
+			if (newnode) {
+				xfs_iocore_inode_reinit(ip);
+			}
+			ip->i_flags &= ~XFS_ISTALE;
+
+			vn_trace_exit(vp, "xfs_iget.found",
+						(inst_t *)__return_address);
+			goto return_ip;
+		}
+	}
+
+	/*
+	 * Inode cache miss: save the hash chain version stamp and unlock
+	 * the chain, so we don't deadlock in vn_alloc.
+	 */
+	XFS_STATS_INC(xs_ig_missed);
+
+	version = ih->ih_version;
+
+	read_unlock(&ih->ih_lock);
+
+	/*
+	 * Read the disk inode attributes into a new inode structure and get
+	 * a new vnode for it. This should also initialize i_ino and i_mount.
+	 */
+	error = xfs_iread(mp, tp, ino, &ip, bno);
+	if (error) {
+		return error;
+	}
+
+	vn_trace_exit(vp, "xfs_iget.alloc", (inst_t *)__return_address);
+
+	xfs_inode_lock_init(ip, vp);
+	xfs_iocore_inode_init(ip);
+
+	if (lock_flags != 0) {
+		xfs_ilock(ip, lock_flags);
+	}
+
+	/*
+	 * Put ip on its hash chain, unless someone else hashed a duplicate
+	 * after we released the hash lock.
+	 */
+	write_lock(&ih->ih_lock);
+
+	if (ih->ih_version != version) {
+		for (iq = ih->ih_next; iq != NULL; iq = iq->i_next) {
+			if (iq->i_ino == ino) {
+				write_unlock(&ih->ih_lock);
+				xfs_idestroy(ip);
+
+				XFS_STATS_INC(xs_ig_dup);
+				goto again;
+			}
+		}
+	}
+
+	/*
+	 * These values _must_ be set before releasing ihlock!
+	 */
+	ip->i_hash = ih;
+	if ((iq = ih->ih_next)) {
+		iq->i_prevp = &ip->i_next;
+	}
+	ip->i_next = iq;
+	ip->i_prevp = &ih->ih_next;
+	ih->ih_next = ip;
+	ip->i_udquot = ip->i_gdquot = NULL;
+	ih->ih_version++;
+
+	write_unlock(&ih->ih_lock);
+
+	/*
+	 * put ip on its cluster's hash chain
+	 */
+	ASSERT(ip->i_chash == NULL && ip->i_cprev == NULL &&
+	       ip->i_cnext == NULL);
+
+	chlnew = NULL;
+	ch = XFS_CHASH(mp, ip->i_blkno);
+ chlredo:
+	s = mutex_spinlock(&ch->ch_lock);
+	for (chl = ch->ch_list; chl != NULL; chl = chl->chl_next) {
+		if (chl->chl_blkno == ip->i_blkno) {
+
+			/* insert this inode into the doubly-linked list
+			 * where chl points */
+			if ((iq = chl->chl_ip)) {
+				ip->i_cprev = iq->i_cprev;
+				iq->i_cprev->i_cnext = ip;
+				iq->i_cprev = ip;
+				ip->i_cnext = iq;
+			} else {
+				ip->i_cnext = ip;
+				ip->i_cprev = ip;
+			}
+			chl->chl_ip = ip;
+			ip->i_chash = chl;
+			break;
+		}
+	}
+
+	/* no hash list found for this block; add a new hash list */
+	if (chl == NULL)  {
+		if (chlnew == NULL) {
+			mutex_spinunlock(&ch->ch_lock, s);
+			ASSERT(xfs_chashlist_zone != NULL);
+			chlnew = (xfs_chashlist_t *)
+					kmem_zone_alloc(xfs_chashlist_zone,
+						KM_SLEEP);
+			ASSERT(chlnew != NULL);
+			goto chlredo;
+		} else {
+			ip->i_cnext = ip;
+			ip->i_cprev = ip;
+			ip->i_chash = chlnew;
+			chlnew->chl_ip = ip;
+			chlnew->chl_blkno = ip->i_blkno;
+			chlnew->chl_next = ch->ch_list;
+			ch->ch_list = chlnew;
+			chlnew = NULL;
+		}
+	} else {
+		if (chlnew != NULL) {
+			kmem_zone_free(xfs_chashlist_zone, chlnew);
+		}
+	}
+
+	mutex_spinunlock(&ch->ch_lock, s);
+
+
+	/*
+	 * Link ip to its mount and thread it on the mount's inode list.
+	 */
+	XFS_MOUNT_ILOCK(mp);
+	if ((iq = mp->m_inodes)) {
+		ASSERT(iq->i_mprev->i_mnext == iq);
+		ip->i_mprev = iq->i_mprev;
+		iq->i_mprev->i_mnext = ip;
+		iq->i_mprev = ip;
+		ip->i_mnext = iq;
+	} else {
+		ip->i_mnext = ip;
+		ip->i_mprev = ip;
+	}
+	mp->m_inodes = ip;
+
+	XFS_MOUNT_IUNLOCK(mp);
+
+	newnode = 1;
+
+ return_ip:
+	ASSERT(ip->i_df.if_ext_max ==
+	       XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));
+
+	ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
+	       ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
+
+	*ipp = ip;
+
+	/*
+	 * If we have a real type for an on-disk inode, we can set ops(&unlock)
+	 * now.	 If it's a new inode being created, xfs_ialloc will handle it.
+	 */
+	VFS_INIT_VNODE(XFS_MTOVFS(mp), vp, XFS_ITOBHV(ip), 1);
+
+	return 0;
+}
+
+
+/*
+ * The 'normal' internal xfs_iget, if needed it will
+ * 'allocate', or 'get', the vnode.
+ */
+int
+xfs_iget(
+	xfs_mount_t	*mp,
+	xfs_trans_t	*tp,
+	xfs_ino_t	ino,
+	uint		lock_flags,
+	xfs_inode_t	**ipp,
+	xfs_daddr_t	bno)
+{
+	struct inode	*inode;
+	vnode_t		*vp = NULL;
+	int		error;
+
+retry:
+	XFS_STATS_INC(xs_ig_attempts);
+
+	if ((inode = VFS_GET_INODE(XFS_MTOVFS(mp), ino, 0))) {
+		bhv_desc_t	*bdp;
+		xfs_inode_t	*ip;
+		int		newnode;
+
+		vp = LINVFS_GET_VP(inode);
+		if (inode->i_state & I_NEW) {
+inode_allocate:
+			vn_initialize(inode);
+			error = xfs_iget_core(vp, mp, tp, ino,
+						lock_flags, ipp, bno);
+			if (error) {
+				remove_inode_hash(inode);
+				make_bad_inode(inode);
+				if (inode->i_state & I_NEW)
+					unlock_new_inode(inode);
+				iput(inode);
+			}
+		} else {
+			/* These are true if the inode is in inactive or
+			 * reclaim. The linux inode is about to go away,
+			 * wait for that path to finish, and try again.
+			 */
+			if (vp->v_flag & (VINACT | VRECLM)) {
+				vn_wait(vp);
+				iput(inode);
+				goto retry;
+			}
+
+			if (is_bad_inode(inode)) {
+				iput(inode);
+				return EIO;
+			}
+
+			bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
+			if (bdp == NULL) {
+				XFS_STATS_INC(xs_ig_dup);
+				goto inode_allocate;
+			}
+			ip = XFS_BHVTOI(bdp);
+			if (lock_flags != 0)
+				xfs_ilock(ip, lock_flags);
+			newnode = (ip->i_d.di_mode == 0);
+			if (newnode)
+				xfs_iocore_inode_reinit(ip);
+			XFS_STATS_INC(xs_ig_found);
+			*ipp = ip;
+			error = 0;
+		}
+	} else
+		error = ENOMEM;	/* If we got no inode we are out of memory */
+
+	return error;
+}
+
+/*
+ * Do the setup for the various locks within the incore inode.
+ */
+void
+xfs_inode_lock_init(
+	xfs_inode_t	*ip,
+	vnode_t		*vp)
+{
+	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
+		     "xfsino", (long)vp->v_number);
+	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", vp->v_number);
+	init_waitqueue_head(&ip->i_ipin_wait);
+	atomic_set(&ip->i_pincount, 0);
+	init_sema(&ip->i_flock, 1, "xfsfino", vp->v_number);
+}
+
+/*
+ * Look for the inode corresponding to the given ino in the hash table.
+ * If it is there and its i_transp pointer matches tp, return it.
+ * Otherwise, return NULL.
+ */
+xfs_inode_t *
+xfs_inode_incore(xfs_mount_t	*mp,
+		 xfs_ino_t	ino,
+		 xfs_trans_t	*tp)
+{
+	xfs_ihash_t	*ih;
+	xfs_inode_t	*ip;
+
+	ih = XFS_IHASH(mp, ino);
+	read_lock(&ih->ih_lock);
+	for (ip = ih->ih_next; ip != NULL; ip = ip->i_next) {
+		if (ip->i_ino == ino) {
+			/*
+			 * If we find it and tp matches, return it.
+			 * Otherwise break from the loop and return
+			 * NULL.
+			 */
+			if (ip->i_transp == tp) {
+				read_unlock(&ih->ih_lock);
+				return (ip);
+			}
+			break;
+		}
+	}
+	read_unlock(&ih->ih_lock);
+	return (NULL);
+}
+
+/*
+ * Decrement reference count of an inode structure and unlock it.
+ *
+ * ip -- the inode being released
+ * lock_flags -- this parameter indicates the inode's locks to be
+ *       to be released.  See the comment on xfs_iunlock() for a list
+ *	 of valid values.
+ */
+void
+xfs_iput(xfs_inode_t	*ip,
+	 uint		lock_flags)
+{
+	vnode_t	*vp = XFS_ITOV(ip);
+
+	vn_trace_entry(vp, "xfs_iput", (inst_t *)__return_address);
+
+	xfs_iunlock(ip, lock_flags);
+
+	VN_RELE(vp);
+}
+
+/*
+ * Special iput for brand-new inodes that are still locked
+ */
+void
+xfs_iput_new(xfs_inode_t	*ip,
+	     uint		lock_flags)
+{
+	vnode_t		*vp = XFS_ITOV(ip);
+	struct inode	*inode = LINVFS_GET_IP(vp);
+
+	vn_trace_entry(vp, "xfs_iput_new", (inst_t *)__return_address);
+
+	/* We shouldn't get here without this being true, but just in case */
+	if (inode->i_state & I_NEW) {
+		remove_inode_hash(inode);
+		make_bad_inode(inode);
+		unlock_new_inode(inode);
+	}
+	if (lock_flags)
+		xfs_iunlock(ip, lock_flags);
+	VN_RELE(vp);
+}
+
+
+/*
+ * This routine embodies the part of the reclaim code that pulls
+ * the inode from the inode hash table and the mount structure's
+ * inode list.
+ * This should only be called from xfs_reclaim().
+ */
+void
+xfs_ireclaim(xfs_inode_t *ip)
+{
+	vnode_t		*vp;
+
+	/*
+	 * Remove from old hash list and mount list.
+	 */
+	XFS_STATS_INC(xs_ig_reclaims);
+
+	xfs_iextract(ip);
+
+	/*
+	 * Here we do a spurious inode lock in order to coordinate with
+	 * xfs_sync().  This is because xfs_sync() references the inodes
+	 * in the mount list without taking references on the corresponding
+	 * vnodes.  We make that OK here by ensuring that we wait until
+	 * the inode is unlocked in xfs_sync() before we go ahead and
+	 * free it.  We get both the regular lock and the io lock because
+	 * the xfs_sync() code may need to drop the regular one but will
+	 * still hold the io lock.
+	 */
+	xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+
+	/*
+	 * Release dquots (and their references) if any. An inode may escape
+	 * xfs_inactive and get here via vn_alloc->vn_reclaim path.
+	 */
+	XFS_QM_DQDETACH(ip->i_mount, ip);
+
+	/*
+	 * Pull our behavior descriptor from the vnode chain.
+	 */
+	vp = XFS_ITOV_NULL(ip);
+	if (vp) {
+		vn_bhv_remove(VN_BHV_HEAD(vp), XFS_ITOBHV(ip));
+	}
+
+	/*
+	 * Free all memory associated with the inode.
+	 */
+	xfs_idestroy(ip);
+}
+
+/*
+ * This routine removes an about-to-be-destroyed inode from
+ * all of the lists in which it is located with the exception
+ * of the behavior chain.
+ */
+void
+xfs_iextract(
+	xfs_inode_t	*ip)
+{
+	xfs_ihash_t	*ih;
+	xfs_inode_t	*iq;
+	xfs_mount_t	*mp;
+	xfs_chash_t	*ch;
+	xfs_chashlist_t *chl, *chm;
+	SPLDECL(s);
+
+	ih = ip->i_hash;
+	write_lock(&ih->ih_lock);
+	if ((iq = ip->i_next)) {
+		iq->i_prevp = ip->i_prevp;
+	}
+	*ip->i_prevp = iq;
+	write_unlock(&ih->ih_lock);
+
+	/*
+	 * Remove from cluster hash list
+	 *   1) delete the chashlist if this is the last inode on the chashlist
+	 *   2) unchain from list of inodes
+	 *   3) point chashlist->chl_ip to 'chl_next' if to this inode.
+	 */
+	mp = ip->i_mount;
+	ch = XFS_CHASH(mp, ip->i_blkno);
+	s = mutex_spinlock(&ch->ch_lock);
+
+	if (ip->i_cnext == ip) {
+		/* Last inode on chashlist */
+		ASSERT(ip->i_cnext == ip && ip->i_cprev == ip);
+		ASSERT(ip->i_chash != NULL);
+		chm=NULL;
+		for (chl = ch->ch_list; chl != NULL; chl = chl->chl_next) {
+			if (chl->chl_blkno == ip->i_blkno) {
+				if (chm == NULL) {
+					/* first item on the list */
+					ch->ch_list = chl->chl_next;
+				} else {
+					chm->chl_next = chl->chl_next;
+				}
+				kmem_zone_free(xfs_chashlist_zone, chl);
+				break;
+			} else {
+				ASSERT(chl->chl_ip != ip);
+				chm = chl;
+			}
+		}
+		ASSERT_ALWAYS(chl != NULL);
+       } else {
+		/* delete one inode from a non-empty list */
+		iq = ip->i_cnext;
+		iq->i_cprev = ip->i_cprev;
+		ip->i_cprev->i_cnext = iq;
+		if (ip->i_chash->chl_ip == ip) {
+			ip->i_chash->chl_ip = iq;
+		}
+		ip->i_chash = __return_address;
+		ip->i_cprev = __return_address;
+		ip->i_cnext = __return_address;
+	}
+	mutex_spinunlock(&ch->ch_lock, s);
+
+	/*
+	 * Remove from mount's inode list.
+	 */
+	XFS_MOUNT_ILOCK(mp);
+	ASSERT((ip->i_mnext != NULL) && (ip->i_mprev != NULL));
+	iq = ip->i_mnext;
+	iq->i_mprev = ip->i_mprev;
+	ip->i_mprev->i_mnext = iq;
+
+	/*
+	 * Fix up the head pointer if it points to the inode being deleted.
+	 */
+	if (mp->m_inodes == ip) {
+		if (ip == iq) {
+			mp->m_inodes = NULL;
+		} else {
+			mp->m_inodes = iq;
+		}
+	}
+
+	/* Deal with the deleted inodes list */
+	list_del_init(&ip->i_reclaim);
+
+	mp->m_ireclaims++;
+	XFS_MOUNT_IUNLOCK(mp);
+}
+
+/*
+ * This is a wrapper routine around the xfs_ilock() routine
+ * used to centralize some grungy code.  It is used in places
+ * that wish to lock the inode solely for reading the extents.
+ * The reason these places can't just call xfs_ilock(SHARED)
+ * is that the inode lock also guards to bringing in of the
+ * extents from disk for a file in b-tree format.  If the inode
+ * is in b-tree format, then we need to lock the inode exclusively
+ * until the extents are read in.  Locking it exclusively all
+ * the time would limit our parallelism unnecessarily, though.
+ * What we do instead is check to see if the extents have been
+ * read in yet, and only lock the inode exclusively if they
+ * have not.
+ *
+ * The function returns a value which should be given to the
+ * corresponding xfs_iunlock_map_shared().  This value is
+ * the mode in which the lock was actually taken.
+ */
+uint
+xfs_ilock_map_shared(
+	xfs_inode_t	*ip)
+{
+	uint	lock_mode;
+
+	if ((ip->i_d.di_format == XFS_DINODE_FMT_BTREE) &&
+	    ((ip->i_df.if_flags & XFS_IFEXTENTS) == 0)) {
+		lock_mode = XFS_ILOCK_EXCL;
+	} else {
+		lock_mode = XFS_ILOCK_SHARED;
+	}
+
+	xfs_ilock(ip, lock_mode);
+
+	return lock_mode;
+}
+
+/*
+ * This is simply the unlock routine to go with xfs_ilock_map_shared().
+ * All it does is call xfs_iunlock() with the given lock_mode.
+ */
+void
+xfs_iunlock_map_shared(
+	xfs_inode_t	*ip,
+	unsigned int	lock_mode)
+{
+	xfs_iunlock(ip, lock_mode);
+}
+
+/*
+ * The xfs inode contains 2 locks: a multi-reader lock called the
+ * i_iolock and a multi-reader lock called the i_lock.  This routine
+ * allows either or both of the locks to be obtained.
+ *
+ * The 2 locks should always be ordered so that the IO lock is
+ * obtained first in order to prevent deadlock.
+ *
+ * ip -- the inode being locked
+ * lock_flags -- this parameter indicates the inode's locks
+ *       to be locked.  It can be:
+ *		XFS_IOLOCK_SHARED,
+ *		XFS_IOLOCK_EXCL,
+ *		XFS_ILOCK_SHARED,
+ *		XFS_ILOCK_EXCL,
+ *		XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED,
+ *		XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL,
+ *		XFS_IOLOCK_EXCL | XFS_ILOCK_SHARED,
+ *		XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL
+ */
+void
+xfs_ilock(xfs_inode_t	*ip,
+	  uint		lock_flags)
+{
+	/*
+	 * You can't set both SHARED and EXCL for the same lock,
+	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
+	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
+	 */
+	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
+	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
+	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
+	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+	ASSERT((lock_flags & ~XFS_LOCK_MASK) == 0);
+
+	if (lock_flags & XFS_IOLOCK_EXCL) {
+		mrupdate(&ip->i_iolock);
+	} else if (lock_flags & XFS_IOLOCK_SHARED) {
+		mraccess(&ip->i_iolock);
+	}
+	if (lock_flags & XFS_ILOCK_EXCL) {
+		mrupdate(&ip->i_lock);
+	} else if (lock_flags & XFS_ILOCK_SHARED) {
+		mraccess(&ip->i_lock);
+	}
+	xfs_ilock_trace(ip, 1, lock_flags, (inst_t *)__return_address);
+}
+
+/*
+ * This is just like xfs_ilock(), except that the caller
+ * is guaranteed not to sleep.  It returns 1 if it gets
+ * the requested locks and 0 otherwise.  If the IO lock is
+ * obtained but the inode lock cannot be, then the IO lock
+ * is dropped before returning.
+ *
+ * ip -- the inode being locked
+ * lock_flags -- this parameter indicates the inode's locks to be
+ *       to be locked.  See the comment for xfs_ilock() for a list
+ *	 of valid values.
+ *
+ */
+int
+xfs_ilock_nowait(xfs_inode_t	*ip,
+		 uint		lock_flags)
+{
+	int	iolocked;
+	int	ilocked;
+
+	/*
+	 * You can't set both SHARED and EXCL for the same lock,
+	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
+	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
+	 */
+	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
+	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
+	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
+	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+	ASSERT((lock_flags & ~XFS_LOCK_MASK) == 0);
+
+	iolocked = 0;
+	if (lock_flags & XFS_IOLOCK_EXCL) {
+		iolocked = mrtryupdate(&ip->i_iolock);
+		if (!iolocked) {
+			return 0;
+		}
+	} else if (lock_flags & XFS_IOLOCK_SHARED) {
+		iolocked = mrtryaccess(&ip->i_iolock);
+		if (!iolocked) {
+			return 0;
+		}
+	}
+	if (lock_flags & XFS_ILOCK_EXCL) {
+		ilocked = mrtryupdate(&ip->i_lock);
+		if (!ilocked) {
+			if (iolocked) {
+				mrunlock(&ip->i_iolock);
+			}
+			return 0;
+		}
+	} else if (lock_flags & XFS_ILOCK_SHARED) {
+		ilocked = mrtryaccess(&ip->i_lock);
+		if (!ilocked) {
+			if (iolocked) {
+				mrunlock(&ip->i_iolock);
+			}
+			return 0;
+		}
+	}
+	xfs_ilock_trace(ip, 2, lock_flags, (inst_t *)__return_address);
+	return 1;
+}
+
+/*
+ * xfs_iunlock() is used to drop the inode locks acquired with
+ * xfs_ilock() and xfs_ilock_nowait().  The caller must pass
+ * in the flags given to xfs_ilock() or xfs_ilock_nowait() so
+ * that we know which locks to drop.
+ *
+ * ip -- the inode being unlocked
+ * lock_flags -- this parameter indicates the inode's locks to be
+ *       to be unlocked.  See the comment for xfs_ilock() for a list
+ *	 of valid values for this parameter.
+ *
+ */
+void
+xfs_iunlock(xfs_inode_t	*ip,
+	    uint	lock_flags)
+{
+	/*
+	 * You can't set both SHARED and EXCL for the same lock,
+	 * and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
+	 * and XFS_ILOCK_EXCL are valid values to set in lock_flags.
+	 */
+	ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
+	       (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
+	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
+	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_IUNLOCK_NONOTIFY)) == 0);
+	ASSERT(lock_flags != 0);
+
+	if (lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) {
+		ASSERT(!(lock_flags & XFS_IOLOCK_SHARED) ||
+		       (ismrlocked(&ip->i_iolock, MR_ACCESS)));
+		ASSERT(!(lock_flags & XFS_IOLOCK_EXCL) ||
+		       (ismrlocked(&ip->i_iolock, MR_UPDATE)));
+		mrunlock(&ip->i_iolock);
+	}
+
+	if (lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) {
+		ASSERT(!(lock_flags & XFS_ILOCK_SHARED) ||
+		       (ismrlocked(&ip->i_lock, MR_ACCESS)));
+		ASSERT(!(lock_flags & XFS_ILOCK_EXCL) ||
+		       (ismrlocked(&ip->i_lock, MR_UPDATE)));
+		mrunlock(&ip->i_lock);
+
+		/*
+		 * Let the AIL know that this item has been unlocked in case
+		 * it is in the AIL and anyone is waiting on it.  Don't do
+		 * this if the caller has asked us not to.
+		 */
+		if (!(lock_flags & XFS_IUNLOCK_NONOTIFY) &&
+		     ip->i_itemp != NULL) {
+			xfs_trans_unlocked_item(ip->i_mount,
+						(xfs_log_item_t*)(ip->i_itemp));
+		}
+	}
+	xfs_ilock_trace(ip, 3, lock_flags, (inst_t *)__return_address);
+}
+
+/*
+ * give up write locks.  the i/o lock cannot be held nested
+ * if it is being demoted.
+ */
+void
+xfs_ilock_demote(xfs_inode_t	*ip,
+		 uint		lock_flags)
+{
+	ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL));
+	ASSERT((lock_flags & ~(XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
+
+	if (lock_flags & XFS_ILOCK_EXCL) {
+		ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
+		mrdemote(&ip->i_lock);
+	}
+	if (lock_flags & XFS_IOLOCK_EXCL) {
+		ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
+		mrdemote(&ip->i_iolock);
+	}
+}
+
+/*
+ * The following three routines simply manage the i_flock
+ * semaphore embedded in the inode.  This semaphore synchronizes
+ * processes attempting to flush the in-core inode back to disk.
+ */
+void
+xfs_iflock(xfs_inode_t *ip)
+{
+	psema(&(ip->i_flock), PINOD|PLTWAIT);
+}
+
+int
+xfs_iflock_nowait(xfs_inode_t *ip)
+{
+	return (cpsema(&(ip->i_flock)));
+}
+
+void
+xfs_ifunlock(xfs_inode_t *ip)
+{
+	ASSERT(valusema(&(ip->i_flock)) <= 0);
+	vsema(&(ip->i_flock));
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)