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33 * @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
34 * $FreeBSD: src/sys/ufs/ufs/ufs_ihash.c,v 1.20 1999/08/28 00:52:29 peter Exp $
35 * $DragonFly: src/sys/vfs/ufs/ufs_ihash.c,v 1.8 2003/11/13 16:26:42 drhodus Exp $
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
42 #include <sys/vnode.h>
43 #include <sys/malloc.h>
48 #include "ufs_extern.h"
50 static MALLOC_DEFINE(M_UFSIHASH, "UFS ihash", "UFS Inode hash tables");
52 * Structures associated with inode cacheing.
54 static LIST_HEAD(ihashhead, inode) *ihashtbl;
55 static u_long ihash; /* size of hash table - 1 */
56 #define INOHASH(device, inum) (&ihashtbl[(minor(device) + (inum)) & ihash])
57 static struct lwkt_token ufs_ihash_token;
60 * Initialize inode hash table.
65 ihashtbl = hashinit(desiredvnodes, M_UFSIHASH, &ihash);
66 lwkt_inittoken(&ufs_ihash_token);
70 * Use the device/inum pair to find the incore inode, and return a pointer
71 * to it. If it is in core, return it, even if it is locked.
74 ufs_ihashlookup(dev, inum)
80 lwkt_gettoken(&ufs_ihash_token);
81 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next)
82 if (inum == ip->i_number && dev == ip->i_dev)
84 lwkt_reltoken(&ufs_ihash_token);
92 * Use the device/inum pair to find the incore inode, and return a pointer
93 * to it. If it is in core, but locked, wait for it.
95 * Any time we potentially block we must regenerate the token using
96 * lwkt_gentoken(), which at the same time checks the generation number
97 * indicating whether another entity stole the token while we were blocked.
98 * In the best case lwkt_gentoken(). The code below is probably overkill,
99 * but it is particularly important to check the generation number after
100 * acquiring the vnode lock to ensure that the inode association is still
104 ufs_ihashget(dev_t dev, ino_t inum)
106 struct thread *td = curthread; /* XXX */
111 gen = lwkt_gettoken(&ufs_ihash_token);
113 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) {
114 if (inum == ip->i_number && dev == ip->i_dev) {
117 lwkt_gettoken(&vp->v_interlock);
118 if (lwkt_gentoken(&ufs_ihash_token, &gen) != 0) {
119 lwkt_reltoken(&vp->v_interlock);
123 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, td)) {
125 lwkt_gentoken(&ufs_ihash_token, &gen);
128 if (lwkt_reltoken(&ufs_ihash_token) != gen) {
131 gen = lwkt_gettoken(&ufs_ihash_token);
137 lwkt_reltoken(&ufs_ihash_token);
142 * Insert the inode into the hash table, and return it locked.
145 ufs_ihashins(struct inode *ip)
147 struct thread *td = curthread; /* XXX */
148 struct ihashhead *ipp;
150 /* lock the inode, then put it on the appropriate hash list */
151 lockmgr(&ip->i_lock, LK_EXCLUSIVE, NULL, td);
153 lwkt_gettoken(&ufs_ihash_token);
154 ipp = INOHASH(ip->i_dev, ip->i_number);
155 LIST_INSERT_HEAD(ipp, ip, i_hash);
156 ip->i_flag |= IN_HASHED;
157 lwkt_reltoken(&ufs_ihash_token);
161 * Remove the inode from the hash table.
167 lwkt_gettoken(&ufs_ihash_token);
168 if (ip->i_flag & IN_HASHED) {
169 ip->i_flag &= ~IN_HASHED;
170 LIST_REMOVE(ip, i_hash);
172 ip->i_hash.le_next = NULL;
173 ip->i_hash.le_prev = NULL;
176 lwkt_reltoken(&ufs_ihash_token);