ufs/ufs/ufs_dirhash.c

59 #include <ufs/ufs/dirhash.h>
78     0, "maximum allowed dirhash memory usage");
81     0, "current dirhash memory usage");
94 static int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen);
95 static void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff);
96 static void ufsdirhash_delslot(struct dirhash *dh, int slot);
97 static int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen,
114 static TAILQ_HEAD(, dirhash) ufsdirhash_list;
122  * The relationship between inode and dirhash is protected either by an
124  * may be used.  The dirhash_mtx is acquired after the dirhash lock.  To
125  * handle teardown races, code wishing to lock the dirhash for an inode
127  * dirhash while holding the vnode interlock.  They can drop it once they
128  * have obtained the dirhash lock and verified that the dirhash wasn't
129  * recycled while they waited for the dirhash lock.
131  * ufsdirhash_build() acquires a shared lock on the dirhash when it is
135  * free a dirhash structure that was recycled by ufsdirhash_recycle().
137  * The dirhash lock may be held across io operations.
140  * and the "dirhash" lock.  However, this specific reversal will not
142  * buffer followed by the dirhash while a second thread locked a
143  * buffer while holding the dirhash lock.  The second order can happen
147  * a thread to be doing a "bufwait" -> "dirhash" order, it has to hold
149  * any other threads from doing a "dirhash" -> "bufwait" order.
153 ufsdirhash_hold(struct dirhash *dh)
160 ufsdirhash_drop(struct dirhash *dh)
170  * Release the lock on a dirhash.
173 ufsdirhash_release(struct dirhash *dh)
186 static struct dirhash *
189 	struct dirhash *ndh;
190 	struct dirhash *dh;
198 		/* Racy check for i_dirhash to prefetch a dirhash structure. */
210 			 * the one for this dirhash we are creating
214 			sx_init_flags(&ndh->dh_lock, "dirhash", SX_DUPOK);
272 static struct dirhash *
275 	struct dirhash *dh;
298 	struct dirhash *dh;
303 		/* Grab a reference on this inode's dirhash if it has one. */
313 		/* Exclusively lock the dirhash. */
316 		/* If this dirhash still belongs to this inode, then free it. */
326 		 * This inode's dirhash has changed while we were
327 		 * waiting for the dirhash lock, so try again.
342 	struct dirhash *dh;
357 	/* Check if we can/should use dirhash. */
480 	struct dirhash *dh;
508 	 * own reference on the dirhash structure.  They will drop
549 	struct dirhash *dh, *dh_next;
559 	    ("ufsdirhash_lookup: Invalid dirhash %p\n", dh));
562 	 * Move this dirhash towards the end of the list if it has a
575 			KASSERT(dh->dh_onlist, ("dirhash: not on list"));
703 	struct dirhash *dh;
710 	    ("ufsdirhash_findfree: Invalid dirhash %p\n", dh));
778 	struct dirhash *dh;
784 	    ("ufsdirhash_enduseful: Invalid dirhash %p\n", dh));
804 	struct dirhash *dh;
845 	struct dirhash *dh;
872 	struct dirhash *dh;
888  * Inform dirhash that the directory has grown by one block that
894 	struct dirhash *dh;
918  * Inform dirhash that the directory is being truncated.
923 	struct dirhash *dh;
961  * Debugging function to check that the dirhash information about
972 	struct dirhash *dh;
1027  * Hash the specified filename into a dirhash slot.
1030 ufsdirhash_hash(struct dirhash *dh, char *name, int namelen)
1036 	 * invariant over the dirhash's lifetime. Otherwise names
1054 ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff)
1061 	     ("dirhash bad offset"));
1090 ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset)
1097 	KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full"));
1114 ufsdirhash_delslot(struct dirhash *dh, int slot)
1171  * Delete the given dirhash and reclaim its memory. Assumes that
1176 ufsdirhash_destroy(struct dirhash *dh)
1182 	KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list"));
1195 	/* Unlock dirhash and free the detached memory. */
1215 	struct dirhash *dh;
1249 	struct dirhash *dh, *dh_temp;
1252 	 * Will free a *minimum* of 10% of the dirhash, but possibly much
1264 	 * seconds. If we can't get a lock on the dirhash, it will be skipped.
1271 		/* Unlock if we didn't delete the dirhash */
1278 	 * of the dirhash list. The ones closest to the head should be the
1302 	mtx_init(&ufsdirhash_mtx, "dirhash list", NULL, MTX_DEF);