mirror of https://github.com/openzfs/zfs.git
118 lines
3.3 KiB
C
118 lines
3.3 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#ifndef _SYS_FS_ZFS_RLOCK_H
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#define _SYS_FS_ZFS_RLOCK_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <sys/list.h>
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#include <sys/avl.h>
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#ifdef _KERNEL
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#include <sys/condvar.h>
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#else
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#include <sys/zfs_context.h>
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#endif
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typedef enum {
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RL_READER,
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RL_WRITER,
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RL_APPEND
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} rl_type_t;
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typedef struct zfs_rlock {
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kmutex_t zr_mutex; /* protects changes to zr_avl */
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avl_tree_t zr_avl; /* avl tree of range locks */
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uint64_t *zr_size; /* points to znode->z_size */
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uint_t *zr_blksz; /* points to znode->z_blksz */
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uint64_t *zr_max_blksz; /* points to zfsvfs->z_max_blksz */
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} zfs_rlock_t;
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typedef struct rl {
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zfs_rlock_t *r_zrl;
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avl_node_t r_node; /* avl node link */
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uint64_t r_off; /* file range offset */
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uint64_t r_len; /* file range length */
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uint_t r_cnt; /* range reference count in tree */
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rl_type_t r_type; /* range type */
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kcondvar_t r_wr_cv; /* cv for waiting writers */
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kcondvar_t r_rd_cv; /* cv for waiting readers */
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uint8_t r_proxy; /* acting for original range */
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uint8_t r_write_wanted; /* writer wants to lock this range */
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uint8_t r_read_wanted; /* reader wants to lock this range */
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list_node_t rl_node; /* used for deferred release */
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} rl_t;
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/*
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* Lock a range (offset, length) as either shared (RL_READER)
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* or exclusive (RL_WRITER or RL_APPEND). RL_APPEND is a special type that
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* is converted to RL_WRITER that specified to lock from the start of the
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* end of file. Returns the range lock structure.
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*/
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rl_t *zfs_range_lock(zfs_rlock_t *zrl, uint64_t off, uint64_t len,
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rl_type_t type);
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/* Unlock range and destroy range lock structure. */
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void zfs_range_unlock(rl_t *rl);
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/*
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* Reduce range locked as RW_WRITER from whole file to specified range.
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* Asserts the whole file was previously locked.
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*/
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void zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len);
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/*
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* AVL comparison function used to order range locks
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* Locks are ordered on the start offset of the range.
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*/
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int zfs_range_compare(const void *arg1, const void *arg2);
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static inline void
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zfs_rlock_init(zfs_rlock_t *zrl)
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{
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mutex_init(&zrl->zr_mutex, NULL, MUTEX_DEFAULT, NULL);
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avl_create(&zrl->zr_avl, zfs_range_compare,
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sizeof (rl_t), offsetof(rl_t, r_node));
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zrl->zr_size = NULL;
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zrl->zr_blksz = NULL;
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zrl->zr_max_blksz = NULL;
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}
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static inline void
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zfs_rlock_destroy(zfs_rlock_t *zrl)
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{
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avl_destroy(&zrl->zr_avl);
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mutex_destroy(&zrl->zr_mutex);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SYS_FS_ZFS_RLOCK_H */
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