/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2022 Marshall Kirk McKusick <mckusick@mckusick.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _G_UNION_H_ #define _G_UNION_H_ #define G_UNION_CLASS_NAME "UNION" #define G_UNION_VERSION 1 #define G_UNION_SUFFIX ".union" /* * Special flag to instruct gunion to passthrough the underlying provider's * physical path */ #define G_UNION_PHYSPATH_PASSTHROUGH "\255" #ifdef _KERNEL #define G_UNION_DEBUG(lvl, ...) \ _GEOM_DEBUG("GEOM_UNION", g_union_debug, (lvl), NULL, __VA_ARGS__) #define G_UNION_LOGREQLVL(lvl, bp, ...) \ _GEOM_DEBUG("GEOM_UNION", g_union_debug, (lvl), (bp), __VA_ARGS__) #define G_UNION_LOGREQ(bp, ...) G_UNION_LOGREQLVL(3, (bp), __VA_ARGS__) TAILQ_HEAD(wiplist, g_union_wip); /* * State maintained by each instance of a UNION GEOM. */ struct g_union_softc { struct rwlock sc_rwlock; /* writemap lock */ uint64_t **sc_writemap_root; /* root of write map */ uint64_t *sc_leafused; /* 1 => leaf has allocation */ uint64_t sc_map_size; /* size of write map */ long sc_root_size; /* entries in root node */ long sc_leaf_size; /* entries in leaf node */ long sc_bits_per_leaf; /* bits per leaf node entry */ long sc_writemap_memory; /* memory used by writemap */ off_t sc_offset; /* starting offset in lower */ off_t sc_size; /* size of union geom */ off_t sc_sectorsize; /* sector size of geom */ struct g_consumer *sc_uppercp; /* upper-level provider */ struct g_consumer *sc_lowercp; /* lower-level provider */ struct wiplist sc_wiplist; /* I/O work-in-progress list */ long sc_flags; /* see flags below */ long sc_reads; /* number of reads done */ long sc_wrotebytes; /* number of bytes written */ long sc_writes; /* number of writes done */ long sc_readbytes; /* number of bytes read */ long sc_deletes; /* number of deletes done */ long sc_getattrs; /* number of getattrs done */ long sc_flushes; /* number of flushes done */ long sc_cmd0s; /* number of cmd0's done */ long sc_cmd1s; /* number of cmd1's done */ long sc_cmd2s; /* number of cmd2's done */ long sc_speedups; /* number of speedups done */ long sc_readcurrentread; /* reads current with read */ long sc_readblockwrite; /* writes blocked by read */ long sc_writeblockread; /* reads blocked by write */ long sc_writeblockwrite; /* writes blocked by write */ }; /* * Structure to track work-in-progress I/O operations. * * Used to prevent overlapping I/O operations from running concurrently. * Created for each I/O operation. * * In usual case of no overlap it is linked to sc_wiplist and started. * If found to overlap an I/O on sc_wiplist, it is not started and is * linked to wip_waiting list of the I/O that it overlaps. When an I/O * completes, it restarts all the I/O operations on its wip_waiting list. */ struct g_union_wip { struct wiplist wip_waiting; /* list of I/Os waiting on me */ TAILQ_ENTRY(g_union_wip) wip_next; /* pending or active I/O list */ struct bio *wip_bp; /* bio for this I/O */ struct g_union_softc *wip_sc; /* g_union's softc */ off_t wip_start; /* starting offset of I/O */ off_t wip_end; /* ending offset of I/O */ long wip_numios; /* BIO_READs in progress */ long wip_error; /* merged I/O errors */ }; /* * UNION flags */ #define DOING_COMMIT 0x00000001 /* a commit command is in progress */ #define DOING_COMMIT_BITNUM 0 /* a commit command is in progress */ #define BITS_PER_ENTRY (sizeof(uint64_t) * NBBY) #define G_RLOCK(sc) rw_rlock(&(sc)->sc_rwlock) #define G_RUNLOCK(sc) rw_runlock(&(sc)->sc_rwlock) #define G_WLOCK(sc) rw_wlock(&(sc)->sc_rwlock) #define G_WUNLOCK(sc) rw_wunlock(&(sc)->sc_rwlock) #define G_WLOCKOWNED(sc) rw_assert(&(sc)->sc_rwlock, RA_WLOCKED) /* * The writelock is held while a commit operation is in progress. * While held union device may not be used or in use. * Returns == 0 if lock was successfully obtained. */ static inline int g_union_get_writelock(struct g_union_softc *sc) { return (atomic_testandset_long(&sc->sc_flags, DOING_COMMIT_BITNUM)); } static inline void g_union_rel_writelock(struct g_union_softc *sc) { long ret __diagused; ret = atomic_testandclear_long(&sc->sc_flags, DOING_COMMIT_BITNUM); KASSERT(ret != 0, ("UNION GEOM releasing unheld lock")); } #endif /* _KERNEL */ #endif /* _G_UNION_H_ */
