/* * Copyright (c) 1994,1997 John S. Dyson * All rights reserved. * * 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 immediately at the beginning of the file, without modification, * this list of conditions, and the following disclaimer. * 2. Absolutely no warranty of function or purpose is made by the author * John S. Dyson. * * $Id: vfs_bio.c,v 1.177 1998/09/25 17:34:49 peter Exp $ */ /* * this file contains a new buffer I/O scheme implementing a coherent * VM object and buffer cache scheme. Pains have been taken to make * sure that the performance degradation associated with schemes such * as this is not realized. * * Author: John S. Dyson * Significant help during the development and debugging phases * had been provided by David Greenman, also of the FreeBSD core team. */ #define VMIO #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_BIOBUF, "BIO buffer", "BIO buffer"); struct bio_ops bioops; /* I/O operation notification */ #if 0 /* replaced bu sched_sync */ static void vfs_update __P((void)); static struct proc *updateproc; static struct kproc_desc up_kp = { "update", vfs_update, &updateproc }; SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp) #endif struct buf *buf; /* buffer header pool */ struct swqueue bswlist; static int count_lock_queue __P((void)); static void vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to); static void vm_hold_load_pages(struct buf * bp, vm_offset_t from, vm_offset_t to); static void vfs_buf_set_valid(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, vm_offset_t size, vm_page_t m); static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, int pageno, vm_page_t m); static void vfs_clean_pages(struct buf * bp); static void vfs_setdirty(struct buf *bp); static void vfs_vmio_release(struct buf *bp); static void flushdirtybuffers(int slpflag, int slptimeo); int needsbuffer; /* * Internal update daemon, process 3 * The variable vfs_update_wakeup allows for internal syncs. */ int vfs_update_wakeup; /* * buffers base kva */ /* * bogus page -- for I/O to/from partially complete buffers * this is a temporary solution to the problem, but it is not * really that bad. it would be better to split the buffer * for input in the case of buffers partially already in memory, * but the code is intricate enough already. */ vm_page_t bogus_page; static vm_offset_t bogus_offset; static int bufspace, maxbufspace, vmiospace, maxvmiobufspace, bufmallocspace, maxbufmallocspace; int numdirtybuffers; static int lodirtybuffers, hidirtybuffers; static int numfreebuffers, lofreebuffers, hifreebuffers; static int kvafreespace; SYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, &numdirtybuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, &lodirtybuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, &hidirtybuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, &numfreebuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, &lofreebuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, &hifreebuffers, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RW, &maxbufspace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, &bufspace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, maxvmiobufspace, CTLFLAG_RW, &maxvmiobufspace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, vmiospace, CTLFLAG_RD, &vmiospace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, &maxbufmallocspace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, &bufmallocspace, 0, ""); SYSCTL_INT(_vfs, OID_AUTO, kvafreespace, CTLFLAG_RD, &kvafreespace, 0, ""); static LIST_HEAD(bufhashhdr, buf) bufhashtbl[BUFHSZ], invalhash; struct bqueues bufqueues[BUFFER_QUEUES] = {0}; extern int vm_swap_size; #define BUF_MAXUSE 24 #define VFS_BIO_NEED_ANY 1 #define VFS_BIO_NEED_LOWLIMIT 2 #define VFS_BIO_NEED_FREE 4 /* * Initialize buffer headers and related structures. */ void bufinit() { struct buf *bp; int i; TAILQ_INIT(&bswlist); LIST_INIT(&invalhash); /* first, make a null hash table */ for (i = 0; i < BUFHSZ; i++) LIST_INIT(&bufhashtbl[i]); /* next, make a null set of free lists */ for (i = 0; i < BUFFER_QUEUES; i++) TAILQ_INIT(&bufqueues[i]); /* finally, initialize each buffer header and stick on empty q */ for (i = 0; i < nbuf; i++) { bp = &buf[i]; bzero(bp, sizeof *bp); bp->b_flags = B_INVAL; /* we're just an empty header */ bp->b_dev = NODEV; bp->b_rcred = NOCRED; bp->b_wcred = NOCRED; bp->b_qindex = QUEUE_EMPTY; bp->b_vnbufs.le_next = NOLIST; LIST_INIT(&bp->b_dep); TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); LIST_INSERT_HEAD(&invalhash, bp, b_hash); } /* * maxbufspace is currently calculated to support all filesystem blocks * to be 8K. If you happen to use a 16K filesystem, the size of the buffer * cache is still the same as it would be for 8K filesystems. This * keeps the size of the buffer cache "in check" for big block filesystems. */ maxbufspace = (nbuf + 8) * DFLTBSIZE; /* * reserve 1/3 of the buffers for metadata (VDIR) which might not be VMIO'ed */ maxvmiobufspace = 2 * maxbufspace / 3; /* * Limit the amount of malloc memory since it is wired permanently into * the kernel space. Even though this is accounted for in the buffer * allocation, we don't want the malloced region to grow uncontrolled. * The malloc scheme improves memory utilization significantly on average * (small) directories. */ maxbufmallocspace = maxbufspace / 20; /* * Remove the probability of deadlock conditions by limiting the * number of dirty buffers. */ hidirtybuffers = nbuf / 8 + 20; lodirtybuffers = nbuf / 16 + 10; numdirtybuffers = 0; lofreebuffers = nbuf / 18 + 5; hifreebuffers = 2 * lofreebuffers; numfreebuffers = nbuf; kvafreespace = 0; bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE); bogus_page = vm_page_alloc(kernel_object, ((bogus_offset - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), VM_ALLOC_NORMAL); } /* * Free the kva allocation for a buffer * Must be called only at splbio or higher, * as this is the only locking for buffer_map. */ static void bfreekva(struct buf * bp) { if (bp->b_kvasize == 0) return; vm_map_delete(buffer_map, (vm_offset_t) bp->b_kvabase, (vm_offset_t) bp->b_kvabase + bp->b_kvasize); bp->b_kvasize = 0; } /* * remove the buffer from the appropriate free list */ void bremfree(struct buf * bp) { int s = splbio(); if (bp->b_qindex != QUEUE_NONE) { if (bp->b_qindex == QUEUE_EMPTY) { kvafreespace -= bp->b_kvasize; } TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); bp->b_qindex = QUEUE_NONE; } else { #if !defined(MAX_PERF) panic("bremfree: removing a buffer when not on a queue"); #endif } if ((bp->b_flags & B_INVAL) || (bp->b_flags & (B_DELWRI|B_LOCKED)) == 0) --numfreebuffers; splx(s); } /* * Get a buffer with the specified data. Look in the cache first. */ int bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred, struct buf ** bpp) { struct buf *bp; bp = getblk(vp, blkno, size, 0, 0); *bpp = bp; /* if not found in cache, do some I/O */ if ((bp->b_flags & B_CACHE) == 0) { if (curproc != NULL) curproc->p_stats->p_ru.ru_inblock++; bp->b_flags |= B_READ; bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); if (bp->b_rcred == NOCRED) { if (cred != NOCRED) crhold(cred); bp->b_rcred = cred; } vfs_busy_pages(bp, 0); VOP_STRATEGY(vp, bp); return (biowait(bp)); } return (0); } /* * Operates like bread, but also starts asynchronous I/O on * read-ahead blocks. */ int breadn(struct vnode * vp, daddr_t blkno, int size, daddr_t * rablkno, int *rabsize, int cnt, struct ucred * cred, struct buf ** bpp) { struct buf *bp, *rabp; int i; int rv = 0, readwait = 0; *bpp = bp = getblk(vp, blkno, size, 0, 0); /* if not found in cache, do some I/O */ if ((bp->b_flags & B_CACHE) == 0) { if (curproc != NULL) curproc->p_stats->p_ru.ru_inblock++; bp->b_flags |= B_READ; bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); if (bp->b_rcred == NOCRED) { if (cred != NOCRED) crhold(cred); bp->b_rcred = cred; } vfs_busy_pages(bp, 0); VOP_STRATEGY(vp, bp); ++readwait; } for (i = 0; i < cnt; i++, rablkno++, rabsize++) { if (inmem(vp, *rablkno)) continue; rabp = getblk(vp, *rablkno, *rabsize, 0, 0); if ((rabp->b_flags & B_CACHE) == 0) { if (curproc != NULL) curproc->p_stats->p_ru.ru_inblock++; rabp->b_flags |= B_READ | B_ASYNC; rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); if (rabp->b_rcred == NOCRED) { if (cred != NOCRED) crhold(cred); rabp->b_rcred = cred; } vfs_busy_pages(rabp, 0); VOP_STRATEGY(vp, rabp); } else { brelse(rabp); } } if (readwait) { rv = biowait(bp); } return (rv); } /* * Write, release buffer on completion. (Done by iodone * if async.) */ int bwrite(struct buf * bp) { int oldflags, s; struct vnode *vp; struct mount *mp; if (bp->b_flags & B_INVAL) { brelse(bp); return (0); } oldflags = bp->b_flags; #if !defined(MAX_PERF) if ((bp->b_flags & B_BUSY) == 0) panic("bwrite: buffer is not busy???"); #endif bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI); bp->b_flags |= B_WRITEINPROG; s = splbio(); if ((oldflags & B_DELWRI) == B_DELWRI) { --numdirtybuffers; reassignbuf(bp, bp->b_vp); } bp->b_vp->v_numoutput++; vfs_busy_pages(bp, 1); if (curproc != NULL) curproc->p_stats->p_ru.ru_oublock++; splx(s); VOP_STRATEGY(bp->b_vp, bp); /* * Collect statistics on synchronous and asynchronous writes. * Writes to block devices are charged to their associated * filesystem (if any). */ if ((vp = bp->b_vp) != NULL) { if (vp->v_type == VBLK) mp = vp->v_specmountpoint; else mp = vp->v_mount; if (mp != NULL) if ((oldflags & B_ASYNC) == 0) mp->mnt_stat.f_syncwrites++; else mp->mnt_stat.f_asyncwrites++; } if ((oldflags & B_ASYNC) == 0) { int rtval = biowait(bp); brelse(bp); return (rtval); } return (0); } __inline void vfs_bio_need_satisfy(void) { ++numfreebuffers; if (!needsbuffer) return; if (numdirtybuffers < lodirtybuffers) { needsbuffer &= ~(VFS_BIO_NEED_ANY | VFS_BIO_NEED_LOWLIMIT); } else { needsbuffer &= ~VFS_BIO_NEED_ANY; } if (numfreebuffers >= hifreebuffers) { needsbuffer &= ~VFS_BIO_NEED_FREE; } wakeup(&needsbuffer); } /* * Delayed write. (Buffer is marked dirty). */ void bdwrite(struct buf * bp) { int s; struct vnode *vp; #if !defined(MAX_PERF) if ((bp->b_flags & B_BUSY) == 0) { panic("bdwrite: buffer is not busy"); } #endif if (bp->b_flags & B_INVAL) { brelse(bp); return; } bp->b_flags &= ~(B_READ|B_RELBUF); if ((bp->b_flags & B_DELWRI) == 0) { bp->b_flags |= B_DONE | B_DELWRI; reassignbuf(bp, bp->b_vp); ++numdirtybuffers; } /* * This bmap keeps the system from needing to do the bmap later, * perhaps when the system is attempting to do a sync. Since it * is likely that the indirect block -- or whatever other datastructure * that the filesystem needs is still in memory now, it is a good * thing to do this. Note also, that if the pageout daemon is * requesting a sync -- there might not be enough memory to do * the bmap then... So, this is important to do. */ if (bp->b_lblkno == bp->b_blkno) { VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); } /* * Set the *dirty* buffer range based upon the VM system dirty pages. */ vfs_setdirty(bp); /* * We need to do this here to satisfy the vnode_pager and the * pageout daemon, so that it thinks that the pages have been * "cleaned". Note that since the pages are in a delayed write * buffer -- the VFS layer "will" see that the pages get written * out on the next sync, or perhaps the cluster will be completed. */ vfs_clean_pages(bp); bqrelse(bp); /* * XXX The soft dependency code is not prepared to * have I/O done when a bdwrite is requested. For * now we just let the write be delayed if it is * requested by the soft dependency code. */ if ((vp = bp->b_vp) && (vp->v_type == VBLK && vp->v_specmountpoint && (vp->v_specmountpoint->mnt_flag & MNT_SOFTDEP)) || (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP))) return; if (numdirtybuffers >= hidirtybuffers) flushdirtybuffers(0, 0); return; } /* * Same as first half of bdwrite, mark buffer dirty, but do not release it. * Check how this compares with vfs_setdirty(); XXX [JRE] */ void bdirty(bp) struct buf *bp; { int s; bp->b_flags &= ~(B_READ|B_RELBUF); /* XXX ??? check this */ if ((bp->b_flags & B_DELWRI) == 0) { bp->b_flags |= B_DONE | B_DELWRI; /* why done? XXX JRE */ reassignbuf(bp, bp->b_vp); ++numdirtybuffers; } } /* * Asynchronous write. * Start output on a buffer, but do not wait for it to complete. * The buffer is released when the output completes. */ void bawrite(struct buf * bp) { bp->b_flags |= B_ASYNC; (void) VOP_BWRITE(bp); } /* * Ordered write. * Start output on a buffer, and flag it so that the device will write * it in the order it was queued. The buffer is released when the output * completes. */ int bowrite(struct buf * bp) { bp->b_flags |= B_ORDERED|B_ASYNC; return (VOP_BWRITE(bp)); } /* * Release a buffer. */ void brelse(struct buf * bp) { int s; if (bp->b_flags & B_CLUSTER) { relpbuf(bp); return; } s = splbio(); /* anyone need this block? */ if (bp->b_flags & B_WANTED) { bp->b_flags &= ~(B_WANTED | B_AGE); wakeup(bp); } if (bp->b_flags & B_LOCKED) bp->b_flags &= ~B_ERROR; if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_FREEBUF)) || (bp->b_bufsize <= 0)) { bp->b_flags |= B_INVAL; if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_deallocate) (*bioops.io_deallocate)(bp); if (bp->b_flags & B_DELWRI) --numdirtybuffers; bp->b_flags &= ~(B_DELWRI | B_CACHE | B_FREEBUF); if ((bp->b_flags & B_VMIO) == 0) { if (bp->b_bufsize) allocbuf(bp, 0); if (bp->b_vp) brelvp(bp); } } /* * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_release() * is called with B_DELWRI set, the underlying pages may wind up * getting freed causing a previous write (bdwrite()) to get 'lost' * because pages associated with a B_DELWRI bp are marked clean. * * We still allow the B_INVAL case to call vfs_vmio_release(), even * if B_DELWRI is set. */ if (bp->b_flags & B_DELWRI) bp->b_flags &= ~B_RELBUF; /* * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer * constituted, so the B_INVAL flag is used to *invalidate* the buffer, * but the VM object is kept around. The B_NOCACHE flag is used to * invalidate the pages in the VM object. * * If the buffer is a partially filled NFS buffer, keep it * since invalidating it now will lose informatio. The valid * flags in the vm_pages have only DEV_BSIZE resolution but * the b_validoff, b_validend fields have byte resolution. * This can avoid unnecessary re-reads of the buffer. * XXX this seems to cause performance problems. */ if ((bp->b_flags & B_VMIO) && !(bp->b_vp->v_tag == VT_NFS && bp->b_vp->v_type != VBLK && (bp->b_flags & B_DELWRI) != 0) #ifdef notdef && (bp->b_vp->v_tag != VT_NFS || bp->b_vp->v_type == VBLK || (bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) || bp->b_validend == 0 || (bp->b_validoff == 0 && bp->b_validend == bp->b_bufsize)) #endif ) { int i, j, resid; vm_page_t m; off_t foff; vm_pindex_t poff; vm_object_t obj; struct vnode *vp; vp = bp->b_vp; resid = bp->b_bufsize; foff = bp->b_offset; for (i = 0; i < bp->b_npages; i++) { m = bp->b_pages[i]; vm_page_flag_clear(m, PG_ZERO); if (m == bogus_page) { obj = (vm_object_t) vp->v_object; poff = OFF_TO_IDX(bp->b_offset); for (j = i; j < bp->b_npages; j++) { m = bp->b_pages[j]; if (m == bogus_page) { m = vm_page_lookup(obj, poff + j); #if !defined(MAX_PERF) if (!m) { panic("brelse: page missing\n"); } #endif bp->b_pages[j] = m; } } if ((bp->b_flags & B_INVAL) == 0) { pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); } } if (bp->b_flags & (B_NOCACHE|B_ERROR)) { int poffset = foff & PAGE_MASK; int presid = resid > (PAGE_SIZE - poffset) ? (PAGE_SIZE - poffset) : resid; vm_page_set_invalid(m, poffset, presid); } resid -= PAGE_SIZE; } if (bp->b_flags & (B_INVAL | B_RELBUF)) vfs_vmio_release(bp); } else if (bp->b_flags & B_VMIO) { if (bp->b_flags & (B_INVAL | B_RELBUF)) vfs_vmio_release(bp); } #if !defined(MAX_PERF) if (bp->b_qindex != QUEUE_NONE) panic("brelse: free buffer onto another queue???"); #endif /* enqueue */ /* buffers with no memory */ if (bp->b_bufsize == 0) { bp->b_flags |= B_INVAL; bp->b_qindex = QUEUE_EMPTY; TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist); LIST_REMOVE(bp, b_hash); LIST_INSERT_HEAD(&invalhash, bp, b_hash); bp->b_dev = NODEV; kvafreespace += bp->b_kvasize; /* buffers with junk contents */ } else if (bp->b_flags & (B_ERROR | B_INVAL | B_NOCACHE | B_RELBUF)) { bp->b_flags |= B_INVAL; bp->b_qindex = QUEUE_AGE; TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist); LIST_REMOVE(bp, b_hash); LIST_INSERT_HEAD(&invalhash, bp, b_hash); bp->b_dev = NODEV; /* buffers that are locked */ } else if (bp->b_flags & B_LOCKED) { bp->b_qindex = QUEUE_LOCKED; TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); /* buffers with stale but valid contents */ } else if (bp->b_flags & B_AGE) { bp->b_qindex = QUEUE_AGE; TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist); /* buffers with valid and quite potentially reuseable contents */ } else { bp->b_qindex = QUEUE_LRU; TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); } if ((bp->b_flags & B_INVAL) || (bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { if (bp->b_flags & B_DELWRI) { --numdirtybuffers; bp->b_flags &= ~B_DELWRI; } vfs_bio_need_satisfy(); } /* unlock */ bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); splx(s); } /* * Release a buffer. */ void bqrelse(struct buf * bp) { int s; s = splbio(); /* anyone need this block? */ if (bp->b_flags & B_WANTED) { bp->b_flags &= ~(B_WANTED | B_AGE); wakeup(bp); } #if !defined(MAX_PERF) if (bp->b_qindex != QUEUE_NONE) panic("bqrelse: free buffer onto another queue???"); #endif if (bp->b_flags & B_LOCKED) { bp->b_flags &= ~B_ERROR; bp->b_qindex = QUEUE_LOCKED; TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); /* buffers with stale but valid contents */ } else { bp->b_qindex = QUEUE_LRU; TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); } if ((bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { vfs_bio_need_satisfy(); } /* unlock */ bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); splx(s); } static void vfs_vmio_release(bp) struct buf *bp; { int i; vm_page_t m; for (i = 0; i < bp->b_npages; i++) { m = bp->b_pages[i]; bp->b_pages[i] = NULL; vm_page_unwire(m); /* * We don't mess with busy pages, it is * the responsibility of the process that * busied the pages to deal with them. */ if ((m->flags & PG_BUSY) || (m->busy != 0)) continue; if (m->wire_count == 0) { /* * If this is an async free -- we cannot place * pages onto the cache queue. If it is an * async free, then we don't modify any queues. * This is probably in error (for perf reasons), * and we will eventually need to build * a more complete infrastructure to support I/O * rundown. */ if ((bp->b_flags & B_ASYNC) == 0) { /* * In the case of sync buffer frees, we can do pretty much * anything to any of the memory queues. Specifically, * the cache queue is okay to be modified. */ if (m->valid) { if(m->dirty == 0) vm_page_test_dirty(m); /* * this keeps pressure off of the process memory */ if (m->dirty == 0 && m->hold_count == 0) vm_page_cache(m); else vm_page_deactivate(m); vm_page_flag_clear(m, PG_ZERO); } else if (m->hold_count == 0) { vm_page_busy(m); vm_page_protect(m, VM_PROT_NONE); vm_page_free(m); } } else { /* * If async, then at least we clear the * act_count. */ m->act_count = 0; vm_page_flag_clear(m, PG_ZERO); } } } bufspace -= bp->b_bufsize; vmiospace -= bp->b_bufsize; pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); bp->b_npages = 0; bp->b_bufsize = 0; bp->b_flags &= ~B_VMIO; if (bp->b_vp) brelvp(bp); } /* * Check to see if a block is currently memory resident. */ struct buf * gbincore(struct vnode * vp, daddr_t blkno) { struct buf *bp; struct bufhashhdr *bh; bh = BUFHASH(vp, blkno); bp = bh->lh_first; /* Search hash chain */ while (bp != NULL) { /* hit */ if (bp->b_vp == vp && bp->b_lblkno == blkno && (bp->b_flags & B_INVAL) == 0) { break; } bp = bp->b_hash.le_next; } return (bp); } /* * this routine implements clustered async writes for * clearing out B_DELWRI buffers... This is much better * than the old way of writing only one buffer at a time. */ int vfs_bio_awrite(struct buf * bp) { int i; daddr_t lblkno = bp->b_lblkno; struct vnode *vp = bp->b_vp; int s; int ncl; struct buf *bpa; int nwritten; int size; int maxcl; s = splbio(); /* * right now we support clustered writing only to regular files */ if ((vp->v_type == VREG) && (vp->v_mount != 0) && /* Only on nodes that have the size info */ (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { size = vp->v_mount->mnt_stat.f_iosize; maxcl = MAXPHYS / size; for (i = 1; i < maxcl; i++) { if ((bpa = gbincore(vp, lblkno + i)) && ((bpa->b_flags & (B_BUSY | B_DELWRI | B_CLUSTEROK | B_INVAL)) == (B_DELWRI | B_CLUSTEROK)) && (bpa->b_bufsize == size)) { if ((bpa->b_blkno == bpa->b_lblkno) || (bpa->b_blkno != bp->b_blkno + ((i * size) >> DEV_BSHIFT))) break; } else { break; } } ncl = i; /* * this is a possible cluster write */ if (ncl != 1) { nwritten = cluster_wbuild(vp, size, lblkno, ncl); splx(s); return nwritten; } } bremfree(bp); bp->b_flags |= B_BUSY | B_ASYNC; splx(s); /* * default (old) behavior, writing out only one block */ nwritten = bp->b_bufsize; (void) VOP_BWRITE(bp); return nwritten; } /* * Find a buffer header which is available for use. */ static struct buf * getnewbuf(struct vnode *vp, daddr_t blkno, int slpflag, int slptimeo, int size, int maxsize) { struct buf *bp, *bp1; int nbyteswritten = 0; vm_offset_t addr; static int writerecursion = 0; start: if (bufspace >= maxbufspace) goto trytofreespace; /* can we constitute a new buffer? */ if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]))) { #if !defined(MAX_PERF) if (bp->b_qindex != QUEUE_EMPTY) panic("getnewbuf: inconsistent EMPTY queue, qindex=%d", bp->b_qindex); #endif bp->b_flags |= B_BUSY; bremfree(bp); goto fillbuf; } trytofreespace: /* * We keep the file I/O from hogging metadata I/O * This is desirable because file data is cached in the * VM/Buffer cache even if a buffer is freed. */ if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]))) { #if !defined(MAX_PERF) if (bp->b_qindex != QUEUE_AGE) panic("getnewbuf: inconsistent AGE queue, qindex=%d", bp->b_qindex); #endif } else if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]))) { #if !defined(MAX_PERF) if (bp->b_qindex != QUEUE_LRU) panic("getnewbuf: inconsistent LRU queue, qindex=%d", bp->b_qindex); #endif } if (!bp) { /* wait for a free buffer of any kind */ needsbuffer |= VFS_BIO_NEED_ANY; do tsleep(&needsbuffer, (PRIBIO + 4) | slpflag, "newbuf", slptimeo); while (needsbuffer & VFS_BIO_NEED_ANY); return (0); } #if defined(DIAGNOSTIC) if (bp->b_flags & B_BUSY) { panic("getnewbuf: busy buffer on free list\n"); } #endif /* * We are fairly aggressive about freeing VMIO buffers, but since * the buffering is intact without buffer headers, there is not * much loss. We gain by maintaining non-VMIOed metadata in buffers. */ if ((bp->b_qindex == QUEUE_LRU) && (bp->b_usecount > 0)) { if ((bp->b_flags & B_VMIO) == 0 || (vmiospace < maxvmiobufspace)) { --bp->b_usecount; TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist); if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) { TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); goto start; } TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); } } /* if we are a delayed write, convert to an async write */ if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) { /* * If our delayed write is likely to be used soon, then * recycle back onto the LRU queue. */ if (vp && (bp->b_vp == vp) && (bp->b_qindex == QUEUE_LRU) && (bp->b_lblkno >= blkno) && (maxsize > 0)) { if (bp->b_usecount > 0) { if (bp->b_lblkno < blkno + (MAXPHYS / maxsize)) { TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist); if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) { TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); bp->b_usecount--; goto start; } TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); } } } /* * Certain layered filesystems can recursively re-enter the vfs_bio * code, due to delayed writes. This helps keep the system from * deadlocking. */ if (writerecursion > 0) { if (writerecursion > 5) { bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); while (bp) { if ((bp->b_flags & B_DELWRI) == 0) break; bp = TAILQ_NEXT(bp, b_freelist); } if (bp == NULL) { bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); while (bp) { if ((bp->b_flags & B_DELWRI) == 0) break; bp = TAILQ_NEXT(bp, b_freelist); } } if (bp == NULL) panic("getnewbuf: cannot get buffer, infinite recursion failure"); } else { bremfree(bp); bp->b_flags |= B_BUSY | B_AGE | B_ASYNC; nbyteswritten += bp->b_bufsize; ++writerecursion; VOP_BWRITE(bp); --writerecursion; if (!slpflag && !slptimeo) { return (0); } goto start; } } else { ++writerecursion; nbyteswritten += vfs_bio_awrite(bp); --writerecursion; if (!slpflag && !slptimeo) { return (0); } goto start; } } if (bp->b_flags & B_WANTED) { bp->b_flags &= ~B_WANTED; wakeup(bp); } bremfree(bp); bp->b_flags |= B_BUSY; if (bp->b_flags & B_VMIO) { bp->b_flags &= ~B_ASYNC; vfs_vmio_release(bp); } if (bp->b_vp) brelvp(bp); fillbuf: /* we are not free, nor do we contain interesting data */ if (bp->b_rcred != NOCRED) { crfree(bp->b_rcred); bp->b_rcred = NOCRED; } if (bp->b_wcred != NOCRED) { crfree(bp->b_wcred); bp->b_wcred = NOCRED; } if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_deallocate) (*bioops.io_deallocate)(bp); LIST_REMOVE(bp, b_hash); LIST_INSERT_HEAD(&invalhash, bp, b_hash); if (bp->b_bufsize) { allocbuf(bp, 0); } bp->b_flags = B_BUSY; bp->b_dev = NODEV; bp->b_vp = NULL; bp->b_blkno = bp->b_lblkno = 0; bp->b_offset = NOOFFSET; bp->b_iodone = 0; bp->b_error = 0; bp->b_resid = 0; bp->b_bcount = 0; bp->b_npages = 0; bp->b_dirtyoff = bp->b_dirtyend = 0; bp->b_validoff = bp->b_validend = 0; bp->b_usecount = 5; /* Here, not kern_physio.c, is where this should be done*/ LIST_INIT(&bp->b_dep); maxsize = (maxsize + PAGE_MASK) & ~PAGE_MASK; /* * we assume that buffer_map is not at address 0 */ addr = 0; if (maxsize != bp->b_kvasize) { bfreekva(bp); findkvaspace: /* * See if we have buffer kva space */ if (vm_map_findspace(buffer_map, vm_map_min(buffer_map), maxsize, &addr)) { if (kvafreespace > 0) { int totfree = 0, freed; do { freed = 0; for (bp1 = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]); bp1 != NULL; bp1 = TAILQ_NEXT(bp1, b_freelist)) { if (bp1->b_kvasize != 0) { totfree += bp1->b_kvasize; freed = bp1->b_kvasize; bremfree(bp1); bfreekva(bp1); brelse(bp1); break; } } } while (freed); /* * if we found free space, then retry with the same buffer. */ if (totfree) goto findkvaspace; } bp->b_flags |= B_INVAL; brelse(bp); goto trytofreespace; } } /* * See if we are below are allocated minimum */ if (bufspace >= (maxbufspace + nbyteswritten)) { bp->b_flags |= B_INVAL; brelse(bp); goto trytofreespace; } /* * create a map entry for the buffer -- in essence * reserving the kva space. */ if (addr) { vm_map_insert(buffer_map, NULL, 0, addr, addr + maxsize, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); bp->b_kvabase = (caddr_t) addr; bp->b_kvasize = maxsize; } bp->b_data = bp->b_kvabase; return (bp); } static void waitfreebuffers(int slpflag, int slptimeo) { while (numfreebuffers < hifreebuffers) { flushdirtybuffers(slpflag, slptimeo); if (numfreebuffers < hifreebuffers) break; needsbuffer |= VFS_BIO_NEED_FREE; if (tsleep(&needsbuffer, (PRIBIO + 4)|slpflag, "biofre", slptimeo)) break; } } static void flushdirtybuffers(int slpflag, int slptimeo) { int s; static pid_t flushing = 0; s = splbio(); if (flushing) { if (flushing == curproc->p_pid) { splx(s); return; } while (flushing) { if (tsleep(&flushing, (PRIBIO + 4)|slpflag, "biofls", slptimeo)) { splx(s); return; } } } flushing = curproc->p_pid; while (numdirtybuffers > lodirtybuffers) { struct buf *bp; needsbuffer |= VFS_BIO_NEED_LOWLIMIT; bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); if (bp == NULL) bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); while (bp && ((bp->b_flags & B_DELWRI) == 0)) { bp = TAILQ_NEXT(bp, b_freelist); } if (bp) { vfs_bio_awrite(bp); continue; } break; } flushing = 0; wakeup(&flushing); splx(s); } /* * Check to see if a block is currently memory resident. */ struct buf * incore(struct vnode * vp, daddr_t blkno) { struct buf *bp; int s = splbio(); bp = gbincore(vp, blkno); splx(s); return (bp); } /* * Returns true if no I/O is needed to access the * associated VM object. This is like incore except * it also hunts around in the VM system for the data. */ int inmem(struct vnode * vp, daddr_t blkno) { vm_object_t obj; vm_offset_t toff, tinc; vm_page_t m; vm_ooffset_t off; if (incore(vp, blkno)) return 1; if (vp->v_mount == NULL) return 0; if ((vp->v_object == NULL) || (vp->v_flag & VOBJBUF) == 0) return 0; obj = vp->v_object; tinc = PAGE_SIZE; if (tinc > vp->v_mount->mnt_stat.f_iosize) tinc = vp->v_mount->mnt_stat.f_iosize; off = blkno * vp->v_mount->mnt_stat.f_iosize; for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { m = vm_page_lookup(obj, OFF_TO_IDX(off + toff)); if (!m) return 0; if (vm_page_is_valid(m, (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0) return 0; } return 1; } /* * now we set the dirty range for the buffer -- * for NFS -- if the file is mapped and pages have * been written to, let it know. We want the * entire range of the buffer to be marked dirty if * any of the pages have been written to for consistancy * with the b_validoff, b_validend set in the nfs write * code, and used by the nfs read code. */ static void vfs_setdirty(struct buf *bp) { int i; vm_object_t object; vm_offset_t boffset, offset; /* * We qualify the scan for modified pages on whether the * object has been flushed yet. The OBJ_WRITEABLE flag * is not cleared simply by protecting pages off. */ if ((bp->b_flags & B_VMIO) && ((object = bp->b_pages[0]->object)->flags & (OBJ_WRITEABLE|OBJ_CLEANING))) { /* * test the pages to see if they have been modified directly * by users through the VM system. */ for (i = 0; i < bp->b_npages; i++) { vm_page_flag_clear(bp->b_pages[i], PG_ZERO); vm_page_test_dirty(bp->b_pages[i]); } /* * scan forwards for the first page modified */ for (i = 0; i < bp->b_npages; i++) { if (bp->b_pages[i]->dirty) { break; } } boffset = (i << PAGE_SHIFT); if (boffset < bp->b_dirtyoff) { bp->b_dirtyoff = boffset; } /* * scan backwards for the last page modified */ for (i = bp->b_npages - 1; i >= 0; --i) { if (bp->b_pages[i]->dirty) { break; } } boffset = (i + 1); offset = boffset + bp->b_pages[0]->pindex; if (offset >= object->size) boffset = object->size - bp->b_pages[0]->pindex; if (bp->b_dirtyend < (boffset << PAGE_SHIFT)) bp->b_dirtyend = (boffset << PAGE_SHIFT); } } /* * Get a block given a specified block and offset into a file/device. */ struct buf * getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo) { struct buf *bp; int i, s; struct bufhashhdr *bh; int maxsize; int generation; int checksize; if (vp->v_mount) { maxsize = vp->v_mount->mnt_stat.f_iosize; /* * This happens on mount points. */ if (maxsize < size) maxsize = size; } else { maxsize = size; } #if !defined(MAX_PERF) if (size > MAXBSIZE) panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE); #endif s = splbio(); loop: if (numfreebuffers < lofreebuffers) { waitfreebuffers(slpflag, slptimeo); } if ((bp = gbincore(vp, blkno))) { loop1: if (bp->b_flags & B_BUSY) { bp->b_flags |= B_WANTED; if (bp->b_usecount < BUF_MAXUSE) ++bp->b_usecount; if (!tsleep(bp, (PRIBIO + 4) | slpflag, "getblk", slptimeo)) { goto loop; } splx(s); return (struct buf *) NULL; } bp->b_flags |= B_BUSY | B_CACHE; bremfree(bp); /* * check for size inconsistancies (note that they shouldn't * happen but do when filesystems don't handle the size changes * correctly.) We are conservative on metadata and don't just * extend the buffer but write (if needed) and re-constitute it. */ if (bp->b_bcount != size) { if ((bp->b_flags & B_VMIO) && (size <= bp->b_kvasize)) { allocbuf(bp, size); } else { if (bp->b_flags & B_DELWRI) { bp->b_flags |= B_NOCACHE; VOP_BWRITE(bp); } else { if ((bp->b_flags & B_VMIO) && (LIST_FIRST(&bp->b_dep) == NULL)) { bp->b_flags |= B_RELBUF; brelse(bp); } else { bp->b_flags |= B_NOCACHE; VOP_BWRITE(bp); } } goto loop; } } #ifdef DIAGNOSTIC if (bp->b_offset == NOOFFSET) panic("getblk: no buffer offset"); #endif /* * Check that the constituted buffer really deserves for the * B_CACHE bit to be set. B_VMIO type buffers might not * contain fully valid pages. Normal (old-style) buffers * should be fully valid. */ if (bp->b_flags & B_VMIO) { checksize = bp->b_bufsize; for (i = 0; i < bp->b_npages; i++) { int resid; int poffset; poffset = bp->b_offset & PAGE_MASK; resid = (checksize > (PAGE_SIZE - poffset)) ? (PAGE_SIZE - poffset) : checksize; if (!vm_page_is_valid(bp->b_pages[i], poffset, resid)) { bp->b_flags &= ~(B_CACHE | B_DONE); break; } checksize -= resid; } } if (bp->b_usecount < BUF_MAXUSE) ++bp->b_usecount; splx(s); return (bp); } else { vm_object_t obj; if ((bp = getnewbuf(vp, blkno, slpflag, slptimeo, size, maxsize)) == 0) { if (slpflag || slptimeo) { splx(s); return NULL; } goto loop; } /* * This code is used to make sure that a buffer is not * created while the getnewbuf routine is blocked. * Normally the vnode is locked so this isn't a problem. * VBLK type I/O requests, however, don't lock the vnode. */ if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE && gbincore(vp, blkno)) { bp->b_flags |= B_INVAL; brelse(bp); goto loop; } /* * Insert the buffer into the hash, so that it can * be found by incore. */ bp->b_blkno = bp->b_lblkno = blkno; if (vp->v_type != VBLK) bp->b_offset = (off_t) blkno * maxsize; else bp->b_offset = (off_t) blkno * DEV_BSIZE; bgetvp(vp, bp); LIST_REMOVE(bp, b_hash); bh = BUFHASH(vp, blkno); LIST_INSERT_HEAD(bh, bp, b_hash); if ((obj = vp->v_object) && (vp->v_flag & VOBJBUF)) { bp->b_flags |= (B_VMIO | B_CACHE); #if defined(VFS_BIO_DEBUG) if (vp->v_type != VREG && vp->v_type != VBLK) printf("getblk: vmioing file type %d???\n", vp->v_type); #endif } else { bp->b_flags &= ~B_VMIO; } allocbuf(bp, size); splx(s); return (bp); } } /* * Get an empty, disassociated buffer of given size. */ struct buf * geteblk(int size) { struct buf *bp; int s; s = splbio(); while ((bp = getnewbuf(0, (daddr_t) 0, 0, 0, size, MAXBSIZE)) == 0); splx(s); allocbuf(bp, size); bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ return (bp); } /* * This code constitutes the buffer memory from either anonymous system * memory (in the case of non-VMIO operations) or from an associated * VM object (in the case of VMIO operations). * * Note that this code is tricky, and has many complications to resolve * deadlock or inconsistant data situations. Tread lightly!!! * * Modify the length of a buffer's underlying buffer storage without * destroying information (unless, of course the buffer is shrinking). */ int allocbuf(struct buf * bp, int size) { int s; int newbsize, mbsize; int i; #if !defined(MAX_PERF) if (!(bp->b_flags & B_BUSY)) panic("allocbuf: buffer not busy"); if (bp->b_kvasize < size) panic("allocbuf: buffer too small"); #endif if ((bp->b_flags & B_VMIO) == 0) { caddr_t origbuf; int origbufsize; /* * Just get anonymous memory from the kernel */ mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); #if !defined(NO_B_MALLOC) if (bp->b_flags & B_MALLOC) newbsize = mbsize; else #endif newbsize = round_page(size); if (newbsize < bp->b_bufsize) { #if !defined(NO_B_MALLOC) /* * malloced buffers are not shrunk */ if (bp->b_flags & B_MALLOC) { if (newbsize) { bp->b_bcount = size; } else { free(bp->b_data, M_BIOBUF); bufspace -= bp->b_bufsize; bufmallocspace -= bp->b_bufsize; bp->b_data = bp->b_kvabase; bp->b_bufsize = 0; bp->b_bcount = 0; bp->b_flags &= ~B_MALLOC; } return 1; } #endif vm_hold_free_pages( bp, (vm_offset_t) bp->b_data + newbsize, (vm_offset_t) bp->b_data + bp->b_bufsize); } else if (newbsize > bp->b_bufsize) { #if !defined(NO_B_MALLOC) /* * We only use malloced memory on the first allocation. * and revert to page-allocated memory when the buffer grows. */ if ( (bufmallocspace < maxbufmallocspace) && (bp->b_bufsize == 0) && (mbsize <= PAGE_SIZE/2)) { bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK); bp->b_bufsize = mbsize; bp->b_bcount = size; bp->b_flags |= B_MALLOC; bufspace += mbsize; bufmallocspace += mbsize; return 1; } #endif origbuf = NULL; origbufsize = 0; #if !defined(NO_B_MALLOC) /* * If the buffer is growing on its other-than-first allocation, * then we revert to the page-allocation scheme. */ if (bp->b_flags & B_MALLOC) { origbuf = bp->b_data; origbufsize = bp->b_bufsize; bp->b_data = bp->b_kvabase; bufspace -= bp->b_bufsize; bufmallocspace -= bp->b_bufsize; bp->b_bufsize = 0; bp->b_flags &= ~B_MALLOC; newbsize = round_page(newbsize); } #endif vm_hold_load_pages( bp, (vm_offset_t) bp->b_data + bp->b_bufsize, (vm_offset_t) bp->b_data + newbsize); #if !defined(NO_B_MALLOC) if (origbuf) { bcopy(origbuf, bp->b_data, origbufsize); free(origbuf, M_BIOBUF); } #endif } } else { vm_page_t m; int desiredpages; newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); desiredpages = (round_page(newbsize) >> PAGE_SHIFT); #if !defined(NO_B_MALLOC) if (bp->b_flags & B_MALLOC) panic("allocbuf: VMIO buffer can't be malloced"); #endif if (newbsize < bp->b_bufsize) { if (desiredpages < bp->b_npages) { for (i = desiredpages; i < bp->b_npages; i++) { /* * the page is not freed here -- it * is the responsibility of vnode_pager_setsize */ m = bp->b_pages[i]; #if defined(DIAGNOSTIC) if (m == bogus_page) panic("allocbuf: bogus page found"); #endif vm_page_sleep(m, "biodep", &m->busy); bp->b_pages[i] = NULL; vm_page_unwire(m); } pmap_qremove((vm_offset_t) trunc_page(bp->b_data) + (desiredpages << PAGE_SHIFT), (bp->b_npages - desiredpages)); bp->b_npages = desiredpages; } } else if (newbsize > bp->b_bufsize) { vm_object_t obj; vm_offset_t tinc, toff; vm_ooffset_t off; vm_pindex_t objoff; int pageindex, curbpnpages; struct vnode *vp; int bsize; int orig_validoff = bp->b_validoff; int orig_validend = bp->b_validend; vp = bp->b_vp; if (vp->v_type == VBLK) bsize = DEV_BSIZE; else bsize = vp->v_mount->mnt_stat.f_iosize; if (bp->b_npages < desiredpages) { obj = vp->v_object; tinc = PAGE_SIZE; if (tinc > bsize) tinc = bsize; off = bp->b_offset; #ifdef DIAGNOSTIC if (bp->b_offset == NOOFFSET) panic("allocbuf: no buffer offset"); #endif curbpnpages = bp->b_npages; doretry: bp->b_validoff = orig_validoff; bp->b_validend = orig_validend; bp->b_flags |= B_CACHE; for (toff = 0; toff < newbsize; toff += tinc) { int bytesinpage; pageindex = toff >> PAGE_SHIFT; objoff = OFF_TO_IDX(off + toff); if (pageindex < curbpnpages) { m = bp->b_pages[pageindex]; #ifdef VFS_BIO_DIAG if (m->pindex != objoff) panic("allocbuf: page changed offset??!!!?"); #endif bytesinpage = tinc; if (tinc > (newbsize - toff)) bytesinpage = newbsize - toff; if (bp->b_flags & B_CACHE) vfs_buf_set_valid(bp, off, toff, bytesinpage, m); continue; } m = vm_page_lookup(obj, objoff); if (!m) { m = vm_page_alloc(obj, objoff, VM_ALLOC_NORMAL); if (!m) { VM_WAIT; vm_pageout_deficit += (desiredpages - bp->b_npages); goto doretry; } vm_page_wire(m); vm_page_flag_clear(m, PG_BUSY); bp->b_flags &= ~B_CACHE; } else if (m->flags & PG_BUSY) { s = splvm(); if (m->flags & PG_BUSY) { vm_page_flag_set(m, PG_WANTED); tsleep(m, PVM, "pgtblk", 0); } splx(s); goto doretry; } else { if ((curproc != pageproc) && ((m->queue - m->pc) == PQ_CACHE) && ((cnt.v_free_count + cnt.v_cache_count) < (cnt.v_free_min + cnt.v_cache_min))) { pagedaemon_wakeup(); } bytesinpage = tinc; if (tinc > (newbsize - toff)) bytesinpage = newbsize - toff; if (bp->b_flags & B_CACHE) vfs_buf_set_valid(bp, off, toff, bytesinpage, m); vm_page_flag_clear(m, PG_ZERO); vm_page_wire(m); } bp->b_pages[pageindex] = m; curbpnpages = pageindex + 1; } if (vp->v_tag == VT_NFS && vp->v_type != VBLK) { if (bp->b_dirtyend > 0) { bp->b_validoff = min(bp->b_validoff, bp->b_dirtyoff); bp->b_validend = max(bp->b_validend, bp->b_dirtyend); } if (bp->b_validend == 0) bp->b_flags &= ~B_CACHE; } bp->b_data = (caddr_t) trunc_page(bp->b_data); bp->b_npages = curbpnpages; pmap_qenter((vm_offset_t) bp->b_data, bp->b_pages, bp->b_npages); ((vm_offset_t) bp->b_data) |= off & PAGE_MASK; } } } if (bp->b_flags & B_VMIO) vmiospace += (newbsize - bp->b_bufsize); bufspace += (newbsize - bp->b_bufsize); bp->b_bufsize = newbsize; bp->b_bcount = size; return 1; } /* * Wait for buffer I/O completion, returning error status. */ int biowait(register struct buf * bp) { int s; s = splbio(); while ((bp->b_flags & B_DONE) == 0) #if defined(NO_SCHEDULE_MODS) tsleep(bp, PRIBIO, "biowait", 0); #else if (bp->b_flags & B_READ) tsleep(bp, PRIBIO, "biord", 0); else tsleep(bp, PRIBIO, "biowr", 0); #endif splx(s); if (bp->b_flags & B_EINTR) { bp->b_flags &= ~B_EINTR; return (EINTR); } if (bp->b_flags & B_ERROR) { return (bp->b_error ? bp->b_error : EIO); } else { return (0); } } /* * Finish I/O on a buffer, calling an optional function. * This is usually called from interrupt level, so process blocking * is not *a good idea*. */ void biodone(register struct buf * bp) { int s; s = splbio(); #if !defined(MAX_PERF) if (!(bp->b_flags & B_BUSY)) panic("biodone: buffer not busy"); #endif if (bp->b_flags & B_DONE) { splx(s); #if !defined(MAX_PERF) printf("biodone: buffer already done\n"); #endif return; } bp->b_flags |= B_DONE; if (bp->b_flags & B_FREEBUF) { brelse(bp); splx(s); return; } if ((bp->b_flags & B_READ) == 0) { vwakeup(bp); } /* call optional completion function if requested */ if (bp->b_flags & B_CALL) { bp->b_flags &= ~B_CALL; (*bp->b_iodone) (bp); splx(s); return; } if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete) (*bioops.io_complete)(bp); if (bp->b_flags & B_VMIO) { int i, resid; vm_ooffset_t foff; vm_page_t m; vm_object_t obj; int iosize; struct vnode *vp = bp->b_vp; obj = vp->v_object; #if defined(VFS_BIO_DEBUG) if (vp->v_usecount == 0) { panic("biodone: zero vnode ref count"); } if (vp->v_object == NULL) { panic("biodone: missing VM object"); } if ((vp->v_flag & VOBJBUF) == 0) { panic("biodone: vnode is not setup for merged cache"); } #endif foff = bp->b_offset; #ifdef DIAGNOSTIC if (bp->b_offset == NOOFFSET) panic("biodone: no buffer offset"); #endif #if !defined(MAX_PERF) if (!obj) { panic("biodone: no object"); } #endif #if defined(VFS_BIO_DEBUG) if (obj->paging_in_progress < bp->b_npages) { printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n", obj->paging_in_progress, bp->b_npages); } #endif iosize = bp->b_bufsize; for (i = 0; i < bp->b_npages; i++) { int bogusflag = 0; m = bp->b_pages[i]; if (m == bogus_page) { bogusflag = 1; m = vm_page_lookup(obj, OFF_TO_IDX(foff)); if (!m) { #if defined(VFS_BIO_DEBUG) printf("biodone: page disappeared\n"); #endif vm_object_pip_subtract(obj, 1); continue; } bp->b_pages[i] = m; pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); } #if defined(VFS_BIO_DEBUG) if (OFF_TO_IDX(foff) != m->pindex) { printf("biodone: foff(%d)/m->pindex(%d) mismatch\n", foff, m->pindex); } #endif resid = IDX_TO_OFF(m->pindex + 1) - foff; if (resid > iosize) resid = iosize; /* * In the write case, the valid and clean bits are * already changed correctly, so we only need to do this * here in the read case. */ if ((bp->b_flags & B_READ) && !bogusflag && resid > 0) { vfs_page_set_valid(bp, foff, i, m); } vm_page_flag_clear(m, PG_ZERO); /* * when debugging new filesystems or buffer I/O methods, this * is the most common error that pops up. if you see this, you * have not set the page busy flag correctly!!! */ if (m->busy == 0) { #if !defined(MAX_PERF) printf("biodone: page busy < 0, " "pindex: %d, foff: 0x(%x,%x), " "resid: %d, index: %d\n", (int) m->pindex, (int)(foff >> 32), (int) foff & 0xffffffff, resid, i); #endif if (vp->v_type != VBLK) #if !defined(MAX_PERF) printf(" iosize: %ld, lblkno: %d, flags: 0x%lx, npages: %d\n", bp->b_vp->v_mount->mnt_stat.f_iosize, (int) bp->b_lblkno, bp->b_flags, bp->b_npages); else printf(" VDEV, lblkno: %d, flags: 0x%lx, npages: %d\n", (int) bp->b_lblkno, bp->b_flags, bp->b_npages); printf(" valid: 0x%x, dirty: 0x%x, wired: %d\n", m->valid, m->dirty, m->wire_count); #endif panic("biodone: page busy < 0\n"); } vm_page_io_finish(m); vm_object_pip_subtract(obj, 1); foff += resid; iosize -= resid; } if (obj && (obj->paging_in_progress == 0) && (obj->flags & OBJ_PIPWNT)) { vm_object_clear_flag(obj, OBJ_PIPWNT); wakeup(obj); } } /* * For asynchronous completions, release the buffer now. The brelse * checks for B_WANTED and will do the wakeup there if necessary - so * no need to do a wakeup here in the async case. */ if (bp->b_flags & B_ASYNC) { if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0) brelse(bp); else bqrelse(bp); } else { bp->b_flags &= ~B_WANTED; wakeup(bp); } splx(s); } static int count_lock_queue() { int count; struct buf *bp; count = 0; for (bp = TAILQ_FIRST(&bufqueues[QUEUE_LOCKED]); bp != NULL; bp = TAILQ_NEXT(bp, b_freelist)) count++; return (count); } #if 0 /* not with kirks code */ static int vfs_update_interval = 30; static void vfs_update() { while (1) { tsleep(&vfs_update_wakeup, PUSER, "update", hz * vfs_update_interval); vfs_update_wakeup = 0; sync(curproc, NULL); } } static int sysctl_kern_updateinterval SYSCTL_HANDLER_ARGS { int error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); if (!error) wakeup(&vfs_update_wakeup); return error; } SYSCTL_PROC(_kern, KERN_UPDATEINTERVAL, update, CTLTYPE_INT|CTLFLAG_RW, &vfs_update_interval, 0, sysctl_kern_updateinterval, "I", ""); #endif /* * This routine is called in lieu of iodone in the case of * incomplete I/O. This keeps the busy status for pages * consistant. */ void vfs_unbusy_pages(struct buf * bp) { int i, s; if (bp->b_flags & B_VMIO) { struct vnode *vp = bp->b_vp; vm_object_t obj = vp->v_object; for (i = 0; i < bp->b_npages; i++) { vm_page_t m = bp->b_pages[i]; if (m == bogus_page) { m = vm_page_lookup(obj, OFF_TO_IDX(bp->b_offset) + i); #if !defined(MAX_PERF) if (!m) { panic("vfs_unbusy_pages: page missing\n"); } #endif bp->b_pages[i] = m; pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); } vm_object_pip_subtract(obj, 1); vm_page_flag_clear(m, PG_ZERO); vm_page_io_finish(m); } if (obj->paging_in_progress == 0 && (obj->flags & OBJ_PIPWNT)) { vm_object_clear_flag(obj, OBJ_PIPWNT); wakeup(obj); } } } /* * Set NFS' b_validoff and b_validend fields from the valid bits * of a page. If the consumer is not NFS, and the page is not * valid for the entire range, clear the B_CACHE flag to force * the consumer to re-read the page. */ static void vfs_buf_set_valid(struct buf *bp, vm_ooffset_t foff, vm_offset_t off, vm_offset_t size, vm_page_t m) { if (bp->b_vp->v_tag == VT_NFS && bp->b_vp->v_type != VBLK) { vm_offset_t svalid, evalid; int validbits = m->valid; /* * This only bothers with the first valid range in the * page. */ svalid = off; while (validbits && !(validbits & 1)) { svalid += DEV_BSIZE; validbits >>= 1; } evalid = svalid; while (validbits & 1) { evalid += DEV_BSIZE; validbits >>= 1; } /* * Make sure this range is contiguous with the range * built up from previous pages. If not, then we will * just use the range from the previous pages. */ if (svalid == bp->b_validend) { bp->b_validoff = min(bp->b_validoff, svalid); bp->b_validend = max(bp->b_validend, evalid); } } else if (!vm_page_is_valid(m, (vm_offset_t) ((foff + off) & PAGE_MASK), size)) { bp->b_flags &= ~B_CACHE; } } /* * Set the valid bits in a page, taking care of the b_validoff, * b_validend fields which NFS uses to optimise small reads. Off is * the offset within the file and pageno is the page index within the buf. */ static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, int pageno, vm_page_t m) { struct vnode *vp = bp->b_vp; vm_ooffset_t soff, eoff; soff = off; eoff = off + min(PAGE_SIZE, bp->b_bufsize); if (vp->v_tag == VT_NFS && vp->v_type != VBLK) { vm_ooffset_t sv, ev; vm_page_set_invalid(m, (vm_offset_t) (soff & PAGE_MASK), (vm_offset_t) (eoff - soff)); off = off - pageno * PAGE_SIZE; sv = off + ((bp->b_validoff + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1)); ev = off + ((bp->b_validend + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1)); soff = qmax(sv, soff); eoff = qmin(ev, eoff); } if (eoff > soff) vm_page_set_validclean(m, (vm_offset_t) (soff & PAGE_MASK), (vm_offset_t) (eoff - soff)); } /* * This routine is called before a device strategy routine. * It is used to tell the VM system that paging I/O is in * progress, and treat the pages associated with the buffer * almost as being PG_BUSY. Also the object paging_in_progress * flag is handled to make sure that the object doesn't become * inconsistant. */ void vfs_busy_pages(struct buf * bp, int clear_modify) { int i, s; if (bp->b_flags & B_VMIO) { struct vnode *vp = bp->b_vp; vm_object_t obj = vp->v_object; vm_ooffset_t foff; foff = bp->b_offset; #ifdef DIAGNOSTIC if (bp->b_offset == NOOFFSET) panic("vfs_busy_pages: no buffer offset"); #endif vfs_setdirty(bp); retry: for (i = 0; i < bp->b_npages; i++) { vm_page_t m = bp->b_pages[i]; if (vm_page_sleep(m, "vbpage", NULL)) goto retry; } for (i = 0; i < bp->b_npages; i++, foff += PAGE_SIZE) { vm_page_t m = bp->b_pages[i]; vm_page_flag_clear(m, PG_ZERO); if ((bp->b_flags & B_CLUSTER) == 0) { vm_object_pip_add(obj, 1); vm_page_io_start(m); } vm_page_protect(m, VM_PROT_NONE); if (clear_modify) vfs_page_set_valid(bp, foff, i, m); else if (bp->b_bcount >= PAGE_SIZE) { if (m->valid && (bp->b_flags & B_CACHE) == 0) { bp->b_pages[i] = bogus_page; pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); } } } } } /* * Tell the VM system that the pages associated with this buffer * are clean. This is used for delayed writes where the data is * going to go to disk eventually without additional VM intevention. */ void vfs_clean_pages(struct buf * bp) { int i; if (bp->b_flags & B_VMIO) { struct vnode *vp = bp->b_vp; vm_ooffset_t foff; foff = bp->b_offset; #ifdef DIAGNOSTIC if (bp->b_offset == NOOFFSET) panic("vfs_clean_pages: no buffer offset"); #endif for (i = 0; i < bp->b_npages; i++, foff += PAGE_SIZE) { vm_page_t m = bp->b_pages[i]; vfs_page_set_valid(bp, foff, i, m); } } } void vfs_bio_clrbuf(struct buf *bp) { int i; if ((bp->b_flags & (B_VMIO | B_MALLOC)) == B_VMIO) { if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE)) { int mask; mask = 0; for(i=0;ib_bufsize;i+=DEV_BSIZE) mask |= (1 << (i/DEV_BSIZE)); if(((bp->b_pages[0]->flags & PG_ZERO) == 0) && (bp->b_pages[0]->valid != mask)) { bzero(bp->b_data, bp->b_bufsize); } bp->b_pages[0]->valid = mask; bp->b_resid = 0; return; } for(i=0;ib_npages;i++) { if( bp->b_pages[i]->valid == VM_PAGE_BITS_ALL) continue; if( bp->b_pages[i]->valid == 0) { if ((bp->b_pages[i]->flags & PG_ZERO) == 0) { bzero(bp->b_data + (i << PAGE_SHIFT), PAGE_SIZE); } } else { int j; for(j=0;jb_pages[i]->flags & PG_ZERO) == 0) && (bp->b_pages[i]->valid & (1<b_data + (i << PAGE_SHIFT) + j * DEV_BSIZE, DEV_BSIZE); } } bp->b_pages[i]->valid = VM_PAGE_BITS_ALL; vm_page_flag_clear(bp->b_pages[i], PG_ZERO); } bp->b_resid = 0; } else { clrbuf(bp); } } /* * vm_hold_load_pages and vm_hold_unload pages get pages into * a buffers address space. The pages are anonymous and are * not associated with a file object. */ void vm_hold_load_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) { vm_offset_t pg; vm_page_t p; int index; to = round_page(to); from = round_page(from); index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT; for (pg = from; pg < to; pg += PAGE_SIZE, index++) { tryagain: p = vm_page_alloc(kernel_object, ((pg - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), VM_ALLOC_NORMAL); if (!p) { vm_pageout_deficit += (to - from) >> PAGE_SHIFT; VM_WAIT; goto tryagain; } vm_page_wire(p); p->valid = VM_PAGE_BITS_ALL; vm_page_flag_clear(p, PG_ZERO); pmap_kenter(pg, VM_PAGE_TO_PHYS(p)); bp->b_pages[index] = p; vm_page_wakeup(p); } bp->b_npages = index; } void vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) { vm_offset_t pg; vm_page_t p; int index, newnpages; from = round_page(from); to = round_page(to); newnpages = index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT; for (pg = from; pg < to; pg += PAGE_SIZE, index++) { p = bp->b_pages[index]; if (p && (index < bp->b_npages)) { #if !defined(MAX_PERF) if (p->busy) { printf("vm_hold_free_pages: blkno: %d, lblkno: %d\n", bp->b_blkno, bp->b_lblkno); } #endif bp->b_pages[index] = NULL; pmap_kremove(pg); vm_page_busy(p); vm_page_unwire(p); vm_page_free(p); } } bp->b_npages = newnpages; } #include "opt_ddb.h" #ifdef DDB #include DB_SHOW_COMMAND(buffer, db_show_buffer) { /* get args */ struct buf *bp = (struct buf *)addr; if (!have_addr) { db_printf("usage: show buffer \n"); return; } db_printf("b_proc = %p,\nb_flags = 0x%b\n", (void *)bp->b_proc, (u_int)bp->b_flags, PRINT_BUF_FLAGS); db_printf("b_error = %d, b_bufsize = %ld, b_bcount = %ld, " "b_resid = %ld\nb_dev = 0x%x, b_data = %p, " "b_blkno = %d, b_pblkno = %d\n", bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, bp->b_dev, bp->b_data, bp->b_blkno, bp->b_pblkno); if (bp->b_npages) { int i; db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); for (i = 0; i < bp->b_npages; i++) { vm_page_t m; m = bp->b_pages[i]; db_printf("(%p, 0x%lx, 0x%lx)", (void *)m->object, (u_long)m->pindex, (u_long)VM_PAGE_TO_PHYS(m)); if ((i + 1) < bp->b_npages) db_printf(","); } db_printf("\n"); } } #endif /* DDB */