/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved. */ /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ /* All Rights Reserved */ /* * University Copyright- Copyright (c) 1982, 1986, 1988 * The Regents of the University of California * All Rights Reserved * * University Acknowledgment- Portions of this document are derived from * software developed by the University of California, Berkeley, and its * contributors. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * dcfs - A filesystem for automatic decompressing of fiocompressed files * * This filesystem is a layered filesystem that sits on top of a normal * persistent filesystem and provides automatic decompression of files * that have been previously compressed and stored on the host file system. * This is a pseudo filesystem in that it does not persist data, rather it * intercepts file lookup requests on the host filesystem and provides * transparent decompression of those files. Currently the only supported * host filesystem is ufs. * * A file is compressed via a userland utility (currently cmd/boot/fiocompress) * and marked by fiocompress as a compressed file via a flag in the on-disk * inode (set via a ufs ioctl() - see `ufs_vnops.c`ufs_ioctl()`_FIO_COMPRESSED * ufs_lookup checks for this flag and if set, passes control to decompvp * a function defined in this (dcfs) filesystem. decomvp uncompresses the file * and returns a dcfs vnode to the VFS layer. * * dcfs is layered on top of ufs and passes requests involving persistence * to the underlying ufs filesystem. The compressed files currently cannot be * written to. */ /* * Define data structures within this file. */ #define DCSHFT 5 #define DCTABLESIZE 16 #if ((DCTABLESIZE & (DCTABLESIZE - 1)) == 0) #define DCHASH(vp) (((uintptr_t)(vp) >> DCSHFT) & (DCTABLESIZE - 1)) #else #define DCHASH(vp) (((uintptr_t)(vp) >> DCSHFT) % DTABLESIZEC) #endif #define DCLRUSIZE 16 #define DCCACHESIZE 4 #define rounddown(x, y) ((x) & ~((y) - 1)) struct dcnode *dctable[DCTABLESIZE]; struct dcnode *dclru; static int dclru_len; kmutex_t dctable_lock; dev_t dcdev; struct vfs dc_vfs; struct kmem_cache *dcnode_cache; struct kmem_cache *dcbuf_cache[DCCACHESIZE]; kmutex_t dccache_lock; static int dcinit(int, char *); static struct dcnode *dcnode_alloc(void); static void dcnode_free(struct dcnode *); static void dcnode_recycle(struct dcnode *); static void dcinsert(struct dcnode *); static void dcdelete(struct dcnode *); static struct dcnode *dcfind(struct vnode *); static void dclru_add(struct dcnode *); static void dclru_sub(struct dcnode *); /* * This is the loadable module wrapper. */ #include struct vfsops *dc_vfsops; static vfsdef_t vfw = { VFSDEF_VERSION, "dcfs", dcinit, VSW_ZMOUNT, NULL }; /* * Module linkage information for the kernel. */ extern struct mod_ops mod_fsops; static struct modlfs modlfs = { &mod_fsops, "compressed filesystem", &vfw }; static struct modlinkage modlinkage = { MODREV_1, (void *)&modlfs, NULL }; int _init() { return (mod_install(&modlinkage)); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } static int dc_open(struct vnode **, int, struct cred *, caller_context_t *); static int dc_close(struct vnode *, int, int, offset_t, struct cred *, caller_context_t *); static int dc_read(struct vnode *, struct uio *, int, struct cred *, struct caller_context *); static int dc_getattr(struct vnode *, struct vattr *, int, struct cred *, caller_context_t *); static int dc_setattr(struct vnode *, struct vattr *, int, struct cred *, struct caller_context *); static int dc_access(struct vnode *, int, int, struct cred *, caller_context_t *); static int dc_fsync(struct vnode *, int, struct cred *, caller_context_t *); static void dc_inactive(struct vnode *, struct cred *, caller_context_t *); static int dc_fid(struct vnode *, struct fid *, caller_context_t *); static int dc_seek(struct vnode *, offset_t, offset_t *, caller_context_t *); static int dc_frlock(struct vnode *, int, struct flock64 *, int, offset_t, struct flk_callback *, struct cred *, caller_context_t *); static int dc_getpage(struct vnode *, offset_t, size_t, uint_t *, struct page **, size_t, struct seg *, caddr_t, enum seg_rw, struct cred *, caller_context_t *); static int dc_putpage(struct vnode *, offset_t, size_t, int, struct cred *, caller_context_t *); static int dc_map(struct vnode *, offset_t, struct as *, caddr_t *, size_t, uchar_t, uchar_t, uint_t, struct cred *, caller_context_t *); static int dc_addmap(struct vnode *, offset_t, struct as *, caddr_t, size_t, uchar_t, uchar_t, uint_t, struct cred *, caller_context_t *); static int dc_delmap(struct vnode *, offset_t, struct as *, caddr_t, size_t, uint_t, uint_t, uint_t, struct cred *, caller_context_t *); struct vnodeops *dc_vnodeops; const fs_operation_def_t dc_vnodeops_template[] = { VOPNAME_OPEN, { .vop_open = dc_open }, VOPNAME_CLOSE, { .vop_close = dc_close }, VOPNAME_READ, { .vop_read = dc_read }, VOPNAME_GETATTR, { .vop_getattr = dc_getattr }, VOPNAME_SETATTR, { .vop_setattr = dc_setattr }, VOPNAME_ACCESS, { .vop_access = dc_access }, VOPNAME_FSYNC, { .vop_fsync = dc_fsync }, VOPNAME_INACTIVE, { .vop_inactive = dc_inactive }, VOPNAME_FID, { .vop_fid = dc_fid }, VOPNAME_SEEK, { .vop_seek = dc_seek }, VOPNAME_FRLOCK, { .vop_frlock = dc_frlock }, VOPNAME_GETPAGE, { .vop_getpage = dc_getpage }, VOPNAME_PUTPAGE, { .vop_putpage = dc_putpage }, VOPNAME_MAP, { .vop_map = dc_map }, VOPNAME_ADDMAP, { .vop_addmap = dc_addmap }, VOPNAME_DELMAP, { .vop_delmap = dc_delmap }, NULL, NULL }; /*ARGSUSED*/ static int dc_open(struct vnode **vpp, int flag, struct cred *cr, caller_context_t *ctp) { return (0); } /*ARGSUSED*/ static int dc_close(struct vnode *vp, int flag, int count, offset_t off, struct cred *cr, caller_context_t *ctp) { (void) cleanlocks(vp, ttoproc(curthread)->p_pid, 0); cleanshares(vp, ttoproc(curthread)->p_pid); return (0); } /*ARGSUSED*/ static int dc_read(struct vnode *vp, struct uio *uiop, int ioflag, struct cred *cr, struct caller_context *ct) { struct dcnode *dp = VTODC(vp); size_t rdsize = MAX(MAXBSIZE, dp->dc_hdr->ch_blksize); size_t fsize = dp->dc_hdr->ch_fsize; int error; /* * Loop through file with segmap, decompression will occur * in dc_getapage */ do { caddr_t base; size_t n; offset_t mapon; /* * read to end of block or file */ mapon = uiop->uio_loffset & (rdsize - 1); n = MIN(rdsize - mapon, uiop->uio_resid); n = MIN(n, fsize - uiop->uio_loffset); if (n == 0) return (0); /* at EOF */ base = segmap_getmapflt(segkmap, vp, uiop->uio_loffset, n, 1, S_READ); error = uiomove(base + mapon, n, UIO_READ, uiop); if (!error) { uint_t flags; if (n + mapon == rdsize || uiop->uio_loffset == fsize) flags = SM_DONTNEED; else flags = 0; error = segmap_release(segkmap, base, flags); } else (void) segmap_release(segkmap, base, 0); } while (!error && uiop->uio_resid); return (error); } static int dc_getattr(struct vnode *vp, struct vattr *vap, int flags, cred_t *cred, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct vnode *subvp = dp->dc_subvp; int error; error = VOP_GETATTR(subvp, vap, flags, cred, ctp); /* substitute uncompressed size */ vap->va_size = dp->dc_hdr->ch_fsize; return (error); } static int dc_setattr(struct vnode *vp, struct vattr *vap, int flags, cred_t *cred, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct vnode *subvp = dp->dc_subvp; return (VOP_SETATTR(subvp, vap, flags, cred, ctp)); } static int dc_access(struct vnode *vp, int mode, int flags, cred_t *cred, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct vnode *subvp = dp->dc_subvp; return (VOP_ACCESS(subvp, mode, flags, cred, ctp)); } /*ARGSUSED*/ static int dc_fsync(vnode_t *vp, int syncflag, cred_t *cred, caller_context_t *ctp) { return (0); } /*ARGSUSED*/ static void dc_inactive(struct vnode *vp, cred_t *cr, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); mutex_enter(&dctable_lock); mutex_enter(&vp->v_lock); ASSERT(vp->v_count >= 1); if (--vp->v_count != 0) { /* * Somebody accessed the dcnode before we got a chance to * remove it. They will remove it when they do a vn_rele. */ mutex_exit(&vp->v_lock); mutex_exit(&dctable_lock); return; } mutex_exit(&vp->v_lock); dcnode_free(dp); mutex_exit(&dctable_lock); } static int dc_fid(struct vnode *vp, struct fid *fidp, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct vnode *subvp = dp->dc_subvp; return (VOP_FID(subvp, fidp, ctp)); } static int dc_seek(struct vnode *vp, offset_t oof, offset_t *noffp, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct vnode *subvp = dp->dc_subvp; return (VOP_SEEK(subvp, oof, noffp, ctp)); } static int dc_frlock(struct vnode *vp, int cmd, struct flock64 *bfp, int flag, offset_t offset, struct flk_callback *flk_cbp, cred_t *cr, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); /* * If file is being mapped, disallow frlock. */ if (dp->dc_mapcnt > 0) return (EAGAIN); return (fs_frlock(vp, cmd, bfp, flag, offset, flk_cbp, cr, ctp)); } /*ARGSUSED*/ static int dc_getblock_miss(struct vnode *vp, offset_t off, size_t len, struct page **ppp, struct seg *seg, caddr_t addr, enum seg_rw rw, struct cred *cr) { struct dcnode *dp = VTODC(vp); struct comphdr *hdr = dp->dc_hdr; struct page *pp; struct buf *bp; caddr_t saddr; off_t cblkno; size_t rdoff, rdsize, dsize; long xlen; int error, zerr; ASSERT(len == hdr->ch_blksize); /* * Get destination pages and make them addressable */ pp = page_create_va(vp, off, len, PG_WAIT, seg, addr); bp = pageio_setup(pp, len, vp, B_READ); bp_mapin(bp); /* * read compressed data from subordinate vnode */ saddr = kmem_cache_alloc(dp->dc_bufcache, KM_SLEEP); cblkno = off / len; rdoff = hdr->ch_blkmap[cblkno]; rdsize = hdr->ch_blkmap[cblkno + 1] - rdoff; error = vn_rdwr(UIO_READ, dp->dc_subvp, saddr, rdsize, rdoff, UIO_SYSSPACE, 0, 0, cr, NULL); if (error) goto cleanup; /* * Uncompress */ dsize = len; zerr = z_uncompress(bp->b_un.b_addr, &dsize, saddr, dp->dc_zmax); if (zerr != Z_OK) { error = EIO; goto cleanup; } /* * Handle EOF */ xlen = hdr->ch_fsize - off; if (xlen < len) { bzero(bp->b_un.b_addr + xlen, len - xlen); if (dsize != xlen) error = EIO; } else if (dsize != len) error = EIO; /* * Clean up */ cleanup: kmem_cache_free(dp->dc_bufcache, saddr); pageio_done(bp); *ppp = pp; return (error); } static int dc_getblock(struct vnode *vp, offset_t off, size_t len, struct page **ppp, struct seg *seg, caddr_t addr, enum seg_rw rw, struct cred *cr) { struct page *pp, *plist = NULL; offset_t pgoff; int rdblk; /* * pvn_read_kluster() doesn't quite do what we want, since it * thinks sub block reads are ok. Here we always decompress * a full block. */ /* * Check page cache */ rdblk = 0; for (pgoff = off; pgoff < off + len; pgoff += PAGESIZE) { pp = page_lookup(vp, pgoff, SE_EXCL); if (pp == NULL) { rdblk = 1; break; } page_io_lock(pp); page_add(&plist, pp); plist = plist->p_next; } if (!rdblk) { *ppp = plist; return (0); /* all pages in cache */ } /* * Undo any locks so getblock_miss has an open field */ if (plist != NULL) pvn_io_done(plist); return (dc_getblock_miss(vp, off, len, ppp, seg, addr, rw, cr)); } /*ARGSUSED10*/ static int dc_getpage(struct vnode *vp, offset_t off, size_t len, uint_t *protp, struct page *pl[], size_t plsz, struct seg *seg, caddr_t addr, enum seg_rw rw, struct cred *cr, caller_context_t *ctp) { struct dcnode *dp = VTODC(vp); struct comphdr *hdr = dp->dc_hdr; struct page *pp, *plist = NULL; caddr_t vp_baddr; offset_t vp_boff, vp_bend; size_t bsize = hdr->ch_blksize; int nblks, error; /* does not support write */ if (rw == S_WRITE) { panic("write attempt on compressed file"); /*NOTREACHED*/ } if (protp) *protp = PROT_ALL; /* * We don't support asynchronous operation at the moment, so * just pretend we did it. If the pages are ever actually * needed, they'll get brought in then. */ if (pl == NULL) return (0); /* * Calc block start and end offsets */ vp_boff = rounddown(off, bsize); vp_bend = roundup(off + len, bsize); vp_baddr = (caddr_t)rounddown((uintptr_t)addr, bsize); nblks = (vp_bend - vp_boff) / bsize; while (nblks--) { error = dc_getblock(vp, vp_boff, bsize, &pp, seg, vp_baddr, rw, cr); page_list_concat(&plist, &pp); vp_boff += bsize; vp_baddr += bsize; } if (!error) pvn_plist_init(plist, pl, plsz, off, len, rw); else pvn_read_done(plist, B_ERROR); return (error); } /* * This function should never be called. We need to have it to pass * it as an argument to other functions. */ /*ARGSUSED*/ static int dc_putapage(struct vnode *vp, struct page *pp, u_offset_t *offp, size_t *lenp, int flags, struct cred *cr) { /* should never happen */ cmn_err(CE_PANIC, "dcfs: dc_putapage: dirty page"); /*NOTREACHED*/ return (0); } /* * The only flags we support are B_INVAL, B_FREE and B_DONTNEED. * B_INVAL is set by: * * 1) the MC_SYNC command of memcntl(2) to support the MS_INVALIDATE flag. * 2) the MC_ADVISE command of memcntl(2) with the MADV_DONTNEED advice * which translates to an MC_SYNC with the MS_INVALIDATE flag. * * The B_FREE (as well as the B_DONTNEED) flag is set when the * MADV_SEQUENTIAL advice has been used. VOP_PUTPAGE is invoked * from SEGVN to release pages behind a pagefault. */ /*ARGSUSED5*/ static int dc_putpage(struct vnode *vp, offset_t off, size_t len, int flags, struct cred *cr, caller_context_t *ctp) { int error = 0; if (vp->v_count == 0) { panic("dcfs_putpage: bad v_count"); /*NOTREACHED*/ } if (vp->v_flag & VNOMAP) return (ENOSYS); if (!vn_has_cached_data(vp)) /* no pages mapped */ return (0); if (len == 0) /* from 'off' to EOF */ error = pvn_vplist_dirty(vp, off, dc_putapage, flags, cr); else { offset_t io_off; se_t se = (flags & (B_INVAL | B_FREE)) ? SE_EXCL : SE_SHARED; for (io_off = off; io_off < off + len; io_off += PAGESIZE) { page_t *pp; /* * We insist on getting the page only if we are * about to invalidate, free or write it and * the B_ASYNC flag is not set. */ if ((flags & B_INVAL) || ((flags & B_ASYNC) == 0)) pp = page_lookup(vp, io_off, se); else pp = page_lookup_nowait(vp, io_off, se); if (pp == NULL) continue; /* * Normally pvn_getdirty() should return 0, which * impies that it has done the job for us. * The shouldn't-happen scenario is when it returns 1. * This means that the page has been modified and * needs to be put back. * Since we can't write to a dcfs compressed file, * we fake a failed I/O and force pvn_write_done() * to destroy the page. */ if (pvn_getdirty(pp, flags) == 1) { cmn_err(CE_NOTE, "dc_putpage: dirty page"); pvn_write_done(pp, flags | B_ERROR | B_WRITE | B_INVAL | B_FORCE); } } } return (error); } static int dc_map(struct vnode *vp, offset_t off, struct as *as, caddr_t *addrp, size_t len, uchar_t prot, uchar_t maxprot, uint_t flags, struct cred *cred, caller_context_t *ctp) { struct vattr vattr; struct segvn_crargs vn_a; int error; if (vp->v_flag & VNOMAP) return (ENOSYS); if (off < (offset_t)0 || (offset_t)(off + len) < (offset_t)0) return (ENXIO); /* * If file is being locked, disallow mapping. */ if (error = VOP_GETATTR(VTODC(vp)->dc_subvp, &vattr, 0, cred, ctp)) return (error); if (vn_has_mandatory_locks(vp, vattr.va_mode)) return (EAGAIN); as_rangelock(as); if ((flags & MAP_FIXED) == 0) { map_addr(addrp, len, off, 1, flags); if (*addrp == NULL) { as_rangeunlock(as); return (ENOMEM); } } else { /* * User specified address - blow away any previous mappings */ (void) as_unmap(as, *addrp, len); } vn_a.vp = vp; vn_a.offset = off; vn_a.type = flags & MAP_TYPE; vn_a.prot = prot; vn_a.maxprot = maxprot; vn_a.flags = flags & ~MAP_TYPE; vn_a.cred = cred; vn_a.amp = NULL; vn_a.szc = 0; vn_a.lgrp_mem_policy_flags = 0; error = as_map(as, *addrp, len, segvn_create, &vn_a); as_rangeunlock(as); return (error); } /*ARGSUSED*/ static int dc_addmap(struct vnode *vp, offset_t off, struct as *as, caddr_t addr, size_t len, uchar_t prot, uchar_t maxprot, uint_t flags, struct cred *cr, caller_context_t *ctp) { struct dcnode *dp; if (vp->v_flag & VNOMAP) return (ENOSYS); dp = VTODC(vp); mutex_enter(&dp->dc_lock); dp->dc_mapcnt += btopr(len); mutex_exit(&dp->dc_lock); return (0); } /*ARGSUSED*/ static int dc_delmap(struct vnode *vp, offset_t off, struct as *as, caddr_t addr, size_t len, uint_t prot, uint_t maxprot, uint_t flags, struct cred *cr, caller_context_t *ctp) { struct dcnode *dp; if (vp->v_flag & VNOMAP) return (ENOSYS); dp = VTODC(vp); mutex_enter(&dp->dc_lock); dp->dc_mapcnt -= btopr(len); ASSERT(dp->dc_mapcnt >= 0); mutex_exit(&dp->dc_lock); return (0); } /* * Constructor/destructor routines for dcnodes */ /*ARGSUSED1*/ static int dcnode_constructor(void *buf, void *cdrarg, int kmflags) { struct dcnode *dp = buf; struct vnode *vp; vp = dp->dc_vp = vn_alloc(kmflags); if (vp == NULL) { return (-1); } vp->v_data = dp; vp->v_type = VREG; vp->v_flag = VNOSWAP; vp->v_vfsp = &dc_vfs; vn_setops(vp, dc_vnodeops); vn_exists(vp); mutex_init(&dp->dc_lock, NULL, MUTEX_DEFAULT, NULL); dp->dc_mapcnt = 0; dp->dc_lrunext = dp->dc_lruprev = NULL; dp->dc_hdr = NULL; dp->dc_subvp = NULL; return (0); } /*ARGSUSED*/ static void dcnode_destructor(void *buf, void *cdrarg) { struct dcnode *dp = buf; struct vnode *vp = DCTOV(dp); mutex_destroy(&dp->dc_lock); VERIFY(dp->dc_hdr == NULL); VERIFY(dp->dc_subvp == NULL); vn_invalid(vp); vn_free(vp); } static struct dcnode * dcnode_alloc(void) { struct dcnode *dp; /* * If the free list is above DCLRUSIZE * re-use one from it */ mutex_enter(&dctable_lock); if (dclru_len < DCLRUSIZE) { mutex_exit(&dctable_lock); dp = kmem_cache_alloc(dcnode_cache, KM_SLEEP); } else { ASSERT(dclru != NULL); dp = dclru; dclru_sub(dp); dcdelete(dp); mutex_exit(&dctable_lock); dcnode_recycle(dp); } return (dp); } static void dcnode_free(struct dcnode *dp) { struct vnode *vp = DCTOV(dp); ASSERT(MUTEX_HELD(&dctable_lock)); /* * If no cached pages, no need to put it on lru */ if (!vn_has_cached_data(vp)) { dcdelete(dp); dcnode_recycle(dp); kmem_cache_free(dcnode_cache, dp); return; } /* * Add to lru, if it's over the limit, free from head */ dclru_add(dp); if (dclru_len > DCLRUSIZE) { dp = dclru; dclru_sub(dp); dcdelete(dp); dcnode_recycle(dp); kmem_cache_free(dcnode_cache, dp); } } static void dcnode_recycle(struct dcnode *dp) { struct vnode *vp; vp = DCTOV(dp); VN_RELE(dp->dc_subvp); dp->dc_subvp = NULL; (void) pvn_vplist_dirty(vp, 0, dc_putapage, B_INVAL, NULL); kmem_free(dp->dc_hdr, dp->dc_hdrsize); dp->dc_hdr = NULL; dp->dc_hdrsize = dp->dc_zmax = 0; dp->dc_bufcache = NULL; dp->dc_mapcnt = 0; vn_reinit(vp); vp->v_type = VREG; vp->v_flag = VNOSWAP; vp->v_vfsp = &dc_vfs; } static int dcinit(int fstype, char *name) { static const fs_operation_def_t dc_vfsops_template[] = { NULL, NULL }; int error; major_t dev; error = vfs_setfsops(fstype, dc_vfsops_template, &dc_vfsops); if (error) { cmn_err(CE_WARN, "dcinit: bad vfs ops template"); return (error); } VFS_INIT(&dc_vfs, dc_vfsops, NULL); dc_vfs.vfs_flag = VFS_RDONLY; dc_vfs.vfs_fstype = fstype; if ((dev = getudev()) == (major_t)-1) dev = 0; dcdev = makedevice(dev, 0); dc_vfs.vfs_dev = dcdev; error = vn_make_ops(name, dc_vnodeops_template, &dc_vnodeops); if (error != 0) { (void) vfs_freevfsops_by_type(fstype); cmn_err(CE_WARN, "dcinit: bad vnode ops template"); return (error); } mutex_init(&dctable_lock, NULL, MUTEX_DEFAULT, NULL); mutex_init(&dccache_lock, NULL, MUTEX_DEFAULT, NULL); dcnode_cache = kmem_cache_create("dcnode_cache", sizeof (struct dcnode), 0, dcnode_constructor, dcnode_destructor, NULL, NULL, NULL, 0); return (0); } /* * Return shadow vnode with the given vp as its subordinate */ struct vnode * decompvp(struct vnode *vp, cred_t *cred, caller_context_t *ctp) { struct dcnode *dp, *ndp; struct comphdr thdr, *hdr; struct kmem_cache **cpp; struct vattr vattr; size_t hdrsize, bsize; int error; /* * See if we have an existing shadow * If none, we have to manufacture one */ mutex_enter(&dctable_lock); dp = dcfind(vp); mutex_exit(&dctable_lock); if (dp != NULL) return (DCTOV(dp)); /* * Make sure it's a valid compressed file */ hdr = &thdr; error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, sizeof (struct comphdr), 0, UIO_SYSSPACE, 0, 0, cred, NULL); if (error || hdr->ch_magic != CH_MAGIC_ZLIB || hdr->ch_version != CH_VERSION || hdr->ch_algorithm != CH_ALG_ZLIB || hdr->ch_fsize == 0 || hdr->ch_blksize < PAGESIZE || hdr->ch_blksize > ptob(DCCACHESIZE) || (hdr->ch_blksize & (hdr->ch_blksize - 1)) != 0) return (NULL); /* get underlying file size */ if (VOP_GETATTR(vp, &vattr, 0, cred, ctp) != 0) return (NULL); /* * Re-read entire header */ hdrsize = hdr->ch_blkmap[0] + sizeof (uint64_t); hdr = kmem_alloc(hdrsize, KM_SLEEP); error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, hdrsize, 0, UIO_SYSSPACE, 0, 0, cred, NULL); if (error) { kmem_free(hdr, hdrsize); return (NULL); } /* * add extra blkmap entry to make dc_getblock()'s * life easier */ bsize = hdr->ch_blksize; hdr->ch_blkmap[((hdr->ch_fsize-1) / bsize) + 1] = vattr.va_size; ndp = dcnode_alloc(); ndp->dc_subvp = vp; VN_HOLD(vp); ndp->dc_hdr = hdr; ndp->dc_hdrsize = hdrsize; /* * Allocate kmem cache if none there already */ ndp->dc_zmax = ZMAXBUF(bsize); cpp = &dcbuf_cache[btop(bsize)]; mutex_enter(&dccache_lock); if (*cpp == NULL) *cpp = kmem_cache_create("dcbuf_cache", ndp->dc_zmax, 0, NULL, NULL, NULL, NULL, NULL, 0); mutex_exit(&dccache_lock); ndp->dc_bufcache = *cpp; /* * Recheck table in case someone else created shadow * while we were blocked above. */ mutex_enter(&dctable_lock); dp = dcfind(vp); if (dp != NULL) { mutex_exit(&dctable_lock); dcnode_recycle(ndp); kmem_cache_free(dcnode_cache, ndp); return (DCTOV(dp)); } dcinsert(ndp); mutex_exit(&dctable_lock); return (DCTOV(ndp)); } /* * dcnode lookup table * These routines maintain a table of dcnodes hashed by their * subordinate vnode so that they can be found if they already * exist in the vnode cache */ /* * Put a dcnode in the table. */ static void dcinsert(struct dcnode *newdp) { int idx = DCHASH(newdp->dc_subvp); ASSERT(MUTEX_HELD(&dctable_lock)); newdp->dc_hash = dctable[idx]; dctable[idx] = newdp; } /* * Remove a dcnode from the hash table. */ void dcdelete(struct dcnode *deldp) { int idx = DCHASH(deldp->dc_subvp); struct dcnode *dp, *prevdp; ASSERT(MUTEX_HELD(&dctable_lock)); dp = dctable[idx]; if (dp == deldp) dctable[idx] = dp->dc_hash; else { for (prevdp = dp, dp = dp->dc_hash; dp != NULL; prevdp = dp, dp = dp->dc_hash) { if (dp == deldp) { prevdp->dc_hash = dp->dc_hash; break; } } } ASSERT(dp != NULL); } /* * Find a shadow vnode in the dctable hash list. */ static struct dcnode * dcfind(struct vnode *vp) { struct dcnode *dp; ASSERT(MUTEX_HELD(&dctable_lock)); for (dp = dctable[DCHASH(vp)]; dp != NULL; dp = dp->dc_hash) if (dp->dc_subvp == vp) { VN_HOLD(DCTOV(dp)); if (dp->dc_lrunext) dclru_sub(dp); return (dp); } return (NULL); } #ifdef DEBUG static int dclru_count(void) { struct dcnode *dp; int i = 0; if (dclru == NULL) return (0); for (dp = dclru; dp->dc_lrunext != dclru; dp = dp->dc_lrunext) i++; return (i + 1); } #endif static void dclru_add(struct dcnode *dp) { /* * Add to dclru as double-link chain */ ASSERT(MUTEX_HELD(&dctable_lock)); if (dclru == NULL) { dclru = dp; dp->dc_lruprev = dp->dc_lrunext = dp; } else { struct dcnode *last = dclru->dc_lruprev; dclru->dc_lruprev = dp; last->dc_lrunext = dp; dp->dc_lruprev = last; dp->dc_lrunext = dclru; } dclru_len++; ASSERT(dclru_len == dclru_count()); } static void dclru_sub(struct dcnode *dp) { ASSERT(MUTEX_HELD(&dctable_lock)); dp->dc_lrunext->dc_lruprev = dp->dc_lruprev; dp->dc_lruprev->dc_lrunext = dp->dc_lrunext; if (dp == dclru) dclru = dp->dc_lrunext == dp ? NULL : dp->dc_lrunext; dp->dc_lrunext = dp->dc_lruprev = NULL; dclru_len--; ASSERT(dclru_len == dclru_count()); }