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29 * @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95
30 * $FreeBSD: src/sys/ufs/mfs/mfs_vfsops.c,v 1.81.2.3 2001/07/04 17:35:21 tegge Exp $
34 #include <sys/param.h>
35 #include <sys/systm.h>
37 #include <sys/device.h>
38 #include <sys/kernel.h>
41 #include <sys/mount.h>
42 #include <sys/signalvar.h>
43 #include <sys/signal2.h>
44 #include <sys/spinlock2.h>
45 #include <sys/vnode.h>
46 #include <sys/malloc.h>
47 #include <sys/sysproto.h>
49 #include <sys/linker.h>
50 #include <sys/fcntl.h>
51 #include <sys/nlookup.h>
52 #include <sys/devfs.h>
55 #include <vm/vm_object.h>
56 #include <vm/vm_page.h>
57 #include <vm/vm_pager.h>
58 #include <vm/vnode_pager.h>
59 #include <vm/vm_extern.h>
62 #include <sys/thread2.h>
64 #include <vfs/ufs/quota.h>
65 #include <vfs/ufs/inode.h>
66 #include <vfs/ufs/ufsmount.h>
67 #include <vfs/ufs/ufs_extern.h>
68 #include <vfs/ufs/fs.h>
69 #include <vfs/ufs/ffs_extern.h>
72 #include "mfs_extern.h"
74 MALLOC_DEFINE(M_MFSNODE, "MFS node", "MFS vnode private part");
76 static int mfs_mount (struct mount *mp,
77 char *path, caddr_t data, struct ucred *td);
78 static int mfs_start (struct mount *mp, int flags);
79 static int mfs_statfs (struct mount *mp, struct statfs *sbp,
81 static int mfs_init (struct vfsconf *);
82 static void mfs_doio(struct bio *bio, struct mfsnode *mfsp);
86 d_strategy_t mfsstrategy;
88 static struct dev_ops mfs_ops = {
89 { "MFS", -1, D_DISK | D_NOEMERGPGR },
94 .d_strategy = mfsstrategy,
100 static struct vfsops mfs_vfsops = {
101 .vfs_mount = mfs_mount,
102 .vfs_start = mfs_start,
103 .vfs_unmount = ffs_unmount,
104 .vfs_root = ufs_root,
105 .vfs_quotactl = ufs_quotactl,
106 .vfs_statfs = mfs_statfs,
107 .vfs_sync = ffs_sync,
108 .vfs_vget = ffs_vget,
109 .vfs_fhtovp = ffs_fhtovp,
110 .vfs_checkexp = ufs_check_export,
111 .vfs_vptofh = ffs_vptofh,
115 VFS_SET(mfs_vfsops, mfs, 0);
116 MODULE_VERSION(mfs, 1);
119 * We allow the underlying MFS block device to be opened and read.
122 mfsopen(struct dev_open_args *ap)
124 cdev_t dev = ap->a_head.a_dev;
127 if (ap->a_oflags & FWRITE)
136 mfsclose(struct dev_close_args *ap)
138 cdev_t dev = ap->a_head.a_dev;
139 struct mfsnode *mfsp;
141 if ((mfsp = dev->si_drv1) == NULL)
143 mfsp->mfs_active = 0;
144 wakeup((caddr_t)mfsp);
149 mfsstrategy(struct dev_strategy_args *ap)
151 cdev_t dev = ap->a_head.a_dev;
152 struct bio *bio = ap->a_bio;
153 struct buf *bp = bio->bio_buf;
154 off_t boff = bio->bio_offset;
155 off_t eoff = boff + bp->b_bcount;
156 struct mfsnode *mfsp;
158 if ((mfsp = dev->si_drv1) == NULL) {
164 if (eoff > mfsp->mfs_size) {
165 if (boff > mfsp->mfs_size || (bp->b_flags & B_BNOCLIP))
168 * Return EOF by completing the I/O with 0 bytes transfered.
169 * Set B_INVAL to indicate that any data in the buffer is not
172 if (boff == mfsp->mfs_size) {
173 bp->b_resid = bp->b_bcount;
174 bp->b_flags |= B_INVAL;
177 bp->b_bcount = mfsp->mfs_size - boff;
183 if (mfsp->mfs_td == curthread) {
186 bioq_insert_tail(&mfsp->bio_queue, bio);
187 wakeup((caddr_t)mfsp);
192 * Failure conditions on bio
195 bp->b_error = EINVAL;
197 bp->b_flags |= B_ERROR | B_INVAL;
206 * Called when mounting local physical media
210 * mp mount point structure
211 * path NULL (flag for root mount!!!)
214 * p process (user credentials check [statfs])
217 * mp mount point structure
218 * path path to mount point
219 * data pointer to argument struct in user space
220 * ndp mount point namei() return (used for
221 * credentials on reload), reused to look
223 * p process (user credentials check)
226 * !0 error number (errno.h)
231 * mount point is locked
233 * mount point is locked
236 * A NULL path can be used for a flag since the mount
237 * system call will fail with EFAULT in copyinstr in
238 * namei() if it is a genuine NULL from the user.
242 mfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
245 struct mfs_args args;
246 struct ufsmount *ump;
248 struct mfsnode *mfsp;
249 struct nlookupdata nd;
258 * Use NULL path to flag a root mount
263 * Mounting root file system
268 panic("mfs_mount: mount MFS as root: not configured!");
275 * Mounting non-root file system or updating a file system
279 /* copy in user arguments*/
280 error = copyin(data, (caddr_t)&args, sizeof (struct mfs_args));
285 * If updating, check whether changing from read-only to
286 * read/write; if there is no device name, that's all we do.
288 if (mp->mnt_flag & MNT_UPDATE) {
296 if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
298 if (mp->mnt_flag & MNT_FORCE)
300 error = ffs_flushfiles(mp, flags);
304 if (fs->fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
305 /* XXX reopen the device vnode read-write */
308 /* if not updating name...*/
309 if (args.fspec == 0) {
311 * Process export requests. Jumping to "success"
312 * will return the vfs_export() error code.
314 error = vfs_export(mp, &ump->um_export, &args.export);
318 /* XXX MFS does not support name updating*/
323 * Do the MALLOC before the make_dev since doing so afterward
324 * might cause a bogus v_data pointer to get dereferenced
325 * elsewhere if MALLOC should block.
327 mfsp = kmalloc(sizeof *mfsp, M_MFSNODE, M_WAITOK | M_ZERO);
329 minnum = (int)curproc->p_pid;
331 dev = make_dev(&mfs_ops, minnum, UID_ROOT, GID_WHEEL, 0600,
333 /* It is not clear that these will get initialized otherwise */
334 dev->si_bsize_phys = DEV_BSIZE;
335 dev->si_iosize_max = MAXPHYS;
337 mfsp->mfs_baseoff = args.base;
338 mfsp->mfs_size = args.size;
340 mfsp->mfs_td = curthread;
341 mfsp->mfs_active = 1;
342 bioq_init(&mfsp->bio_queue);
344 devfs_config(); /* sync devfs work */
345 ksnprintf(devname, sizeof(devname), "/dev/mfs%d", minnum);
346 nlookup_init(&nd, devname, UIO_SYSSPACE, 0);
348 error = nlookup(&nd);
350 devvp = nd.nl_nch.ncp->nc_vp;
353 error = vget(devvp, LK_SHARED);
362 * Our 'block' device must be backed by a VM object. Theoretically
363 * we could use the anonymous memory VM object supplied by userland,
364 * but it would be somewhat of a complex task to deal with it
365 * that way since it would result in I/O requests which supply
366 * the VM pages from our own object.
368 * vnode_pager_alloc() is typically called when a VM object is
369 * being referenced externally. We have to undo the refs for
370 * the self reference between vnode and object.
372 vnode_pager_setsize(devvp, args.size);
374 /* Save "mounted from" info for mount point (NULL pad)*/
375 copyinstr(args.fspec, /* device name*/
376 mp->mnt_stat.f_mntfromname, /* save area*/
377 MNAMELEN - 1, /* max size*/
378 &size); /* real size*/
379 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
380 /* vref is eaten by mount? */
382 error = ffs_mountfs(devvp, mp, M_MFSNODE);
384 mfsp->mfs_active = 0;
389 * Initialize FS stat information in mount struct; uses
390 * mp->mnt_stat.f_mntfromname.
392 * This code is common to root and non-root mounts
394 VFS_STATFS(mp, &mp->mnt_stat, cred);
397 * Mark VFS_START MPSAFE; this is to avoid accessing
398 * per-mount token after VFS_START exits
400 mp->mnt_kern_flag |= MNTK_ST_MPSAFE;
404 error_2: /* error with devvp held*/
407 error_1: /* no state to back out*/
410 destroy_dev(mfsp->mfs_dev);
411 mfsp->mfs_dev = NULL;
413 kfree(mfsp, M_MFSNODE);
421 * Used to grab the process and keep it in the kernel to service
422 * memory filesystem I/O requests.
424 * Loop servicing I/O requests.
425 * Copy the requested data into or out of the memory filesystem
430 mfs_start(struct mount *mp, int flags)
432 struct vnode *vp = VFSTOUFS(mp)->um_devvp;
433 struct mfsnode *mfsp = vp->v_rdev->si_drv1;
437 thread_t td = curthread;
440 * We must prevent the system from trying to swap
441 * out or kill ( when swap space is low, see vm/pageout.c ) the
442 * process. A deadlock can occur if the process is swapped out,
443 * and the system can loop trying to kill the unkillable ( while
444 * references exist ) MFS process when swap space is low.
451 while (mfsp->mfs_active) {
454 while ((bio = bioq_takefirst(&mfsp->bio_queue)) != NULL) {
465 * If a non-ignored signal is received, try to unmount.
466 * If that fails, clear the signal (it has been "processed"),
467 * otherwise we will loop here, as tsleep will always return
471 * Note that dounmount() may fail if work was queued after
472 * we slept. We have to jump hoops here to make sure that we
473 * process any buffers after the sleep, before we dounmount()
477 if (dounmount(mp, 0, 0) != 0) {
478 KKASSERT(td->td_proc);
479 lwkt_gettoken(&td->td_proc->p_token);
480 sig = CURSIG(td->td_lwp);
482 spin_lock(&td->td_lwp->lwp_spin);
483 lwp_delsig(td->td_lwp, sig, 1);
484 spin_unlock(&td->td_lwp->lwp_spin);
486 lwkt_reltoken(&td->td_proc->p_token);
489 else if (tsleep((caddr_t)mfsp, PCATCH, "mfsidl", 0))
490 gotsig++; /* try to unmount in next pass */
494 destroy_dev(mfsp->mfs_dev);
495 mfsp->mfs_dev = NULL;
497 kfree(mfsp, M_MFSNODE);
502 * Get file system statistics.
505 mfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
509 error = ffs_statfs(mp, sbp, cred);
510 sbp->f_type = mp->mnt_vfc->vfc_typenum;
515 * Memory based filesystem initialization.
518 mfs_init(struct vfsconf *vfsp)
524 * Memory file system I/O.
526 * Trivial on the HP since buffer has already been mapping into KVA space.
528 * Read and Write are handled with a simple copyin and copyout.
530 * We also partially support VOP_FREEBLKS(). We can't implement
531 * completely -- for example, on fragments or inode metadata, but we can
532 * implement it for page-aligned requests.
535 mfs_doio(struct bio *bio, struct mfsnode *mfsp)
537 struct buf *bp = bio->bio_buf;
538 caddr_t base = mfsp->mfs_baseoff + bio->bio_offset;
542 case BUF_CMD_FREEBLKS:
544 * Implement FREEBLKS, which allows the filesystem to tell
545 * a block device when blocks are no longer needed (like when
546 * a file is deleted). We use the hook to MADV_FREE the VM.
547 * This makes an MFS filesystem work as well or better then
548 * a sun-style swap-mounted filesystem.
550 bytes = bp->b_bcount;
552 if ((vm_offset_t)base & PAGE_MASK) {
553 int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK);
558 struct madvise_args uap;
562 bzero(&uap, sizeof(uap));
565 uap.behav = MADV_FREE;
573 * Read data from our 'memory' disk
575 bp->b_error = copyin(base, bp->b_data, bp->b_bcount);
579 * Write data to our 'memory' disk
581 bp->b_error = copyout(bp->b_data, base, bp->b_bcount);
584 panic("mfs: bad b_cmd %d", bp->b_cmd);
587 bp->b_flags |= B_ERROR;