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33 * @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95
34 * $FreeBSD: src/sys/ufs/mfs/mfs_vfsops.c,v 1.81.2.3 2001/07/04 17:35:21 tegge Exp $
38 #include <sys/param.h>
39 #include <sys/systm.h>
41 #include <sys/device.h>
42 #include <sys/kernel.h>
45 #include <sys/mount.h>
46 #include <sys/signalvar.h>
47 #include <sys/signal2.h>
48 #include <sys/vnode.h>
49 #include <sys/malloc.h>
50 #include <sys/sysproto.h>
52 #include <sys/linker.h>
53 #include <sys/fcntl.h>
54 #include <sys/nlookup.h>
55 #include <sys/devfs.h>
58 #include <vm/vm_object.h>
59 #include <vm/vm_page.h>
60 #include <vm/vm_pager.h>
61 #include <vm/vnode_pager.h>
62 #include <vm/vm_extern.h>
65 #include <sys/thread2.h>
67 #include <vfs/ufs/quota.h>
68 #include <vfs/ufs/inode.h>
69 #include <vfs/ufs/ufsmount.h>
70 #include <vfs/ufs/ufs_extern.h>
71 #include <vfs/ufs/fs.h>
72 #include <vfs/ufs/ffs_extern.h>
75 #include "mfs_extern.h"
77 MALLOC_DEFINE(M_MFSNODE, "MFS node", "MFS vnode private part");
79 static int mfs_mount (struct mount *mp,
80 char *path, caddr_t data, struct ucred *td);
81 static int mfs_start (struct mount *mp, int flags);
82 static int mfs_statfs (struct mount *mp, struct statfs *sbp,
84 static int mfs_init (struct vfsconf *);
85 static void mfs_doio(struct bio *bio, struct mfsnode *mfsp);
89 d_strategy_t mfsstrategy;
91 static struct dev_ops mfs_ops = {
92 { "MFS", -1, D_DISK },
97 .d_strategy = mfsstrategy,
101 * mfs vfs operations.
103 static struct vfsops mfs_vfsops = {
104 .vfs_mount = mfs_mount,
105 .vfs_start = mfs_start,
106 .vfs_unmount = ffs_unmount,
107 .vfs_root = ufs_root,
108 .vfs_quotactl = ufs_quotactl,
109 .vfs_statfs = mfs_statfs,
110 .vfs_sync = ffs_sync,
111 .vfs_vget = ffs_vget,
112 .vfs_fhtovp = ffs_fhtovp,
113 .vfs_checkexp = ufs_check_export,
114 .vfs_vptofh = ffs_vptofh,
118 VFS_SET(mfs_vfsops, mfs, 0);
119 MODULE_VERSION(mfs, 1);
122 * We allow the underlying MFS block device to be opened and read.
125 mfsopen(struct dev_open_args *ap)
127 cdev_t dev = ap->a_head.a_dev;
130 if (ap->a_oflags & FWRITE)
139 mfsclose(struct dev_close_args *ap)
141 cdev_t dev = ap->a_head.a_dev;
142 struct mfsnode *mfsp;
144 if ((mfsp = dev->si_drv1) == NULL)
146 mfsp->mfs_active = 0;
147 wakeup((caddr_t)mfsp);
152 mfsstrategy(struct dev_strategy_args *ap)
154 cdev_t dev = ap->a_head.a_dev;
155 struct bio *bio = ap->a_bio;
156 struct buf *bp = bio->bio_buf;
157 off_t boff = bio->bio_offset;
158 off_t eoff = boff + bp->b_bcount;
159 struct mfsnode *mfsp;
161 if ((mfsp = dev->si_drv1) == NULL) {
167 if (eoff > mfsp->mfs_size) {
168 if (boff > mfsp->mfs_size || (bp->b_flags & B_BNOCLIP))
171 * Return EOF by completing the I/O with 0 bytes transfered.
172 * Set B_INVAL to indicate that any data in the buffer is not
175 if (boff == mfsp->mfs_size) {
176 bp->b_resid = bp->b_bcount;
177 bp->b_flags |= B_INVAL;
180 bp->b_bcount = mfsp->mfs_size - boff;
186 if (mfsp->mfs_td == curthread) {
189 bioq_insert_tail(&mfsp->bio_queue, bio);
190 wakeup((caddr_t)mfsp);
195 * Failure conditions on bio
198 bp->b_error = EINVAL;
200 bp->b_flags |= B_ERROR | B_INVAL;
209 * Called when mounting local physical media
213 * mp mount point structure
214 * path NULL (flag for root mount!!!)
217 * p process (user credentials check [statfs])
220 * mp mount point structure
221 * path path to mount point
222 * data pointer to argument struct in user space
223 * ndp mount point namei() return (used for
224 * credentials on reload), reused to look
226 * p process (user credentials check)
229 * !0 error number (errno.h)
234 * mount point is locked
236 * mount point is locked
239 * A NULL path can be used for a flag since the mount
240 * system call will fail with EFAULT in copyinstr in
241 * namei() if it is a genuine NULL from the user.
245 mfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
248 struct mfs_args args;
249 struct ufsmount *ump;
251 struct mfsnode *mfsp;
252 struct nlookupdata nd;
261 * Use NULL path to flag a root mount
266 * Mounting root file system
271 panic("mfs_mount: mount MFS as root: not configured!");
278 * Mounting non-root file system or updating a file system
282 /* copy in user arguments*/
283 error = copyin(data, (caddr_t)&args, sizeof (struct mfs_args));
288 * If updating, check whether changing from read-only to
289 * read/write; if there is no device name, that's all we do.
291 if (mp->mnt_flag & MNT_UPDATE) {
299 if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
301 if (mp->mnt_flag & MNT_FORCE)
303 error = ffs_flushfiles(mp, flags);
307 if (fs->fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
308 /* XXX reopen the device vnode read-write */
311 /* if not updating name...*/
312 if (args.fspec == 0) {
314 * Process export requests. Jumping to "success"
315 * will return the vfs_export() error code.
317 error = vfs_export(mp, &ump->um_export, &args.export);
321 /* XXX MFS does not support name updating*/
326 * Do the MALLOC before the make_dev since doing so afterward
327 * might cause a bogus v_data pointer to get dereferenced
328 * elsewhere if MALLOC should block.
330 mfsp = kmalloc(sizeof *mfsp, M_MFSNODE, M_WAITOK | M_ZERO);
332 minnum = (int)curproc->p_pid;
334 dev = make_dev(&mfs_ops, minnum, UID_ROOT, GID_WHEEL, 0600,
336 /* It is not clear that these will get initialized otherwise */
337 dev->si_bsize_phys = DEV_BSIZE;
338 dev->si_iosize_max = MAXPHYS;
340 mfsp->mfs_baseoff = args.base;
341 mfsp->mfs_size = args.size;
343 mfsp->mfs_td = curthread;
344 mfsp->mfs_active = 1;
345 bioq_init(&mfsp->bio_queue);
347 devfs_config(); /* sync devfs work */
348 ksnprintf(devname, sizeof(devname), "/dev/mfs%d", minnum);
349 nlookup_init(&nd, devname, UIO_SYSSPACE, 0);
351 error = nlookup(&nd);
353 devvp = nd.nl_nch.ncp->nc_vp;
356 error = vget(devvp, LK_SHARED);
365 * Our 'block' device must be backed by a VM object. Theoretically
366 * we could use the anonymous memory VM object supplied by userland,
367 * but it would be somewhat of a complex task to deal with it
368 * that way since it would result in I/O requests which supply
369 * the VM pages from our own object.
371 * vnode_pager_alloc() is typically called when a VM object is
372 * being referenced externally. We have to undo the refs for
373 * the self reference between vnode and object.
375 vnode_pager_setsize(devvp, args.size);
377 /* Save "mounted from" info for mount point (NULL pad)*/
378 copyinstr(args.fspec, /* device name*/
379 mp->mnt_stat.f_mntfromname, /* save area*/
380 MNAMELEN - 1, /* max size*/
381 &size); /* real size*/
382 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
383 /* vref is eaten by mount? */
385 error = ffs_mountfs(devvp, mp, M_MFSNODE);
387 mfsp->mfs_active = 0;
392 * Initialize FS stat information in mount struct; uses
393 * mp->mnt_stat.f_mntfromname.
395 * This code is common to root and non-root mounts
397 VFS_STATFS(mp, &mp->mnt_stat, cred);
400 * Mark VFS_START MPSAFE; this is to avoid accessing
401 * per-mount token after VFS_START exits
403 mp->mnt_kern_flag |= MNTK_ST_MPSAFE;
407 error_2: /* error with devvp held*/
410 error_1: /* no state to back out*/
413 destroy_dev(mfsp->mfs_dev);
414 mfsp->mfs_dev = NULL;
416 kfree(mfsp, M_MFSNODE);
424 * Used to grab the process and keep it in the kernel to service
425 * memory filesystem I/O requests.
427 * Loop servicing I/O requests.
428 * Copy the requested data into or out of the memory filesystem
433 mfs_start(struct mount *mp, int flags)
435 struct vnode *vp = VFSTOUFS(mp)->um_devvp;
436 struct mfsnode *mfsp = vp->v_rdev->si_drv1;
440 thread_t td = curthread;
443 * We must prevent the system from trying to swap
444 * out or kill ( when swap space is low, see vm/pageout.c ) the
445 * process. A deadlock can occur if the process is swapped out,
446 * and the system can loop trying to kill the unkillable ( while
447 * references exist ) MFS process when swap space is low.
454 while (mfsp->mfs_active) {
457 while ((bio = bioq_takefirst(&mfsp->bio_queue)) != NULL) {
468 * If a non-ignored signal is received, try to unmount.
469 * If that fails, clear the signal (it has been "processed"),
470 * otherwise we will loop here, as tsleep will always return
474 * Note that dounmount() may fail if work was queued after
475 * we slept. We have to jump hoops here to make sure that we
476 * process any buffers after the sleep, before we dounmount()
480 if (dounmount(mp, 0) != 0) {
481 KKASSERT(td->td_proc);
482 sig = CURSIG(td->td_lwp);
484 spin_lock(&td->td_lwp->lwp_spin);
485 lwp_delsig(td->td_lwp, sig);
486 spin_unlock(&td->td_lwp->lwp_spin);
490 else if (tsleep((caddr_t)mfsp, PCATCH, "mfsidl", 0))
491 gotsig++; /* try to unmount in next pass */
495 destroy_dev(mfsp->mfs_dev);
496 mfsp->mfs_dev = NULL;
498 kfree(mfsp, M_MFSNODE);
503 * Get file system statistics.
506 mfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
510 error = ffs_statfs(mp, sbp, cred);
511 sbp->f_type = mp->mnt_vfc->vfc_typenum;
516 * Memory based filesystem initialization.
519 mfs_init(struct vfsconf *vfsp)
525 * Memory file system I/O.
527 * Trivial on the HP since buffer has already been mapping into KVA space.
529 * Read and Write are handled with a simple copyin and copyout.
531 * We also partially support VOP_FREEBLKS(). We can't implement
532 * completely -- for example, on fragments or inode metadata, but we can
533 * implement it for page-aligned requests.
536 mfs_doio(struct bio *bio, struct mfsnode *mfsp)
538 struct buf *bp = bio->bio_buf;
539 caddr_t base = mfsp->mfs_baseoff + bio->bio_offset;
543 case BUF_CMD_FREEBLKS:
545 * Implement FREEBLKS, which allows the filesystem to tell
546 * a block device when blocks are no longer needed (like when
547 * a file is deleted). We use the hook to MADV_FREE the VM.
548 * This makes an MFS filesystem work as well or better then
549 * a sun-style swap-mounted filesystem.
551 bytes = bp->b_bcount;
553 if ((vm_offset_t)base & PAGE_MASK) {
554 int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK);
559 struct madvise_args uap;
563 bzero(&uap, sizeof(uap));
566 uap.behav = MADV_FREE;
574 * Read data from our 'memory' disk
576 bp->b_error = copyin(base, bp->b_data, bp->b_bcount);
580 * Write data to our 'memory' disk
582 bp->b_error = copyout(bp->b_data, base, bp->b_bcount);
585 panic("mfs: bad b_cmd %d", bp->b_cmd);
588 bp->b_flags |= B_ERROR;