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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 $
35 * $DragonFly: src/sys/vfs/mfs/mfs_vfsops.c,v 1.41 2008/07/26 22:31:54 mneumann Exp $
39 #include <sys/param.h>
40 #include <sys/systm.h>
42 #include <sys/device.h>
43 #include <sys/kernel.h>
46 #include <sys/mount.h>
47 #include <sys/signalvar.h>
48 #include <sys/signal2.h>
49 #include <sys/vnode.h>
50 #include <sys/malloc.h>
51 #include <sys/sysproto.h>
53 #include <sys/linker.h>
54 #include <sys/fcntl.h>
55 #include <sys/nlookup.h>
56 #include <sys/devfs.h>
59 #include <vm/vm_object.h>
60 #include <vm/vm_page.h>
61 #include <vm/vm_pager.h>
62 #include <vm/vnode_pager.h>
63 #include <vm/vm_extern.h>
66 #include <sys/thread2.h>
68 #include <vfs/ufs/quota.h>
69 #include <vfs/ufs/inode.h>
70 #include <vfs/ufs/ufsmount.h>
71 #include <vfs/ufs/ufs_extern.h>
72 #include <vfs/ufs/fs.h>
73 #include <vfs/ufs/ffs_extern.h>
76 #include "mfs_extern.h"
78 MALLOC_DEFINE(M_MFSNODE, "MFS node", "MFS vnode private part");
80 static int mfs_mount (struct mount *mp,
81 char *path, caddr_t data, struct ucred *td);
82 static int mfs_start (struct mount *mp, int flags);
83 static int mfs_statfs (struct mount *mp, struct statfs *sbp,
85 static int mfs_init (struct vfsconf *);
86 static void mfs_doio(struct bio *bio, struct mfsnode *mfsp);
90 d_strategy_t mfsstrategy;
92 static struct dev_ops mfs_ops = {
93 { "MFS", -1, D_DISK },
98 .d_strategy = mfsstrategy,
102 * mfs vfs operations.
104 static struct vfsops mfs_vfsops = {
105 .vfs_mount = mfs_mount,
106 .vfs_start = mfs_start,
107 .vfs_unmount = ffs_unmount,
108 .vfs_root = ufs_root,
109 .vfs_quotactl = ufs_quotactl,
110 .vfs_statfs = mfs_statfs,
111 .vfs_sync = ffs_sync,
112 .vfs_vget = ffs_vget,
113 .vfs_fhtovp = ffs_fhtovp,
114 .vfs_checkexp = ufs_check_export,
115 .vfs_vptofh = ffs_vptofh,
119 VFS_SET(mfs_vfsops, mfs, 0);
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 MALLOC(mfsp, struct mfsnode *, sizeof *mfsp, M_MFSNODE,
333 minnum = (int)curproc->p_pid;
335 dev = make_dev(&mfs_ops, minnum, UID_ROOT, GID_WHEEL, 0600,
337 /* It is not clear that these will get initialized otherwise */
338 dev->si_bsize_phys = DEV_BSIZE;
339 dev->si_iosize_max = DFLTPHYS;
341 mfsp->mfs_baseoff = args.base;
342 mfsp->mfs_size = args.size;
344 mfsp->mfs_td = curthread;
345 mfsp->mfs_active = 1;
346 bioq_init(&mfsp->bio_queue);
348 devfs_config(); /* sync devfs work */
349 ksnprintf(devname, sizeof(devname), "/dev/mfs%d", minnum);
350 nlookup_init(&nd, devname, UIO_SYSSPACE, 0);
352 error = nlookup(&nd);
354 devvp = nd.nl_nch.ncp->nc_vp;
357 error = vget(devvp, LK_SHARED);
366 * Our 'block' device must be backed by a VM object. Theoretically
367 * we could use the anonymous memory VM object supplied by userland,
368 * but it would be somewhat of a complex task to deal with it
369 * that way since it would result in I/O requests which supply
370 * the VM pages from our own object.
372 * vnode_pager_alloc() is typically called when a VM object is
373 * being referenced externally. We have to undo the refs for
374 * the self reference between vnode and object.
376 vnode_pager_setsize(devvp, args.size);
378 /* Save "mounted from" info for mount point (NULL pad)*/
379 copyinstr(args.fspec, /* device name*/
380 mp->mnt_stat.f_mntfromname, /* save area*/
381 MNAMELEN - 1, /* max size*/
382 &size); /* real size*/
383 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
384 /* vref is eaten by mount? */
386 error = ffs_mountfs(devvp, mp, M_MFSNODE);
388 mfsp->mfs_active = 0;
393 * Initialize FS stat information in mount struct; uses
394 * mp->mnt_stat.f_mntfromname.
396 * This code is common to root and non-root mounts
398 VFS_STATFS(mp, &mp->mnt_stat, cred);
402 error_2: /* error with devvp held*/
405 error_1: /* no state to back out*/
408 destroy_dev(mfsp->mfs_dev);
409 mfsp->mfs_dev = NULL;
411 FREE(mfsp, M_MFSNODE);
419 * Used to grab the process and keep it in the kernel to service
420 * memory filesystem I/O requests.
422 * Loop servicing I/O requests.
423 * Copy the requested data into or out of the memory filesystem
428 mfs_start(struct mount *mp, int flags)
430 struct vnode *vp = VFSTOUFS(mp)->um_devvp;
431 struct mfsnode *mfsp = vp->v_rdev->si_drv1;
435 thread_t td = curthread;
438 * We must prevent the system from trying to swap
439 * out or kill ( when swap space is low, see vm/pageout.c ) the
440 * process. A deadlock can occur if the process is swapped out,
441 * and the system can loop trying to kill the unkillable ( while
442 * references exist ) MFS process when swap space is low.
449 while (mfsp->mfs_active) {
452 while ((bio = bioq_first(&mfsp->bio_queue)) != NULL) {
453 bioq_remove(&mfsp->bio_queue, bio);
464 * If a non-ignored signal is received, try to unmount.
465 * If that fails, clear the signal (it has been "processed"),
466 * otherwise we will loop here, as tsleep will always return
470 * Note that dounmount() may fail if work was queued after
471 * we slept. We have to jump hoops here to make sure that we
472 * process any buffers after the sleep, before we dounmount()
476 if (dounmount(mp, 0) != 0) {
477 KKASSERT(td->td_proc);
478 sig = CURSIG(td->td_lwp);
480 lwp_delsig(td->td_lwp, sig);
483 else if (tsleep((caddr_t)mfsp, PCATCH, "mfsidl", 0))
484 gotsig++; /* try to unmount in next pass */
488 destroy_dev(mfsp->mfs_dev);
489 mfsp->mfs_dev = NULL;
491 FREE(mfsp, M_MFSNODE);
496 * Get file system statistics.
499 mfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
503 error = ffs_statfs(mp, sbp, cred);
504 sbp->f_type = mp->mnt_vfc->vfc_typenum;
509 * Memory based filesystem initialization.
512 mfs_init(struct vfsconf *vfsp)
518 * Memory file system I/O.
520 * Trivial on the HP since buffer has already been mapping into KVA space.
522 * Read and Write are handled with a simple copyin and copyout.
524 * We also partially support VOP_FREEBLKS(). We can't implement
525 * completely -- for example, on fragments or inode metadata, but we can
526 * implement it for page-aligned requests.
529 mfs_doio(struct bio *bio, struct mfsnode *mfsp)
531 struct buf *bp = bio->bio_buf;
532 caddr_t base = mfsp->mfs_baseoff + bio->bio_offset;
536 case BUF_CMD_FREEBLKS:
538 * Implement FREEBLKS, which allows the filesystem to tell
539 * a block device when blocks are no longer needed (like when
540 * a file is deleted). We use the hook to MADV_FREE the VM.
541 * This makes an MFS filesystem work as well or better then
542 * a sun-style swap-mounted filesystem.
544 bytes = bp->b_bcount;
546 if ((vm_offset_t)base & PAGE_MASK) {
547 int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK);
552 struct madvise_args uap;
556 bzero(&uap, sizeof(uap));
559 uap.behav = MADV_FREE;
567 * Read data from our 'memory' disk
569 bp->b_error = copyin(base, bp->b_data, bp->b_bcount);
573 * Write data to our 'memory' disk
575 bp->b_error = copyout(bp->b_data, base, bp->b_bcount);
578 panic("mfs: bad b_cmd %d\n", bp->b_cmd);
581 bp->b_flags |= B_ERROR;