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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/sysmsg.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
= {
102 .vfs_mount
= mfs_mount
,
103 .vfs_start
= mfs_start
,
104 .vfs_unmount
= ffs_unmount
,
105 .vfs_root
= ufs_root
,
106 .vfs_quotactl
= ufs_quotactl
,
107 .vfs_statfs
= mfs_statfs
,
108 .vfs_sync
= ffs_sync
,
109 .vfs_vget
= ffs_vget
,
110 .vfs_fhtovp
= ffs_fhtovp
,
111 .vfs_checkexp
= ufs_check_export
,
112 .vfs_vptofh
= ffs_vptofh
,
116 VFS_SET(mfs_vfsops
, mfs
, 0);
117 MODULE_VERSION(mfs
, 1);
120 * We allow the underlying MFS block device to be opened and read.
123 mfsopen(struct dev_open_args
*ap
)
125 cdev_t dev
= ap
->a_head
.a_dev
;
128 if (ap
->a_oflags
& FWRITE
)
137 mfsclose(struct dev_close_args
*ap
)
139 cdev_t dev
= ap
->a_head
.a_dev
;
140 struct mfsnode
*mfsp
;
142 if ((mfsp
= dev
->si_drv1
) == NULL
)
144 mfsp
->mfs_active
= 0;
145 wakeup((caddr_t
)mfsp
);
150 mfsstrategy(struct dev_strategy_args
*ap
)
152 cdev_t dev
= ap
->a_head
.a_dev
;
153 struct bio
*bio
= ap
->a_bio
;
154 struct buf
*bp
= bio
->bio_buf
;
155 off_t boff
= bio
->bio_offset
;
156 off_t eoff
= boff
+ bp
->b_bcount
;
157 struct mfsnode
*mfsp
;
159 if ((mfsp
= dev
->si_drv1
) == NULL
) {
165 if (eoff
> mfsp
->mfs_size
) {
166 if (boff
> mfsp
->mfs_size
|| (bp
->b_flags
& B_BNOCLIP
))
169 * Return EOF by completing the I/O with 0 bytes transfered.
170 * Set B_INVAL to indicate that any data in the buffer is not
173 if (boff
== mfsp
->mfs_size
) {
174 bp
->b_resid
= bp
->b_bcount
;
175 bp
->b_flags
|= B_INVAL
;
178 bp
->b_bcount
= mfsp
->mfs_size
- boff
;
184 if (mfsp
->mfs_td
== curthread
) {
187 bioq_insert_tail(&mfsp
->bio_queue
, bio
);
188 wakeup((caddr_t
)mfsp
);
193 * Failure conditions on bio
196 bp
->b_error
= EINVAL
;
198 bp
->b_flags
|= B_ERROR
| B_INVAL
;
207 * Called when mounting local physical media
211 * mp mount point structure
212 * path NULL (flag for root mount!!!)
215 * p process (user credentials check [statfs])
218 * mp mount point structure
219 * path path to mount point
220 * data pointer to argument struct in user space
221 * ndp mount point namei() return (used for
222 * credentials on reload), reused to look
224 * p process (user credentials check)
227 * !0 error number (errno.h)
232 * mount point is locked
234 * mount point is locked
237 * A NULL path can be used for a flag since the mount
238 * system call will fail with EFAULT in copyinstr in
239 * namei() if it is a genuine NULL from the user.
243 mfs_mount(struct mount
*mp
, char *path
, caddr_t data
, struct ucred
*cred
)
246 struct mfs_args args
;
247 struct ufsmount
*ump
;
249 struct mfsnode
*mfsp
;
250 struct nlookupdata nd
;
259 * Use NULL path to flag a root mount
264 * Mounting root file system
269 panic("mfs_mount: mount MFS as root: not configured!");
276 * Mounting non-root file system or updating a file system
280 /* copy in user arguments*/
281 error
= copyin(data
, (caddr_t
)&args
, sizeof (struct mfs_args
));
286 * If updating, check whether changing from read-only to
287 * read/write; if there is no device name, that's all we do.
289 if (mp
->mnt_flag
& MNT_UPDATE
) {
297 if (fs
->fs_ronly
== 0 && (mp
->mnt_flag
& MNT_RDONLY
)) {
299 if (mp
->mnt_flag
& MNT_FORCE
)
301 error
= ffs_flushfiles(mp
, flags
);
305 if (fs
->fs_ronly
&& (mp
->mnt_kern_flag
& MNTK_WANTRDWR
)) {
306 /* XXX reopen the device vnode read-write */
309 /* if not updating name...*/
310 if (args
.fspec
== 0) {
312 * Process export requests. Jumping to "success"
313 * will return the vfs_export() error code.
315 error
= vfs_export(mp
, &ump
->um_export
, &args
.export
);
319 /* XXX MFS does not support name updating*/
324 * Do the MALLOC before the make_dev since doing so afterward
325 * might cause a bogus v_data pointer to get dereferenced
326 * elsewhere if MALLOC should block.
328 mfsp
= kmalloc(sizeof *mfsp
, M_MFSNODE
, M_WAITOK
| M_ZERO
);
330 minnum
= (int)curproc
->p_pid
;
332 dev
= make_dev(&mfs_ops
, minnum
, UID_ROOT
, GID_WHEEL
, 0600,
334 /* It is not clear that these will get initialized otherwise */
335 dev
->si_bsize_phys
= DEV_BSIZE
;
336 dev
->si_iosize_max
= MAXPHYS
;
338 mfsp
->mfs_baseoff
= args
.base
;
339 mfsp
->mfs_size
= args
.size
;
341 mfsp
->mfs_td
= curthread
;
342 mfsp
->mfs_active
= 1;
343 bioq_init(&mfsp
->bio_queue
);
345 devfs_config(); /* sync devfs work */
346 ksnprintf(devname
, sizeof(devname
), "/dev/mfs%d", minnum
);
347 nlookup_init(&nd
, devname
, UIO_SYSSPACE
, 0);
349 error
= nlookup(&nd
);
351 devvp
= nd
.nl_nch
.ncp
->nc_vp
;
354 error
= vget(devvp
, LK_SHARED
);
363 * Our 'block' device must be backed by a VM object. Theoretically
364 * we could use the anonymous memory VM object supplied by userland,
365 * but it would be somewhat of a complex task to deal with it
366 * that way since it would result in I/O requests which supply
367 * the VM pages from our own object.
369 * vnode_pager_alloc() is typically called when a VM object is
370 * being referenced externally. We have to undo the refs for
371 * the self reference between vnode and object.
373 vnode_pager_setsize(devvp
, args
.size
);
375 /* Save "mounted from" info for mount point (NULL pad)*/
376 copyinstr(args
.fspec
, /* device name*/
377 mp
->mnt_stat
.f_mntfromname
, /* save area*/
378 MNAMELEN
- 1, /* max size*/
379 &size
); /* real size*/
380 bzero(mp
->mnt_stat
.f_mntfromname
+ size
, MNAMELEN
- size
);
381 /* vref is eaten by mount? */
383 error
= ffs_mountfs(devvp
, mp
, M_MFSNODE
);
385 mfsp
->mfs_active
= 0;
390 * Initialize FS stat information in mount struct; uses
391 * mp->mnt_stat.f_mntfromname.
393 * This code is common to root and non-root mounts
395 VFS_STATFS(mp
, &mp
->mnt_stat
, cred
);
398 * Mark VFS_START MPSAFE; this is to avoid accessing
399 * per-mount token after VFS_START exits
401 mp
->mnt_kern_flag
|= MNTK_ST_MPSAFE
;
405 error_2
: /* error with devvp held*/
408 error_1
: /* no state to back out*/
411 destroy_dev(mfsp
->mfs_dev
);
412 mfsp
->mfs_dev
= NULL
;
414 kfree(mfsp
, M_MFSNODE
);
422 * Used to grab the process and keep it in the kernel to service
423 * memory filesystem I/O requests.
425 * Loop servicing I/O requests.
426 * Copy the requested data into or out of the memory filesystem
431 mfs_start(struct mount
*mp
, int flags
)
433 struct vnode
*vp
= VFSTOUFS(mp
)->um_devvp
;
434 struct mfsnode
*mfsp
= vp
->v_rdev
->si_drv1
;
438 thread_t td
= curthread
;
441 * We must prevent the system from trying to swap
442 * out or kill ( when swap space is low, see vm/pageout.c ) the
443 * process. A deadlock can occur if the process is swapped out,
444 * and the system can loop trying to kill the unkillable ( while
445 * references exist ) MFS process when swap space is low.
452 while (mfsp
->mfs_active
) {
455 while ((bio
= bioq_takefirst(&mfsp
->bio_queue
)) != NULL
) {
466 * If a non-ignored signal is received, try to unmount.
467 * If that fails, clear the signal (it has been "processed"),
468 * otherwise we will loop here, as tsleep will always return
472 * Note that dounmount() may fail if work was queued after
473 * we slept. We have to jump hoops here to make sure that we
474 * process any buffers after the sleep, before we dounmount()
478 if (dounmount(mp
, 0, 0) != 0) {
479 KKASSERT(td
->td_proc
);
480 lwkt_gettoken(&td
->td_proc
->p_token
);
481 sig
= CURSIG(td
->td_lwp
);
483 spin_lock(&td
->td_lwp
->lwp_spin
);
484 lwp_delsig(td
->td_lwp
, sig
, 1);
485 spin_unlock(&td
->td_lwp
->lwp_spin
);
487 lwkt_reltoken(&td
->td_proc
->p_token
);
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 struct sysmsg sysmsg
;
565 bzero(&sysmsg
, sizeof(sysmsg
));
566 bzero(&uap
, sizeof(uap
));
569 uap
.behav
= MADV_FREE
;
570 sys_madvise(&sysmsg
, &uap
);
577 * Read data from our 'memory' disk
579 bp
->b_error
= copyin(base
, bp
->b_data
, bp
->b_bcount
);
583 * Write data to our 'memory' disk
585 bp
->b_error
= copyout(bp
->b_data
, base
, bp
->b_bcount
);
588 panic("mfs: bad b_cmd %d", bp
->b_cmd
);
591 bp
->b_flags
|= B_ERROR
;