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34 * @(#)fdesc_vfsops.c 8.4 (Berkeley) 1/21/94
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/filedesc.h>
46 #include <sys/kernel.h>
49 #include <sys/mutex.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
53 #include <sys/racct.h>
54 #include <sys/resourcevar.h>
55 #include <sys/vnode.h>
57 #include <fs/fdescfs/fdesc.h>
59 static MALLOC_DEFINE(M_FDESCMNT, "fdesc_mount", "FDESC mount structure");
61 static vfs_cmount_t fdesc_cmount;
62 static vfs_mount_t fdesc_mount;
63 static vfs_unmount_t fdesc_unmount;
64 static vfs_statfs_t fdesc_statfs;
65 static vfs_root_t fdesc_root;
68 * Compatibility shim for old mount(2) system call.
71 fdesc_cmount(struct mntarg *ma, void *data, uint64_t flags)
74 return kernel_mount(ma, flags);
78 * Mount the per-process file descriptors (/dev/fd)
81 fdesc_mount(struct mount *mp)
83 struct fdescmount *fmp;
84 struct thread *td = curthread;
88 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_FDESCFS))
94 if (mp->mnt_flag & (MNT_UPDATE | MNT_ROOTFS))
97 fmp = malloc(sizeof(struct fdescmount),
98 M_FDESCMNT, M_WAITOK); /* XXX */
101 * We need to initialize a few bits of our local mount point struct to
102 * avoid confusion in allocvp.
106 if (vfs_getopt(mp->mnt_optnew, "linrdlnk", NULL, NULL) == 0)
107 fmp->flags |= FMNT_LINRDLNKF;
108 error = fdesc_allocvp(Froot, -1, FD_ROOT, mp, &rvp);
110 free(fmp, M_FDESCMNT);
115 rvp->v_vflag |= VV_ROOT;
118 /* XXX -- don't mark as local to work around fts() problems */
119 /*mp->mnt_flag |= MNT_LOCAL;*/
122 vfs_mountedfrom(mp, "fdescfs");
127 fdesc_unmount(struct mount *mp, int mntflags)
129 struct fdescmount *fmp;
134 if (mntflags & MNT_FORCE) {
135 /* The hash mutex protects the private mount flags. */
136 mtx_lock(&fdesc_hashmtx);
137 fmp->flags |= FMNT_UNMOUNTF;
138 mtx_unlock(&fdesc_hashmtx);
143 * Clear out buffer cache. I don't think we
144 * ever get anything cached at this level at the
145 * moment, but who knows...
147 * There is 1 extra root vnode reference corresponding
150 if ((error = vflush(mp, 1, flags, curthread)) != 0)
154 * Finally, throw away the fdescmount structure.
157 free(fmp, M_FDESCMNT);
162 fdesc_root(struct mount *mp, int flags, struct vnode **vpp)
167 * Return locked reference to root.
169 vp = VFSTOFDESC(mp)->f_root;
170 vget(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
176 fdesc_statfs(struct mount *mp, struct statfs *sbp)
179 struct filedesc *fdp;
189 * Compute number of free file descriptors.
190 * [ Strange results will ensue if the open file
191 * limit is ever reduced below the current number
194 lim = lim_cur(td, RLIMIT_NOFILE);
195 fdp = td->td_proc->p_fd;
197 limit = racct_get_limit(td->td_proc, RACCT_NOFILE);
200 last = min(fdp->fd_nfiles, lim);
202 for (i = fdp->fd_freefile; i < last; i++)
203 if (fdp->fd_ofiles[i].fde_file == NULL)
207 * Adjust for the fact that the fdesc array may not
208 * have been fully allocated yet.
210 if (fdp->fd_nfiles < lim)
211 freefd += (lim - fdp->fd_nfiles);
212 FILEDESC_SUNLOCK(fdp);
215 sbp->f_bsize = DEV_BSIZE;
216 sbp->f_iosize = DEV_BSIZE;
217 sbp->f_blocks = 2; /* 1K to keep df happy */
220 sbp->f_files = lim + 1; /* Allow for "." */
221 sbp->f_ffree = freefd; /* See comments above */
225 static struct vfsops fdesc_vfsops = {
226 .vfs_cmount = fdesc_cmount,
227 .vfs_init = fdesc_init,
228 .vfs_mount = fdesc_mount,
229 .vfs_root = fdesc_root,
230 .vfs_statfs = fdesc_statfs,
231 .vfs_uninit = fdesc_uninit,
232 .vfs_unmount = fdesc_unmount,
235 VFS_SET(fdesc_vfsops, fdescfs, VFCF_SYNTHETIC | VFCF_JAIL);