diff options
Diffstat (limited to 'fs/afs/mntpt.c')
| -rw-r--r-- | fs/afs/mntpt.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c new file mode 100644 index 0000000000..97f50e9fd9 --- /dev/null +++ b/fs/afs/mntpt.c @@ -0,0 +1,219 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* mountpoint management + * + * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/gfp.h> +#include <linux/fs_context.h> +#include "internal.h" + + +static struct dentry *afs_mntpt_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags); +static int afs_mntpt_open(struct inode *inode, struct file *file); +static void afs_mntpt_expiry_timed_out(struct work_struct *work); + +const struct file_operations afs_mntpt_file_operations = { + .open = afs_mntpt_open, + .llseek = noop_llseek, +}; + +const struct inode_operations afs_mntpt_inode_operations = { + .lookup = afs_mntpt_lookup, + .readlink = page_readlink, + .getattr = afs_getattr, +}; + +const struct inode_operations afs_autocell_inode_operations = { + .getattr = afs_getattr, +}; + +static LIST_HEAD(afs_vfsmounts); +static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out); + +static unsigned long afs_mntpt_expiry_timeout = 10 * 60; + +static const char afs_root_volume[] = "root.cell"; + +/* + * no valid lookup procedure on this sort of dir + */ +static struct dentry *afs_mntpt_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + _enter("%p,%p{%pd2}", dir, dentry, dentry); + return ERR_PTR(-EREMOTE); +} + +/* + * no valid open procedure on this sort of dir + */ +static int afs_mntpt_open(struct inode *inode, struct file *file) +{ + _enter("%p,%p{%pD2}", inode, file, file); + return -EREMOTE; +} + +/* + * Set the parameters for the proposed superblock. + */ +static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) +{ + struct afs_fs_context *ctx = fc->fs_private; + struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb); + struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt)); + struct afs_cell *cell; + const char *p; + int ret; + + if (fc->net_ns != src_as->net_ns) { + put_net(fc->net_ns); + fc->net_ns = get_net(src_as->net_ns); + } + + if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) { + ctx->type = AFSVL_RWVOL; + ctx->force = true; + } + if (ctx->cell) { + afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_mntpt); + ctx->cell = NULL; + } + if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) { + /* if the directory is a pseudo directory, use the d_name */ + unsigned size = mntpt->d_name.len; + + if (size < 2) + return -ENOENT; + + p = mntpt->d_name.name; + if (mntpt->d_name.name[0] == '.') { + size--; + p++; + ctx->type = AFSVL_RWVOL; + ctx->force = true; + } + if (size > AFS_MAXCELLNAME) + return -ENAMETOOLONG; + + cell = afs_lookup_cell(ctx->net, p, size, NULL, false); + if (IS_ERR(cell)) { + pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt); + return PTR_ERR(cell); + } + ctx->cell = cell; + + ctx->volname = afs_root_volume; + ctx->volnamesz = sizeof(afs_root_volume) - 1; + } else { + /* read the contents of the AFS special symlink */ + struct page *page; + loff_t size = i_size_read(d_inode(mntpt)); + char *buf; + + if (src_as->cell) + ctx->cell = afs_use_cell(src_as->cell, afs_cell_trace_use_mntpt); + + if (size < 2 || size > PAGE_SIZE - 1) + return -EINVAL; + + page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL); + if (IS_ERR(page)) + return PTR_ERR(page); + + buf = kmap(page); + ret = -EINVAL; + if (buf[size - 1] == '.') + ret = vfs_parse_fs_string(fc, "source", buf, size - 1); + kunmap(page); + put_page(page); + if (ret < 0) + return ret; + } + + return 0; +} + +/* + * create a vfsmount to be automounted + */ +static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) +{ + struct fs_context *fc; + struct vfsmount *mnt; + int ret; + + BUG_ON(!d_inode(mntpt)); + + fc = fs_context_for_submount(&afs_fs_type, mntpt); + if (IS_ERR(fc)) + return ERR_CAST(fc); + + ret = afs_mntpt_set_params(fc, mntpt); + if (!ret) + mnt = fc_mount(fc); + else + mnt = ERR_PTR(ret); + + put_fs_context(fc); + return mnt; +} + +/* + * handle an automount point + */ +struct vfsmount *afs_d_automount(struct path *path) +{ + struct vfsmount *newmnt; + + _enter("{%pd}", path->dentry); + + newmnt = afs_mntpt_do_automount(path->dentry); + if (IS_ERR(newmnt)) + return newmnt; + + mntget(newmnt); /* prevent immediate expiration */ + mnt_set_expiry(newmnt, &afs_vfsmounts); + queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, + afs_mntpt_expiry_timeout * HZ); + _leave(" = %p", newmnt); + return newmnt; +} + +/* + * handle mountpoint expiry timer going off + */ +static void afs_mntpt_expiry_timed_out(struct work_struct *work) +{ + _enter(""); + + if (!list_empty(&afs_vfsmounts)) { + mark_mounts_for_expiry(&afs_vfsmounts); + queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, + afs_mntpt_expiry_timeout * HZ); + } + + _leave(""); +} + +/* + * kill the AFS mountpoint timer if it's still running + */ +void afs_mntpt_kill_timer(void) +{ + _enter(""); + + ASSERT(list_empty(&afs_vfsmounts)); + cancel_delayed_work_sync(&afs_mntpt_expiry_timer); +} |