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