From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/afs/dynroot.c | 397 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 397 insertions(+) create mode 100644 fs/afs/dynroot.c (limited to 'fs/afs/dynroot.c') diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c new file mode 100644 index 000000000..9937993cf --- /dev/null +++ b/fs/afs/dynroot.c @@ -0,0 +1,397 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS dynamic root handling + * + * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include "internal.h" + +static atomic_t afs_autocell_ino; + +/* + * iget5() comparator for inode created by autocell operations + * + * These pseudo inodes don't match anything. + */ +static int afs_iget5_pseudo_test(struct inode *inode, void *opaque) +{ + return 0; +} + +/* + * iget5() inode initialiser + */ +static int afs_iget5_pseudo_set(struct inode *inode, void *opaque) +{ + struct afs_super_info *as = AFS_FS_S(inode->i_sb); + struct afs_vnode *vnode = AFS_FS_I(inode); + struct afs_fid *fid = opaque; + + vnode->volume = as->volume; + vnode->fid = *fid; + inode->i_ino = fid->vnode; + inode->i_generation = fid->unique; + return 0; +} + +/* + * Create an inode for a dynamic root directory or an autocell dynamic + * automount dir. + */ +struct inode *afs_iget_pseudo_dir(struct super_block *sb, bool root) +{ + struct afs_super_info *as = AFS_FS_S(sb); + struct afs_vnode *vnode; + struct inode *inode; + struct afs_fid fid = {}; + + _enter(""); + + if (as->volume) + fid.vid = as->volume->vid; + if (root) { + fid.vnode = 1; + fid.unique = 1; + } else { + fid.vnode = atomic_inc_return(&afs_autocell_ino); + fid.unique = 0; + } + + inode = iget5_locked(sb, fid.vnode, + afs_iget5_pseudo_test, afs_iget5_pseudo_set, &fid); + if (!inode) { + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); + } + + _debug("GOT INODE %p { ino=%lu, vl=%llx, vn=%llx, u=%x }", + inode, inode->i_ino, fid.vid, fid.vnode, fid.unique); + + vnode = AFS_FS_I(inode); + + /* there shouldn't be an existing inode */ + BUG_ON(!(inode->i_state & I_NEW)); + + netfs_inode_init(&vnode->netfs, NULL); + inode->i_size = 0; + inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; + if (root) { + inode->i_op = &afs_dynroot_inode_operations; + inode->i_fop = &simple_dir_operations; + } else { + inode->i_op = &afs_autocell_inode_operations; + } + set_nlink(inode, 2); + inode->i_uid = GLOBAL_ROOT_UID; + inode->i_gid = GLOBAL_ROOT_GID; + inode->i_ctime = inode->i_atime = inode->i_mtime = current_time(inode); + inode->i_blocks = 0; + inode->i_generation = 0; + + set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags); + if (!root) { + set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags); + inode->i_flags |= S_AUTOMOUNT; + } + + inode->i_flags |= S_NOATIME; + unlock_new_inode(inode); + _leave(" = %p", inode); + return inode; +} + +/* + * Probe to see if a cell may exist. This prevents positive dentries from + * being created unnecessarily. + */ +static int afs_probe_cell_name(struct dentry *dentry) +{ + struct afs_cell *cell; + struct afs_net *net = afs_d2net(dentry); + const char *name = dentry->d_name.name; + size_t len = dentry->d_name.len; + char *result = NULL; + int ret; + + /* Names prefixed with a dot are R/W mounts. */ + if (name[0] == '.') { + if (len == 1) + return -EINVAL; + name++; + len--; + } + + cell = afs_find_cell(net, name, len, afs_cell_trace_use_probe); + if (!IS_ERR(cell)) { + afs_unuse_cell(net, cell, afs_cell_trace_unuse_probe); + return 0; + } + + ret = dns_query(net->net, "afsdb", name, len, "srv=1", + &result, NULL, false); + if (ret == -ENODATA || ret == -ENOKEY || ret == 0) + ret = -ENOENT; + if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) { + struct dns_server_list_v1_header *v1 = (void *)result; + + if (v1->hdr.zero == 0 && + v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST && + v1->hdr.version == 1 && + (v1->status != DNS_LOOKUP_GOOD && + v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) + return -ENOENT; + + } + + kfree(result); + return ret; +} + +/* + * Try to auto mount the mountpoint with pseudo directory, if the autocell + * operation is setted. + */ +struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir) +{ + struct afs_vnode *vnode = AFS_FS_I(dir); + struct inode *inode; + int ret = -ENOENT; + + _enter("%p{%pd}, {%llx:%llu}", + dentry, dentry, vnode->fid.vid, vnode->fid.vnode); + + if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags)) + goto out; + + ret = afs_probe_cell_name(dentry); + if (ret < 0) + goto out; + + inode = afs_iget_pseudo_dir(dir->i_sb, false); + if (IS_ERR(inode)) { + ret = PTR_ERR(inode); + goto out; + } + + _leave("= %p", inode); + return inode; + +out: + _leave("= %d", ret); + return ret == -ENOENT ? NULL : ERR_PTR(ret); +} + +/* + * Look up @cell in a dynroot directory. This is a substitution for the + * local cell name for the net namespace. + */ +static struct dentry *afs_lookup_atcell(struct dentry *dentry) +{ + struct afs_cell *cell; + struct afs_net *net = afs_d2net(dentry); + struct dentry *ret; + char *name; + int len; + + if (!net->ws_cell) + return ERR_PTR(-ENOENT); + + ret = ERR_PTR(-ENOMEM); + name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL); + if (!name) + goto out_p; + + down_read(&net->cells_lock); + cell = net->ws_cell; + if (cell) { + len = cell->name_len; + memcpy(name, cell->name, len + 1); + } + up_read(&net->cells_lock); + + ret = ERR_PTR(-ENOENT); + if (!cell) + goto out_n; + + ret = lookup_one_len(name, dentry->d_parent, len); + + /* We don't want to d_add() the @cell dentry here as we don't want to + * the cached dentry to hide changes to the local cell name. + */ + +out_n: + kfree(name); +out_p: + return ret; +} + +/* + * Look up an entry in a dynroot directory. + */ +static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + _enter("%pd", dentry); + + ASSERTCMP(d_inode(dentry), ==, NULL); + + if (flags & LOOKUP_CREATE) + return ERR_PTR(-EOPNOTSUPP); + + if (dentry->d_name.len >= AFSNAMEMAX) { + _leave(" = -ENAMETOOLONG"); + return ERR_PTR(-ENAMETOOLONG); + } + + if (dentry->d_name.len == 5 && + memcmp(dentry->d_name.name, "@cell", 5) == 0) + return afs_lookup_atcell(dentry); + + return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry); +} + +const struct inode_operations afs_dynroot_inode_operations = { + .lookup = afs_dynroot_lookup, +}; + +/* + * Dirs in the dynamic root don't need revalidation. + */ +static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags) +{ + return 1; +} + +const struct dentry_operations afs_dynroot_dentry_operations = { + .d_revalidate = afs_dynroot_d_revalidate, + .d_delete = always_delete_dentry, + .d_release = afs_d_release, + .d_automount = afs_d_automount, +}; + +/* + * Create a manually added cell mount directory. + * - The caller must hold net->proc_cells_lock + */ +int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell) +{ + struct super_block *sb = net->dynroot_sb; + struct dentry *root, *subdir; + int ret; + + if (!sb || atomic_read(&sb->s_active) == 0) + return 0; + + /* Let the ->lookup op do the creation */ + root = sb->s_root; + inode_lock(root->d_inode); + subdir = lookup_one_len(cell->name, root, cell->name_len); + if (IS_ERR(subdir)) { + ret = PTR_ERR(subdir); + goto unlock; + } + + /* Note that we're retaining an extra ref on the dentry */ + subdir->d_fsdata = (void *)1UL; + ret = 0; +unlock: + inode_unlock(root->d_inode); + return ret; +} + +/* + * Remove a manually added cell mount directory. + * - The caller must hold net->proc_cells_lock + */ +void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell) +{ + struct super_block *sb = net->dynroot_sb; + struct dentry *root, *subdir; + + if (!sb || atomic_read(&sb->s_active) == 0) + return; + + root = sb->s_root; + inode_lock(root->d_inode); + + /* Don't want to trigger a lookup call, which will re-add the cell */ + subdir = try_lookup_one_len(cell->name, root, cell->name_len); + if (IS_ERR_OR_NULL(subdir)) { + _debug("lookup %ld", PTR_ERR(subdir)); + goto no_dentry; + } + + _debug("rmdir %pd %u", subdir, d_count(subdir)); + + if (subdir->d_fsdata) { + _debug("unpin %u", d_count(subdir)); + subdir->d_fsdata = NULL; + dput(subdir); + } + dput(subdir); +no_dentry: + inode_unlock(root->d_inode); + _leave(""); +} + +/* + * Populate a newly created dynamic root with cell names. + */ +int afs_dynroot_populate(struct super_block *sb) +{ + struct afs_cell *cell; + struct afs_net *net = afs_sb2net(sb); + int ret; + + mutex_lock(&net->proc_cells_lock); + + net->dynroot_sb = sb; + hlist_for_each_entry(cell, &net->proc_cells, proc_link) { + ret = afs_dynroot_mkdir(net, cell); + if (ret < 0) + goto error; + } + + ret = 0; +out: + mutex_unlock(&net->proc_cells_lock); + return ret; + +error: + net->dynroot_sb = NULL; + goto out; +} + +/* + * When a dynamic root that's in the process of being destroyed, depopulate it + * of pinned directories. + */ +void afs_dynroot_depopulate(struct super_block *sb) +{ + struct afs_net *net = afs_sb2net(sb); + struct dentry *root = sb->s_root, *subdir, *tmp; + + /* Prevent more subdirs from being created */ + mutex_lock(&net->proc_cells_lock); + if (net->dynroot_sb == sb) + net->dynroot_sb = NULL; + mutex_unlock(&net->proc_cells_lock); + + if (root) { + inode_lock(root->d_inode); + + /* Remove all the pins for dirs created for manually added cells */ + list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) { + if (subdir->d_fsdata) { + subdir->d_fsdata = NULL; + dput(subdir); + } + } + + inode_unlock(root->d_inode); + } +} -- cgit v1.2.3