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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /fs/nfs/namespace.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/nfs/namespace.c')
-rw-r--r-- | fs/nfs/namespace.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c new file mode 100644 index 000000000..1f03445b5 --- /dev/null +++ b/fs/nfs/namespace.c @@ -0,0 +1,367 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/fs/nfs/namespace.c + * + * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> + * - Modified by David Howells <dhowells@redhat.com> + * + * NFS namespace + */ + +#include <linux/module.h> +#include <linux/dcache.h> +#include <linux/gfp.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/nfs_fs.h> +#include <linux/string.h> +#include <linux/sunrpc/clnt.h> +#include <linux/vfs.h> +#include <linux/sunrpc/gss_api.h> +#include "internal.h" +#include "nfs.h" + +#define NFSDBG_FACILITY NFSDBG_VFS + +static void nfs_expire_automounts(struct work_struct *work); + +static LIST_HEAD(nfs_automount_list); +static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); +int nfs_mountpoint_expiry_timeout = 500 * HZ; + +/* + * nfs_path - reconstruct the path given an arbitrary dentry + * @base - used to return pointer to the end of devname part of path + * @dentry_in - pointer to dentry + * @buffer - result buffer + * @buflen_in - length of buffer + * @flags - options (see below) + * + * Helper function for constructing the server pathname + * by arbitrary hashed dentry. + * + * This is mainly for use in figuring out the path on the + * server side when automounting on top of an existing partition + * and in generating /proc/mounts and friends. + * + * Supported flags: + * NFS_PATH_CANONICAL: ensure there is exactly one slash after + * the original device (export) name + * (if unset, the original name is returned verbatim) + */ +char *nfs_path(char **p, struct dentry *dentry_in, char *buffer, + ssize_t buflen_in, unsigned flags) +{ + char *end; + int namelen; + unsigned seq; + const char *base; + struct dentry *dentry; + ssize_t buflen; + +rename_retry: + buflen = buflen_in; + dentry = dentry_in; + end = buffer+buflen; + *--end = '\0'; + buflen--; + + seq = read_seqbegin(&rename_lock); + rcu_read_lock(); + while (1) { + spin_lock(&dentry->d_lock); + if (IS_ROOT(dentry)) + break; + namelen = dentry->d_name.len; + buflen -= namelen + 1; + if (buflen < 0) + goto Elong_unlock; + end -= namelen; + memcpy(end, dentry->d_name.name, namelen); + *--end = '/'; + spin_unlock(&dentry->d_lock); + dentry = dentry->d_parent; + } + if (read_seqretry(&rename_lock, seq)) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto rename_retry; + } + if ((flags & NFS_PATH_CANONICAL) && *end != '/') { + if (--buflen < 0) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto Elong; + } + *--end = '/'; + } + *p = end; + base = dentry->d_fsdata; + if (!base) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + WARN_ON(1); + return end; + } + namelen = strlen(base); + if (*end == '/') { + /* Strip off excess slashes in base string */ + while (namelen > 0 && base[namelen - 1] == '/') + namelen--; + } + buflen -= namelen; + if (buflen < 0) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + goto Elong; + } + end -= namelen; + memcpy(end, base, namelen); + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + return end; +Elong_unlock: + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + if (read_seqretry(&rename_lock, seq)) + goto rename_retry; +Elong: + return ERR_PTR(-ENAMETOOLONG); +} +EXPORT_SYMBOL_GPL(nfs_path); + +/* + * nfs_d_automount - Handle crossing a mountpoint on the server + * @path - The mountpoint + * + * When we encounter a mountpoint on the server, we want to set up + * a mountpoint on the client too, to prevent inode numbers from + * colliding, and to allow "df" to work properly. + * On NFSv4, we also want to allow for the fact that different + * filesystems may be migrated to different servers in a failover + * situation, and that different filesystems may want to use + * different security flavours. + */ +struct vfsmount *nfs_d_automount(struct path *path) +{ + struct nfs_fs_context *ctx; + struct fs_context *fc; + struct vfsmount *mnt = ERR_PTR(-ENOMEM); + struct nfs_server *server = NFS_SB(path->dentry->d_sb); + struct nfs_client *client = server->nfs_client; + int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout); + int ret; + + if (IS_ROOT(path->dentry)) + return ERR_PTR(-ESTALE); + + /* Open a new filesystem context, transferring parameters from the + * parent superblock, including the network namespace. + */ + fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry); + if (IS_ERR(fc)) + return ERR_CAST(fc); + + ctx = nfs_fc2context(fc); + ctx->clone_data.dentry = path->dentry; + ctx->clone_data.sb = path->dentry->d_sb; + ctx->clone_data.fattr = nfs_alloc_fattr(); + if (!ctx->clone_data.fattr) + goto out_fc; + + if (fc->net_ns != client->cl_net) { + put_net(fc->net_ns); + fc->net_ns = get_net(client->cl_net); + } + + /* for submounts we want the same server; referrals will reassign */ + memcpy(&ctx->nfs_server.address, &client->cl_addr, client->cl_addrlen); + ctx->nfs_server.addrlen = client->cl_addrlen; + ctx->nfs_server.port = server->port; + + ctx->version = client->rpc_ops->version; + ctx->minorversion = client->cl_minorversion; + ctx->nfs_mod = client->cl_nfs_mod; + __module_get(ctx->nfs_mod->owner); + + ret = client->rpc_ops->submount(fc, server); + if (ret < 0) { + mnt = ERR_PTR(ret); + goto out_fc; + } + + up_write(&fc->root->d_sb->s_umount); + mnt = vfs_create_mount(fc); + if (IS_ERR(mnt)) + goto out_fc; + + mntget(mnt); /* prevent immediate expiration */ + if (timeout <= 0) + goto out_fc; + + mnt_set_expiry(mnt, &nfs_automount_list); + schedule_delayed_work(&nfs_automount_task, timeout); + +out_fc: + put_fs_context(fc); + return mnt; +} + +static int +nfs_namespace_getattr(const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int query_flags) +{ + if (NFS_FH(d_inode(path->dentry))->size != 0) + return nfs_getattr(path, stat, request_mask, query_flags); + generic_fillattr(d_inode(path->dentry), stat); + return 0; +} + +static int +nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr) +{ + if (NFS_FH(d_inode(dentry))->size != 0) + return nfs_setattr(dentry, attr); + return -EACCES; +} + +const struct inode_operations nfs_mountpoint_inode_operations = { + .getattr = nfs_getattr, + .setattr = nfs_setattr, +}; + +const struct inode_operations nfs_referral_inode_operations = { + .getattr = nfs_namespace_getattr, + .setattr = nfs_namespace_setattr, +}; + +static void nfs_expire_automounts(struct work_struct *work) +{ + struct list_head *list = &nfs_automount_list; + int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout); + + mark_mounts_for_expiry(list); + if (!list_empty(list) && timeout > 0) + schedule_delayed_work(&nfs_automount_task, timeout); +} + +void nfs_release_automount_timer(void) +{ + if (list_empty(&nfs_automount_list)) + cancel_delayed_work(&nfs_automount_task); +} + +/** + * nfs_do_submount - set up mountpoint when crossing a filesystem boundary + * @fc: pointer to struct nfs_fs_context + * + */ +int nfs_do_submount(struct fs_context *fc) +{ + struct nfs_fs_context *ctx = nfs_fc2context(fc); + struct dentry *dentry = ctx->clone_data.dentry; + struct nfs_server *server; + char *buffer, *p; + int ret; + + /* create a new volume representation */ + server = ctx->nfs_mod->rpc_ops->clone_server(NFS_SB(ctx->clone_data.sb), + ctx->mntfh, + ctx->clone_data.fattr, + ctx->selected_flavor); + + if (IS_ERR(server)) + return PTR_ERR(server); + + ctx->server = server; + + buffer = kmalloc(4096, GFP_USER); + if (!buffer) + return -ENOMEM; + + ctx->internal = true; + ctx->clone_data.inherited_bsize = ctx->clone_data.sb->s_blocksize_bits; + + p = nfs_devname(dentry, buffer, 4096); + if (IS_ERR(p)) { + nfs_errorf(fc, "NFS: Couldn't determine submount pathname"); + ret = PTR_ERR(p); + } else { + ret = vfs_parse_fs_string(fc, "source", p, buffer + 4096 - p); + if (!ret) + ret = vfs_get_tree(fc); + } + kfree(buffer); + return ret; +} +EXPORT_SYMBOL_GPL(nfs_do_submount); + +int nfs_submount(struct fs_context *fc, struct nfs_server *server) +{ + struct nfs_fs_context *ctx = nfs_fc2context(fc); + struct dentry *dentry = ctx->clone_data.dentry; + struct dentry *parent = dget_parent(dentry); + int err; + + /* Look it up again to get its attributes */ + err = server->nfs_client->rpc_ops->lookup(d_inode(parent), dentry, + ctx->mntfh, ctx->clone_data.fattr, + NULL); + dput(parent); + if (err != 0) + return err; + + ctx->selected_flavor = server->client->cl_auth->au_flavor; + return nfs_do_submount(fc); +} +EXPORT_SYMBOL_GPL(nfs_submount); + +static int param_set_nfs_timeout(const char *val, const struct kernel_param *kp) +{ + long num; + int ret; + + if (!val) + return -EINVAL; + ret = kstrtol(val, 0, &num); + if (ret) + return -EINVAL; + if (num > 0) { + if (num >= INT_MAX / HZ) + num = INT_MAX; + else + num *= HZ; + *((int *)kp->arg) = num; + if (!list_empty(&nfs_automount_list)) + mod_delayed_work(system_wq, &nfs_automount_task, num); + } else { + *((int *)kp->arg) = -1*HZ; + cancel_delayed_work(&nfs_automount_task); + } + return 0; +} + +static int param_get_nfs_timeout(char *buffer, const struct kernel_param *kp) +{ + long num = *((int *)kp->arg); + + if (num > 0) { + if (num >= INT_MAX - (HZ - 1)) + num = INT_MAX / HZ; + else + num = (num + (HZ - 1)) / HZ; + } else + num = -1; + return scnprintf(buffer, PAGE_SIZE, "%li\n", num); +} + +static const struct kernel_param_ops param_ops_nfs_timeout = { + .set = param_set_nfs_timeout, + .get = param_get_nfs_timeout, +}; +#define param_check_nfs_timeout(name, p) __param_check(name, p, int); + +module_param(nfs_mountpoint_expiry_timeout, nfs_timeout, 0644); +MODULE_PARM_DESC(nfs_mountpoint_expiry_timeout, + "Set the NFS automounted mountpoint timeout value (seconds)." + "Values <= 0 turn expiration off."); |