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![Christian Brauner](/assets/img/avatar_default.png)
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b
("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
350 lines
8.2 KiB
C
350 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/fs.h>
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#include <linux/gfp.h>
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#include <linux/nfs.h>
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#include <linux/nfs3.h>
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#include <linux/nfs_fs.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/nfsacl.h>
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#include "internal.h"
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#include "nfs3_fs.h"
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#define NFSDBG_FACILITY NFSDBG_PROC
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/*
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* nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for
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* caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl()
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* for explanations.
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*/
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static void nfs3_prepare_get_acl(struct posix_acl **p)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) {
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/* Not the first reader or sentinel already in place. */
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}
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}
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static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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/* Only cache the ACL if our sentinel is still in place. */
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posix_acl_dup(acl);
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if (cmpxchg(p, sentinel, acl) != sentinel)
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posix_acl_release(acl);
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}
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static void nfs3_abort_get_acl(struct posix_acl **p)
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{
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struct posix_acl *sentinel = uncached_acl_sentinel(current);
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/* Remove our sentinel upon failure. */
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cmpxchg(p, sentinel, ACL_NOT_CACHED);
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}
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struct posix_acl *nfs3_get_acl(struct inode *inode, int type, bool rcu)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct page *pages[NFSACL_MAXPAGES] = { };
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struct nfs3_getaclargs args = {
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.fh = NFS_FH(inode),
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/* The xdr layer may allocate pages here. */
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.pages = pages,
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};
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struct nfs3_getaclres res = {
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NULL,
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};
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struct rpc_message msg = {
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.rpc_argp = &args,
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.rpc_resp = &res,
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};
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int status, count;
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if (rcu)
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return ERR_PTR(-ECHILD);
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if (!nfs_server_capable(inode, NFS_CAP_ACLS))
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return ERR_PTR(-EOPNOTSUPP);
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status = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE);
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if (status < 0)
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return ERR_PTR(status);
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/*
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* Only get the access acl when explicitly requested: We don't
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* need it for access decisions, and only some applications use
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* it. Applications which request the access acl first are not
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* penalized from this optimization.
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*/
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if (type == ACL_TYPE_ACCESS)
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args.mask |= NFS_ACLCNT|NFS_ACL;
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if (S_ISDIR(inode->i_mode))
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args.mask |= NFS_DFACLCNT|NFS_DFACL;
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if (args.mask == 0)
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return NULL;
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dprintk("NFS call getacl\n");
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msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL];
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res.fattr = nfs_alloc_fattr();
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if (res.fattr == NULL)
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return ERR_PTR(-ENOMEM);
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if (args.mask & NFS_ACL)
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nfs3_prepare_get_acl(&inode->i_acl);
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if (args.mask & NFS_DFACL)
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nfs3_prepare_get_acl(&inode->i_default_acl);
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status = rpc_call_sync(server->client_acl, &msg, 0);
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dprintk("NFS reply getacl: %d\n", status);
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/* pages may have been allocated at the xdr layer. */
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for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
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__free_page(args.pages[count]);
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switch (status) {
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case 0:
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status = nfs_refresh_inode(inode, res.fattr);
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break;
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case -EPFNOSUPPORT:
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case -EPROTONOSUPPORT:
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dprintk("NFS_V3_ACL extension not supported; disabling\n");
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server->caps &= ~NFS_CAP_ACLS;
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fallthrough;
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case -ENOTSUPP:
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status = -EOPNOTSUPP;
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goto getout;
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default:
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goto getout;
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}
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if ((args.mask & res.mask) != args.mask) {
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status = -EIO;
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goto getout;
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}
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if (res.acl_access != NULL) {
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if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) ||
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res.acl_access->a_count == 0) {
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posix_acl_release(res.acl_access);
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res.acl_access = NULL;
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}
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}
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if (res.mask & NFS_ACL)
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nfs3_complete_get_acl(&inode->i_acl, res.acl_access);
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else
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forget_cached_acl(inode, ACL_TYPE_ACCESS);
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if (res.mask & NFS_DFACL)
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nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default);
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else
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forget_cached_acl(inode, ACL_TYPE_DEFAULT);
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nfs_free_fattr(res.fattr);
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if (type == ACL_TYPE_ACCESS) {
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posix_acl_release(res.acl_default);
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return res.acl_access;
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} else {
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posix_acl_release(res.acl_access);
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return res.acl_default;
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}
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getout:
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nfs3_abort_get_acl(&inode->i_acl);
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nfs3_abort_get_acl(&inode->i_default_acl);
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posix_acl_release(res.acl_access);
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posix_acl_release(res.acl_default);
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nfs_free_fattr(res.fattr);
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return ERR_PTR(status);
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}
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static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
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struct posix_acl *dfacl)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct nfs_fattr *fattr;
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struct page *pages[NFSACL_MAXPAGES];
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struct nfs3_setaclargs args = {
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.inode = inode,
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.mask = NFS_ACL,
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.acl_access = acl,
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.pages = pages,
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};
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struct rpc_message msg = {
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.rpc_argp = &args,
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.rpc_resp = &fattr,
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};
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int status = 0;
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if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL))
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goto out;
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status = -EOPNOTSUPP;
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if (!nfs_server_capable(inode, NFS_CAP_ACLS))
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goto out;
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/* We are doing this here because XDR marshalling does not
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* return any results, it BUGs. */
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status = -ENOSPC;
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if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
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goto out;
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if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
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goto out;
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if (S_ISDIR(inode->i_mode)) {
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args.mask |= NFS_DFACL;
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args.acl_default = dfacl;
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args.len = nfsacl_size(acl, dfacl);
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} else
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args.len = nfsacl_size(acl, NULL);
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if (args.len > NFS_ACL_INLINE_BUFSIZE) {
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unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT);
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status = -ENOMEM;
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do {
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args.pages[args.npages] = alloc_page(GFP_KERNEL);
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if (args.pages[args.npages] == NULL)
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goto out_freepages;
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args.npages++;
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} while (args.npages < npages);
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}
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dprintk("NFS call setacl\n");
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status = -ENOMEM;
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fattr = nfs_alloc_fattr();
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if (fattr == NULL)
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goto out_freepages;
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msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL];
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msg.rpc_resp = fattr;
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status = rpc_call_sync(server->client_acl, &msg, 0);
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nfs_access_zap_cache(inode);
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nfs_zap_acl_cache(inode);
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dprintk("NFS reply setacl: %d\n", status);
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switch (status) {
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case 0:
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status = nfs_refresh_inode(inode, fattr);
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break;
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case -EPFNOSUPPORT:
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case -EPROTONOSUPPORT:
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dprintk("NFS_V3_ACL SETACL RPC not supported"
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"(will not retry)\n");
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server->caps &= ~NFS_CAP_ACLS;
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fallthrough;
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case -ENOTSUPP:
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status = -EOPNOTSUPP;
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}
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nfs_free_fattr(fattr);
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out_freepages:
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while (args.npages != 0) {
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args.npages--;
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__free_page(args.pages[args.npages]);
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}
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out:
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return status;
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}
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int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
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struct posix_acl *dfacl)
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{
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int ret;
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ret = __nfs3_proc_setacls(inode, acl, dfacl);
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return (ret == -EOPNOTSUPP) ? 0 : ret;
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}
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int nfs3_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
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struct posix_acl *acl, int type)
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{
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struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
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struct inode *inode = d_inode(dentry);
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int status;
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if (S_ISDIR(inode->i_mode)) {
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switch(type) {
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case ACL_TYPE_ACCESS:
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alloc = get_inode_acl(inode, ACL_TYPE_DEFAULT);
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if (IS_ERR(alloc))
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goto fail;
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dfacl = alloc;
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break;
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case ACL_TYPE_DEFAULT:
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alloc = get_inode_acl(inode, ACL_TYPE_ACCESS);
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if (IS_ERR(alloc))
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goto fail;
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dfacl = acl;
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acl = alloc;
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break;
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}
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}
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if (acl == NULL) {
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alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
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if (IS_ERR(alloc))
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goto fail;
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acl = alloc;
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}
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status = __nfs3_proc_setacls(inode, acl, dfacl);
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out:
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if (acl != orig)
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posix_acl_release(acl);
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if (dfacl != orig)
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posix_acl_release(dfacl);
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return status;
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fail:
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status = PTR_ERR(alloc);
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goto out;
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}
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const struct xattr_handler *nfs3_xattr_handlers[] = {
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&posix_acl_access_xattr_handler,
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&posix_acl_default_xattr_handler,
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NULL,
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};
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static int
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nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data,
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size_t size, ssize_t *result)
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{
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struct posix_acl *acl;
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char *p = data + *result;
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acl = get_inode_acl(inode, type);
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if (IS_ERR_OR_NULL(acl))
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return 0;
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posix_acl_release(acl);
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*result += strlen(name);
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*result += 1;
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if (!size)
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return 0;
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if (*result > size)
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return -ERANGE;
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strcpy(p, name);
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return 0;
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}
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ssize_t
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nfs3_listxattr(struct dentry *dentry, char *data, size_t size)
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{
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struct inode *inode = d_inode(dentry);
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ssize_t result = 0;
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int error;
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error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS,
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XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result);
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if (error)
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return error;
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error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT,
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XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result);
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if (error)
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return error;
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return result;
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}
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