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21fc61c73c
kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system. new helper (inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
500 lines
12 KiB
C
500 lines
12 KiB
C
/*
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* Copyright (c) 2002 Red Hat, Inc. All rights reserved.
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*
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* This software may be freely redistributed under the terms of the
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* GNU General Public License.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Authors: David Woodhouse <dwmw2@infradead.org>
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* David Howells <dhowells@redhat.com>
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*
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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/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include "internal.h"
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struct afs_iget_data {
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struct afs_fid fid;
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struct afs_volume *volume; /* volume on which resides */
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};
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/*
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* map the AFS file status to the inode member variables
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*/
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static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
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{
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struct inode *inode = AFS_VNODE_TO_I(vnode);
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_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
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vnode->status.type,
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vnode->status.nlink,
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(unsigned long long) vnode->status.size,
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vnode->status.data_version,
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vnode->status.mode);
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switch (vnode->status.type) {
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case AFS_FTYPE_FILE:
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inode->i_mode = S_IFREG | vnode->status.mode;
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inode->i_op = &afs_file_inode_operations;
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inode->i_fop = &afs_file_operations;
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break;
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case AFS_FTYPE_DIR:
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inode->i_mode = S_IFDIR | vnode->status.mode;
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inode->i_op = &afs_dir_inode_operations;
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inode->i_fop = &afs_dir_file_operations;
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break;
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case AFS_FTYPE_SYMLINK:
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inode->i_mode = S_IFLNK | vnode->status.mode;
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inode->i_op = &page_symlink_inode_operations;
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inode_nohighmem(inode);
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break;
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default:
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printk("kAFS: AFS vnode with undefined type\n");
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return -EBADMSG;
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}
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#ifdef CONFIG_AFS_FSCACHE
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if (vnode->status.size != inode->i_size)
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fscache_attr_changed(vnode->cache);
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#endif
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set_nlink(inode, vnode->status.nlink);
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inode->i_uid = vnode->status.owner;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_size = vnode->status.size;
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inode->i_ctime.tv_sec = vnode->status.mtime_server;
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode->i_generation = vnode->fid.unique;
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inode->i_version = vnode->status.data_version;
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inode->i_mapping->a_ops = &afs_fs_aops;
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/* check to see whether a symbolic link is really a mountpoint */
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if (vnode->status.type == AFS_FTYPE_SYMLINK) {
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afs_mntpt_check_symlink(vnode, key);
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if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
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inode->i_mode = S_IFDIR | vnode->status.mode;
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inode->i_op = &afs_mntpt_inode_operations;
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inode->i_fop = &afs_mntpt_file_operations;
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}
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}
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return 0;
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}
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/*
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* iget5() comparator
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*/
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static int afs_iget5_test(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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return inode->i_ino == data->fid.vnode &&
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inode->i_generation == data->fid.unique;
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}
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/*
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* iget5() comparator for inode created by autocell operations
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*
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* These pseudo inodes don't match anything.
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*/
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static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
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{
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return 0;
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}
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/*
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* iget5() inode initialiser
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*/
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static int afs_iget5_set(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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inode->i_ino = data->fid.vnode;
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inode->i_generation = data->fid.unique;
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vnode->fid = data->fid;
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vnode->volume = data->volume;
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return 0;
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}
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/*
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* inode retrieval for autocell
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*/
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struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
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int namesz, struct key *key)
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{
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struct afs_iget_data data;
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct super_block *sb;
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struct inode *inode;
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static atomic_t afs_autocell_ino;
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_enter("{%x:%u},%*.*s,",
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AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
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namesz, namesz, dev_name ?: "");
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sb = dir->i_sb;
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as = sb->s_fs_info;
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data.volume = as->volume;
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data.fid.vid = as->volume->vid;
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data.fid.unique = 0;
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data.fid.vnode = 0;
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inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
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afs_iget5_autocell_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
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inode, inode->i_ino, data.fid.vid, data.fid.vnode,
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data.fid.unique);
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vnode = AFS_FS_I(inode);
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/* there shouldn't be an existing inode */
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BUG_ON(!(inode->i_state & I_NEW));
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inode->i_size = 0;
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inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
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inode->i_op = &afs_autocell_inode_operations;
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set_nlink(inode, 2);
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_ctime.tv_sec = get_seconds();
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode->i_version = 0;
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inode->i_generation = 0;
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set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
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set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
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inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p", inode);
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return inode;
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}
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/*
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* inode retrieval
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*/
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struct inode *afs_iget(struct super_block *sb, struct key *key,
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struct afs_fid *fid, struct afs_file_status *status,
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struct afs_callback *cb)
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{
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struct afs_iget_data data = { .fid = *fid };
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct inode *inode;
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int ret;
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_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
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as = sb->s_fs_info;
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data.volume = as->volume;
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inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
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inode, fid->vid, fid->vnode, fid->unique);
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vnode = AFS_FS_I(inode);
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/* deal with an existing inode */
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if (!(inode->i_state & I_NEW)) {
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_leave(" = %p", inode);
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return inode;
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}
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if (!status) {
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/* it's a remotely extant inode */
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set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
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ret = afs_vnode_fetch_status(vnode, NULL, key);
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if (ret < 0)
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goto bad_inode;
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} else {
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/* it's an inode we just created */
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memcpy(&vnode->status, status, sizeof(vnode->status));
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if (!cb) {
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/* it's a symlink we just created (the fileserver
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* didn't give us a callback) */
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vnode->cb_version = 0;
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vnode->cb_expiry = 0;
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vnode->cb_type = 0;
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vnode->cb_expires = get_seconds();
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} else {
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vnode->cb_version = cb->version;
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vnode->cb_expiry = cb->expiry;
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vnode->cb_type = cb->type;
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vnode->cb_expires = vnode->cb_expiry + get_seconds();
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}
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}
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/* set up caching before mapping the status, as map-status reads the
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* first page of symlinks to see if they're really mountpoints */
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inode->i_size = vnode->status.size;
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#ifdef CONFIG_AFS_FSCACHE
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vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
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&afs_vnode_cache_index_def,
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vnode, true);
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#endif
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ret = afs_inode_map_status(vnode, key);
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if (ret < 0)
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goto bad_inode;
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/* success */
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clear_bit(AFS_VNODE_UNSET, &vnode->flags);
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inode->i_flags |= S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
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return inode;
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/* failure */
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bad_inode:
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vnode->cache, 0);
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vnode->cache = NULL;
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#endif
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iget_failed(inode);
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_leave(" = %d [bad]", ret);
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return ERR_PTR(ret);
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}
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/*
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* mark the data attached to an inode as obsolete due to a write on the server
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* - might also want to ditch all the outstanding writes and dirty pages
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*/
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void afs_zap_data(struct afs_vnode *vnode)
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{
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_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
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/* nuke all the non-dirty pages that aren't locked, mapped or being
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* written back in a regular file and completely discard the pages in a
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* directory or symlink */
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if (S_ISREG(vnode->vfs_inode.i_mode))
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invalidate_remote_inode(&vnode->vfs_inode);
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else
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invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
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}
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/*
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* validate a vnode/inode
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* - there are several things we need to check
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* - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
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* symlink)
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* - parent dir metadata changed (security changes)
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* - dentry data changed (write, truncate)
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* - dentry metadata changed (security changes)
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*/
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int afs_validate(struct afs_vnode *vnode, struct key *key)
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{
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int ret;
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_enter("{v={%x:%u} fl=%lx},%x",
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vnode->fid.vid, vnode->fid.vnode, vnode->flags,
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key_serial(key));
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if (vnode->cb_promised &&
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!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
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!test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
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!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
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if (vnode->cb_expires < get_seconds() + 10) {
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_debug("callback expired");
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set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
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} else {
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goto valid;
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}
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}
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
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goto valid;
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mutex_lock(&vnode->validate_lock);
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/* if the promise has expired, we need to check the server again to get
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* a new promise - note that if the (parent) directory's metadata was
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* changed then the security may be different and we may no longer have
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* access */
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if (!vnode->cb_promised ||
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test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
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_debug("not promised");
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ret = afs_vnode_fetch_status(vnode, NULL, key);
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if (ret < 0)
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goto error_unlock;
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_debug("new promise [fl=%lx]", vnode->flags);
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}
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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_debug("file already deleted");
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ret = -ESTALE;
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goto error_unlock;
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}
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/* if the vnode's data version number changed then its contents are
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* different */
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if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
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afs_zap_data(vnode);
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clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
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mutex_unlock(&vnode->validate_lock);
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valid:
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_leave(" = 0");
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return 0;
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error_unlock:
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mutex_unlock(&vnode->validate_lock);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* read the attributes of an inode
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*/
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int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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struct inode *inode;
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inode = d_inode(dentry);
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_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
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generic_fillattr(inode, stat);
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return 0;
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}
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/*
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* discard an AFS inode
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*/
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int afs_drop_inode(struct inode *inode)
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{
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_enter("");
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if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
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return generic_delete_inode(inode);
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else
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return generic_drop_inode(inode);
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}
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/*
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* clear an AFS inode
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*/
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void afs_evict_inode(struct inode *inode)
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{
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struct afs_permits *permits;
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struct afs_vnode *vnode;
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vnode = AFS_FS_I(inode);
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_enter("{%x:%u.%d} v=%u x=%u t=%u }",
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vnode->fid.vid,
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vnode->fid.vnode,
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vnode->fid.unique,
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vnode->cb_version,
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vnode->cb_expiry,
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vnode->cb_type);
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_debug("CLEAR INODE %p", inode);
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ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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afs_give_up_callback(vnode);
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if (vnode->server) {
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spin_lock(&vnode->server->fs_lock);
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rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
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spin_unlock(&vnode->server->fs_lock);
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afs_put_server(vnode->server);
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vnode->server = NULL;
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}
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ASSERT(list_empty(&vnode->writebacks));
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ASSERT(!vnode->cb_promised);
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vnode->cache, 0);
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vnode->cache = NULL;
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#endif
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mutex_lock(&vnode->permits_lock);
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permits = vnode->permits;
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rcu_assign_pointer(vnode->permits, NULL);
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mutex_unlock(&vnode->permits_lock);
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if (permits)
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call_rcu(&permits->rcu, afs_zap_permits);
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_leave("");
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}
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/*
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* set the attributes of an inode
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*/
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int afs_setattr(struct dentry *dentry, struct iattr *attr)
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{
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struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
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struct key *key;
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int ret;
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_enter("{%x:%u},{n=%pd},%x",
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vnode->fid.vid, vnode->fid.vnode, dentry,
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attr->ia_valid);
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if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
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ATTR_MTIME))) {
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_leave(" = 0 [unsupported]");
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return 0;
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}
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/* flush any dirty data outstanding on a regular file */
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if (S_ISREG(vnode->vfs_inode.i_mode)) {
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filemap_write_and_wait(vnode->vfs_inode.i_mapping);
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afs_writeback_all(vnode);
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}
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if (attr->ia_valid & ATTR_FILE) {
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key = attr->ia_file->private_data;
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} else {
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error;
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}
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}
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|
|
ret = afs_vnode_setattr(vnode, key, attr);
|
|
if (!(attr->ia_valid & ATTR_FILE))
|
|
key_put(key);
|
|
|
|
error:
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|