linux/fs/afs/inode.c
David Howells 68251f0a68 afs: Fix whole-volume callback handling
It's possible for an AFS file server to issue a whole-volume notification
that callbacks on all the vnodes in the file have been broken.  This is
done for R/O and backup volumes (which don't have per-file callbacks) and
for things like a volume being taken offline.

Fix callback handling to detect whole-volume notifications, to track it
across operations and to check it during inode validation.

Fixes: c435ee3455 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-14 15:15:18 +01:00

596 lines
15 KiB
C

/*
* Copyright (c) 2002 Red Hat, Inc. All rights reserved.
*
* This software may be freely redistributed under the terms of the
* GNU General Public License.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Authors: David Woodhouse <dwmw2@infradead.org>
* David Howells <dhowells@redhat.com>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/iversion.h>
#include "internal.h"
static const struct inode_operations afs_symlink_inode_operations = {
.get_link = page_get_link,
.listxattr = afs_listxattr,
};
/*
* Initialise an inode from the vnode status.
*/
static int afs_inode_init_from_status(struct afs_vnode *vnode, struct key *key)
{
struct inode *inode = AFS_VNODE_TO_I(vnode);
_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
vnode->status.type,
vnode->status.nlink,
(unsigned long long) vnode->status.size,
vnode->status.data_version,
vnode->status.mode);
read_seqlock_excl(&vnode->cb_lock);
afs_update_inode_from_status(vnode, &vnode->status, NULL,
AFS_VNODE_NOT_YET_SET);
switch (vnode->status.type) {
case AFS_FTYPE_FILE:
inode->i_mode = S_IFREG | vnode->status.mode;
inode->i_op = &afs_file_inode_operations;
inode->i_fop = &afs_file_operations;
inode->i_mapping->a_ops = &afs_fs_aops;
break;
case AFS_FTYPE_DIR:
inode->i_mode = S_IFDIR | vnode->status.mode;
inode->i_op = &afs_dir_inode_operations;
inode->i_fop = &afs_dir_file_operations;
inode->i_mapping->a_ops = &afs_dir_aops;
break;
case AFS_FTYPE_SYMLINK:
/* Symlinks with a mode of 0644 are actually mountpoints. */
if ((vnode->status.mode & 0777) == 0644) {
inode->i_flags |= S_AUTOMOUNT;
set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
inode->i_mode = S_IFDIR | 0555;
inode->i_op = &afs_mntpt_inode_operations;
inode->i_fop = &afs_mntpt_file_operations;
inode->i_mapping->a_ops = &afs_fs_aops;
} else {
inode->i_mode = S_IFLNK | vnode->status.mode;
inode->i_op = &afs_symlink_inode_operations;
inode->i_mapping->a_ops = &afs_fs_aops;
}
inode_nohighmem(inode);
break;
default:
printk("kAFS: AFS vnode with undefined type\n");
read_sequnlock_excl(&vnode->cb_lock);
return afs_protocol_error(NULL, -EBADMSG);
}
inode->i_blocks = 0;
vnode->invalid_before = vnode->status.data_version;
read_sequnlock_excl(&vnode->cb_lock);
return 0;
}
/*
* Fetch file status from the volume.
*/
int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool new_inode)
{
struct afs_fs_cursor fc;
int ret;
_enter("%s,{%x:%u.%u,S=%lx}",
vnode->volume->name,
vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
vnode->flags);
ret = -ERESTARTSYS;
if (afs_begin_vnode_operation(&fc, vnode, key)) {
while (afs_select_fileserver(&fc)) {
fc.cb_break = afs_calc_vnode_cb_break(vnode);
afs_fs_fetch_file_status(&fc, NULL, new_inode);
}
afs_check_for_remote_deletion(&fc, fc.vnode);
afs_vnode_commit_status(&fc, vnode, fc.cb_break);
ret = afs_end_vnode_operation(&fc);
}
_leave(" = %d", ret);
return ret;
}
/*
* iget5() comparator
*/
int afs_iget5_test(struct inode *inode, void *opaque)
{
struct afs_iget_data *data = opaque;
return inode->i_ino == data->fid.vnode &&
inode->i_generation == data->fid.unique;
}
/*
* iget5() comparator for inode created by autocell operations
*
* These pseudo inodes don't match anything.
*/
static int afs_iget5_pseudo_dir_test(struct inode *inode, void *opaque)
{
return 0;
}
/*
* iget5() inode initialiser
*/
static int afs_iget5_set(struct inode *inode, void *opaque)
{
struct afs_iget_data *data = opaque;
struct afs_vnode *vnode = AFS_FS_I(inode);
inode->i_ino = data->fid.vnode;
inode->i_generation = data->fid.unique;
vnode->fid = data->fid;
vnode->volume = data->volume;
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_iget_data data;
struct afs_super_info *as;
struct afs_vnode *vnode;
struct inode *inode;
static atomic_t afs_autocell_ino;
_enter("");
as = sb->s_fs_info;
if (as->volume) {
data.volume = as->volume;
data.fid.vid = as->volume->vid;
}
if (root) {
data.fid.vnode = 1;
data.fid.unique = 1;
} else {
data.fid.vnode = atomic_inc_return(&afs_autocell_ino);
data.fid.unique = 0;
}
inode = iget5_locked(sb, data.fid.vnode,
afs_iget5_pseudo_dir_test, afs_iget5_set,
&data);
if (!inode) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
inode, inode->i_ino, data.fid.vid, data.fid.vnode,
data.fid.unique);
vnode = AFS_FS_I(inode);
/* there shouldn't be an existing inode */
BUG_ON(!(inode->i_state & I_NEW));
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 = &afs_dynroot_file_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.tv_sec = get_seconds();
inode->i_ctime.tv_nsec = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime;
inode->i_blocks = 0;
inode_set_iversion_raw(inode, 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;
}
/*
* Get a cache cookie for an inode.
*/
static void afs_get_inode_cache(struct afs_vnode *vnode)
{
#ifdef CONFIG_AFS_FSCACHE
struct {
u32 vnode_id;
u32 unique;
u32 vnode_id_ext[2]; /* Allow for a 96-bit key */
} __packed key;
struct afs_vnode_cache_aux aux;
if (vnode->status.type == AFS_FTYPE_DIR) {
vnode->cache = NULL;
return;
}
key.vnode_id = vnode->fid.vnode;
key.unique = vnode->fid.unique;
key.vnode_id_ext[0] = 0;
key.vnode_id_ext[1] = 0;
aux.data_version = vnode->status.data_version;
vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
&afs_vnode_cache_index_def,
&key, sizeof(key),
&aux, sizeof(aux),
vnode, vnode->status.size, true);
#endif
}
/*
* inode retrieval
*/
struct inode *afs_iget(struct super_block *sb, struct key *key,
struct afs_fid *fid, struct afs_file_status *status,
struct afs_callback *cb, struct afs_cb_interest *cbi)
{
struct afs_iget_data data = { .fid = *fid };
struct afs_super_info *as;
struct afs_vnode *vnode;
struct inode *inode;
int ret;
_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
as = sb->s_fs_info;
data.volume = as->volume;
inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
&data);
if (!inode) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
inode, fid->vid, fid->vnode, fid->unique);
vnode = AFS_FS_I(inode);
/* deal with an existing inode */
if (!(inode->i_state & I_NEW)) {
_leave(" = %p", inode);
return inode;
}
if (!status) {
/* it's a remotely extant inode */
ret = afs_fetch_status(vnode, key, true);
if (ret < 0)
goto bad_inode;
} else {
/* it's an inode we just created */
memcpy(&vnode->status, status, sizeof(vnode->status));
if (!cb) {
/* it's a symlink we just created (the fileserver
* didn't give us a callback) */
vnode->cb_version = 0;
vnode->cb_type = 0;
vnode->cb_expires_at = 0;
} else {
vnode->cb_version = cb->version;
vnode->cb_type = cb->type;
vnode->cb_expires_at = cb->expiry;
vnode->cb_interest = afs_get_cb_interest(cbi);
set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
}
vnode->cb_expires_at += ktime_get_real_seconds();
}
ret = afs_inode_init_from_status(vnode, key);
if (ret < 0)
goto bad_inode;
afs_get_inode_cache(vnode);
/* success */
clear_bit(AFS_VNODE_UNSET, &vnode->flags);
inode->i_flags |= S_NOATIME;
unlock_new_inode(inode);
_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
return inode;
/* failure */
bad_inode:
iget_failed(inode);
_leave(" = %d [bad]", ret);
return ERR_PTR(ret);
}
/*
* mark the data attached to an inode as obsolete due to a write on the server
* - might also want to ditch all the outstanding writes and dirty pages
*/
void afs_zap_data(struct afs_vnode *vnode)
{
_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
#ifdef CONFIG_AFS_FSCACHE
fscache_invalidate(vnode->cache);
#endif
/* nuke all the non-dirty pages that aren't locked, mapped or being
* written back in a regular file and completely discard the pages in a
* directory or symlink */
if (S_ISREG(vnode->vfs_inode.i_mode))
invalidate_remote_inode(&vnode->vfs_inode);
else
invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
}
/*
* validate a vnode/inode
* - there are several things we need to check
* - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
* symlink)
* - parent dir metadata changed (security changes)
* - dentry data changed (write, truncate)
* - dentry metadata changed (security changes)
*/
int afs_validate(struct afs_vnode *vnode, struct key *key)
{
time64_t now = ktime_get_real_seconds();
bool valid = false;
int ret;
_enter("{v={%x:%u} fl=%lx},%x",
vnode->fid.vid, vnode->fid.vnode, vnode->flags,
key_serial(key));
/* Quickly check the callback state. Ideally, we'd use read_seqbegin
* here, but we have no way to pass the net namespace to the RCU
* cleanup for the server record.
*/
read_seqlock_excl(&vnode->cb_lock);
if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
if (vnode->cb_s_break != vnode->cb_interest->server->cb_s_break ||
vnode->cb_v_break != vnode->volume->cb_v_break) {
vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
vnode->cb_v_break = vnode->volume->cb_v_break;
valid = false;
} else if (vnode->status.type == AFS_FTYPE_DIR &&
test_bit(AFS_VNODE_DIR_VALID, &vnode->flags) &&
vnode->cb_expires_at - 10 > now) {
valid = true;
} else if (!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) &&
vnode->cb_expires_at - 10 > now) {
valid = true;
}
} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
valid = true;
}
read_sequnlock_excl(&vnode->cb_lock);
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
clear_nlink(&vnode->vfs_inode);
if (valid)
goto valid;
down_write(&vnode->validate_lock);
/* if the promise has expired, we need to check the server again to get
* a new promise - note that if the (parent) directory's metadata was
* changed then the security may be different and we may no longer have
* access */
if (!test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
_debug("not promised");
ret = afs_fetch_status(vnode, key, false);
if (ret < 0) {
if (ret == -ENOENT) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
ret = -ESTALE;
}
goto error_unlock;
}
_debug("new promise [fl=%lx]", vnode->flags);
}
if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
_debug("file already deleted");
ret = -ESTALE;
goto error_unlock;
}
/* if the vnode's data version number changed then its contents are
* different */
if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
afs_zap_data(vnode);
up_write(&vnode->validate_lock);
valid:
_leave(" = 0");
return 0;
error_unlock:
up_write(&vnode->validate_lock);
_leave(" = %d", ret);
return ret;
}
/*
* read the attributes of an inode
*/
int afs_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
struct afs_vnode *vnode = AFS_FS_I(inode);
int seq = 0;
_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
do {
read_seqbegin_or_lock(&vnode->cb_lock, &seq);
generic_fillattr(inode, stat);
} while (need_seqretry(&vnode->cb_lock, seq));
done_seqretry(&vnode->cb_lock, seq);
return 0;
}
/*
* discard an AFS inode
*/
int afs_drop_inode(struct inode *inode)
{
_enter("");
if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
return generic_delete_inode(inode);
else
return generic_drop_inode(inode);
}
/*
* clear an AFS inode
*/
void afs_evict_inode(struct inode *inode)
{
struct afs_vnode *vnode;
vnode = AFS_FS_I(inode);
_enter("{%x:%u.%d}",
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique);
_debug("CLEAR INODE %p", inode);
ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (vnode->cb_interest) {
afs_put_cb_interest(afs_i2net(inode), vnode->cb_interest);
vnode->cb_interest = NULL;
}
while (!list_empty(&vnode->wb_keys)) {
struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
struct afs_wb_key, vnode_link);
list_del(&wbk->vnode_link);
afs_put_wb_key(wbk);
}
#ifdef CONFIG_AFS_FSCACHE
{
struct afs_vnode_cache_aux aux;
aux.data_version = vnode->status.data_version;
fscache_relinquish_cookie(vnode->cache, &aux,
test_bit(AFS_VNODE_DELETED, &vnode->flags));
vnode->cache = NULL;
}
#endif
afs_put_permits(rcu_access_pointer(vnode->permit_cache));
_leave("");
}
/*
* set the attributes of an inode
*/
int afs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct afs_fs_cursor fc;
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
struct key *key;
int ret;
_enter("{%x:%u},{n=%pd},%x",
vnode->fid.vid, vnode->fid.vnode, dentry,
attr->ia_valid);
if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
ATTR_MTIME))) {
_leave(" = 0 [unsupported]");
return 0;
}
/* flush any dirty data outstanding on a regular file */
if (S_ISREG(vnode->vfs_inode.i_mode))
filemap_write_and_wait(vnode->vfs_inode.i_mapping);
if (attr->ia_valid & ATTR_FILE) {
key = afs_file_key(attr->ia_file);
} else {
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key)) {
ret = PTR_ERR(key);
goto error;
}
}
ret = -ERESTARTSYS;
if (afs_begin_vnode_operation(&fc, vnode, key)) {
while (afs_select_fileserver(&fc)) {
fc.cb_break = afs_calc_vnode_cb_break(vnode);
afs_fs_setattr(&fc, attr);
}
afs_check_for_remote_deletion(&fc, fc.vnode);
afs_vnode_commit_status(&fc, vnode, fc.cb_break);
ret = afs_end_vnode_operation(&fc);
}
if (!(attr->ia_valid & ATTR_FILE))
key_put(key);
error:
_leave(" = %d", ret);
return ret;
}