linux/fs/afs/inode.c
David Howells ec0fa0b659 afs: Fix deadlock between writeback and truncate
The afs filesystem has a lock[*] that it uses to serialise I/O operations
going to the server (vnode->io_lock), as the server will only perform one
modification operation at a time on any given file or directory.  This
prevents the the filesystem from filling up all the call slots to a server
with calls that aren't going to be executed in parallel anyway, thereby
allowing operations on other files to obtain slots.

  [*] Note that is probably redundant for directories at least since
      i_rwsem is used to serialise directory modifications and
      lookup/reading vs modification.  The server does allow parallel
      non-modification ops, however.

When a file truncation op completes, we truncate the in-memory copy of the
file to match - but we do it whilst still holding the io_lock, the idea
being to prevent races with other operations.

However, if writeback starts in a worker thread simultaneously with
truncation (whilst notify_change() is called with i_rwsem locked, writeback
pays it no heed), it may manage to set PG_writeback bits on the pages that
will get truncated before afs_setattr_success() manages to call
truncate_pagecache().  Truncate will then wait for those pages - whilst
still inside io_lock:

    # cat /proc/8837/stack
    [<0>] wait_on_page_bit_common+0x184/0x1e7
    [<0>] truncate_inode_pages_range+0x37f/0x3eb
    [<0>] truncate_pagecache+0x3c/0x53
    [<0>] afs_setattr_success+0x4d/0x6e
    [<0>] afs_wait_for_operation+0xd8/0x169
    [<0>] afs_do_sync_operation+0x16/0x1f
    [<0>] afs_setattr+0x1fb/0x25d
    [<0>] notify_change+0x2cf/0x3c4
    [<0>] do_truncate+0x7f/0xb2
    [<0>] do_sys_ftruncate+0xd1/0x104
    [<0>] do_syscall_64+0x2d/0x3a
    [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

The writeback operation, however, stalls indefinitely because it needs to
get the io_lock to proceed:

    # cat /proc/5940/stack
    [<0>] afs_get_io_locks+0x58/0x1ae
    [<0>] afs_begin_vnode_operation+0xc7/0xd1
    [<0>] afs_store_data+0x1b2/0x2a3
    [<0>] afs_write_back_from_locked_page+0x418/0x57c
    [<0>] afs_writepages_region+0x196/0x224
    [<0>] afs_writepages+0x74/0x156
    [<0>] do_writepages+0x2d/0x56
    [<0>] __writeback_single_inode+0x84/0x207
    [<0>] writeback_sb_inodes+0x238/0x3cf
    [<0>] __writeback_inodes_wb+0x68/0x9f
    [<0>] wb_writeback+0x145/0x26c
    [<0>] wb_do_writeback+0x16a/0x194
    [<0>] wb_workfn+0x74/0x177
    [<0>] process_one_work+0x174/0x264
    [<0>] worker_thread+0x117/0x1b9
    [<0>] kthread+0xec/0xf1
    [<0>] ret_from_fork+0x1f/0x30

and thus deadlock has occurred.

Note that whilst afs_setattr() calls filemap_write_and_wait(), the fact
that the caller is holding i_rwsem doesn't preclude more pages being
dirtied through an mmap'd region.

Fix this by:

 (1) Use the vnode validate_lock to mediate access between afs_setattr()
     and afs_writepages():

     (a) Exclusively lock validate_lock in afs_setattr() around the whole
     	 RPC operation.

     (b) If WB_SYNC_ALL isn't set on entry to afs_writepages(), trying to
     	 shared-lock validate_lock and returning immediately if we couldn't
     	 get it.

     (c) If WB_SYNC_ALL is set, wait for the lock.

     The validate_lock is also used to validate a file and to zap its cache
     if the file was altered by a third party, so it's probably a good fit
     for this.

 (2) Move the truncation outside of the io_lock in setattr, using the same
     hook as is used for local directory editing.

     This requires the old i_size to be retained in the operation record as
     we commit the revised status to the inode members inside the io_lock
     still, but we still need to know if we reduced the file size.

Fixes: d2ddc776a4 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-08 10:50:55 -07:00

914 lines
23 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"
#include "afs_fs.h"
static const struct inode_operations afs_symlink_inode_operations = {
.get_link = page_get_link,
.listxattr = afs_listxattr,
};
static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
{
static unsigned long once_only;
pr_warn("kAFS: AFS vnode with undefined type %u\n", vnode->status.type);
pr_warn("kAFS: A=%d m=%o s=%llx v=%llx\n",
vnode->status.abort_code,
vnode->status.mode,
vnode->status.size,
vnode->status.data_version);
pr_warn("kAFS: vnode %llx:%llx:%x\n",
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique);
if (parent_vnode)
pr_warn("kAFS: dir %llx:%llx:%x\n",
parent_vnode->fid.vid,
parent_vnode->fid.vnode,
parent_vnode->fid.unique);
if (!test_and_set_bit(0, &once_only))
dump_stack();
}
/*
* Set the file size and block count. Estimate the number of 512 bytes blocks
* used, rounded up to nearest 1K for consistency with other AFS clients.
*/
static void afs_set_i_size(struct afs_vnode *vnode, u64 size)
{
i_size_write(&vnode->vfs_inode, size);
vnode->vfs_inode.i_blocks = ((size + 1023) >> 10) << 1;
}
/*
* Initialise an inode from the vnode status.
*/
static int afs_inode_init_from_status(struct afs_operation *op,
struct afs_vnode_param *vp,
struct afs_vnode *vnode)
{
struct afs_file_status *status = &vp->scb.status;
struct inode *inode = AFS_VNODE_TO_I(vnode);
struct timespec64 t;
_enter("{%llx:%llu.%u} %s",
vp->fid.vid, vp->fid.vnode, vp->fid.unique,
op->type ? op->type->name : "???");
_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
status->type,
status->nlink,
(unsigned long long) status->size,
status->data_version,
status->mode);
write_seqlock(&vnode->cb_lock);
vnode->cb_v_break = op->cb_v_break;
vnode->cb_s_break = op->cb_s_break;
vnode->status = *status;
t = status->mtime_client;
inode->i_ctime = t;
inode->i_mtime = t;
inode->i_atime = t;
inode->i_flags |= S_NOATIME;
inode->i_uid = make_kuid(&init_user_ns, status->owner);
inode->i_gid = make_kgid(&init_user_ns, status->group);
set_nlink(&vnode->vfs_inode, status->nlink);
switch (status->type) {
case AFS_FTYPE_FILE:
inode->i_mode = S_IFREG | 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 | 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 ((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 | status->mode;
inode->i_op = &afs_symlink_inode_operations;
inode->i_mapping->a_ops = &afs_fs_aops;
}
inode_nohighmem(inode);
break;
default:
dump_vnode(vnode, op->file[0].vnode != vnode ? op->file[0].vnode : NULL);
write_sequnlock(&vnode->cb_lock);
return afs_protocol_error(NULL, afs_eproto_file_type);
}
afs_set_i_size(vnode, status->size);
vnode->invalid_before = status->data_version;
inode_set_iversion_raw(&vnode->vfs_inode, status->data_version);
if (!vp->scb.have_cb) {
/* it's a symlink we just created (the fileserver
* didn't give us a callback) */
vnode->cb_expires_at = ktime_get_real_seconds();
} else {
vnode->cb_expires_at = vp->scb.callback.expires_at;
vnode->cb_server = op->server;
set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
}
write_sequnlock(&vnode->cb_lock);
return 0;
}
/*
* Update the core inode struct from a returned status record.
*/
static void afs_apply_status(struct afs_operation *op,
struct afs_vnode_param *vp)
{
struct afs_file_status *status = &vp->scb.status;
struct afs_vnode *vnode = vp->vnode;
struct inode *inode = &vnode->vfs_inode;
struct timespec64 t;
umode_t mode;
bool data_changed = false;
bool change_size = vp->set_size;
_enter("{%llx:%llu.%u} %s",
vp->fid.vid, vp->fid.vnode, vp->fid.unique,
op->type ? op->type->name : "???");
BUG_ON(test_bit(AFS_VNODE_UNSET, &vnode->flags));
if (status->type != vnode->status.type) {
pr_warn("Vnode %llx:%llx:%x changed type %u to %u\n",
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
status->type, vnode->status.type);
afs_protocol_error(NULL, afs_eproto_bad_status);
return;
}
if (status->nlink != vnode->status.nlink)
set_nlink(inode, status->nlink);
if (status->owner != vnode->status.owner)
inode->i_uid = make_kuid(&init_user_ns, status->owner);
if (status->group != vnode->status.group)
inode->i_gid = make_kgid(&init_user_ns, status->group);
if (status->mode != vnode->status.mode) {
mode = inode->i_mode;
mode &= ~S_IALLUGO;
mode |= status->mode;
WRITE_ONCE(inode->i_mode, mode);
}
t = status->mtime_client;
inode->i_mtime = t;
if (vp->update_ctime)
inode->i_ctime = op->ctime;
if (vnode->status.data_version != status->data_version)
data_changed = true;
vnode->status = *status;
if (vp->dv_before + vp->dv_delta != status->data_version) {
if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags))
pr_warn("kAFS: vnode modified {%llx:%llu} %llx->%llx %s\n",
vnode->fid.vid, vnode->fid.vnode,
(unsigned long long)vp->dv_before + vp->dv_delta,
(unsigned long long)status->data_version,
op->type ? op->type->name : "???");
vnode->invalid_before = status->data_version;
if (vnode->status.type == AFS_FTYPE_DIR) {
if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
afs_stat_v(vnode, n_inval);
} else {
set_bit(AFS_VNODE_ZAP_DATA, &vnode->flags);
}
change_size = true;
} else if (vnode->status.type == AFS_FTYPE_DIR) {
/* Expected directory change is handled elsewhere so
* that we can locally edit the directory and save on a
* download.
*/
if (test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
data_changed = false;
change_size = true;
}
if (data_changed) {
inode_set_iversion_raw(inode, status->data_version);
/* Only update the size if the data version jumped. If the
* file is being modified locally, then we might have our own
* idea of what the size should be that's not the same as
* what's on the server.
*/
if (change_size) {
afs_set_i_size(vnode, status->size);
inode->i_ctime = t;
inode->i_atime = t;
}
}
}
/*
* Apply a callback to a vnode.
*/
static void afs_apply_callback(struct afs_operation *op,
struct afs_vnode_param *vp)
{
struct afs_callback *cb = &vp->scb.callback;
struct afs_vnode *vnode = vp->vnode;
if (!afs_cb_is_broken(vp->cb_break_before, vnode)) {
vnode->cb_expires_at = cb->expires_at;
vnode->cb_server = op->server;
set_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
}
}
/*
* Apply the received status and callback to an inode all in the same critical
* section to avoid races with afs_validate().
*/
void afs_vnode_commit_status(struct afs_operation *op, struct afs_vnode_param *vp)
{
struct afs_vnode *vnode = vp->vnode;
_enter("");
write_seqlock(&vnode->cb_lock);
if (vp->scb.have_error) {
/* A YFS server will return this from RemoveFile2 and AFS and
* YFS will return this from InlineBulkStatus.
*/
if (vp->scb.status.abort_code == VNOVNODE) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
clear_nlink(&vnode->vfs_inode);
__afs_break_callback(vnode, afs_cb_break_for_deleted);
op->flags &= ~AFS_OPERATION_DIR_CONFLICT;
}
} else if (vp->scb.have_status) {
afs_apply_status(op, vp);
if (vp->scb.have_cb)
afs_apply_callback(op, vp);
} else if (vp->op_unlinked && !(op->flags & AFS_OPERATION_DIR_CONFLICT)) {
drop_nlink(&vnode->vfs_inode);
if (vnode->vfs_inode.i_nlink == 0) {
set_bit(AFS_VNODE_DELETED, &vnode->flags);
__afs_break_callback(vnode, afs_cb_break_for_deleted);
}
}
write_sequnlock(&vnode->cb_lock);
if (vp->scb.have_status)
afs_cache_permit(vnode, op->key, vp->cb_break_before, &vp->scb);
}
static void afs_fetch_status_success(struct afs_operation *op)
{
struct afs_vnode_param *vp = &op->file[op->fetch_status.which];
struct afs_vnode *vnode = vp->vnode;
int ret;
if (vnode->vfs_inode.i_state & I_NEW) {
ret = afs_inode_init_from_status(op, vp, vnode);
op->error = ret;
if (ret == 0)
afs_cache_permit(vnode, op->key, vp->cb_break_before, &vp->scb);
} else {
afs_vnode_commit_status(op, vp);
}
}
const struct afs_operation_ops afs_fetch_status_operation = {
.issue_afs_rpc = afs_fs_fetch_status,
.issue_yfs_rpc = yfs_fs_fetch_status,
.success = afs_fetch_status_success,
.aborted = afs_check_for_remote_deletion,
};
/*
* Fetch file status from the volume.
*/
int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool is_new,
afs_access_t *_caller_access)
{
struct afs_operation *op;
_enter("%s,{%llx:%llu.%u,S=%lx}",
vnode->volume->name,
vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
vnode->flags);
op = afs_alloc_operation(key, vnode->volume);
if (IS_ERR(op))
return PTR_ERR(op);
afs_op_set_vnode(op, 0, vnode);
op->nr_files = 1;
op->ops = &afs_fetch_status_operation;
afs_begin_vnode_operation(op);
afs_wait_for_operation(op);
if (_caller_access)
*_caller_access = op->file[0].scb.status.caller_access;
return afs_put_operation(op);
}
/*
* ilookup() comparator
*/
int afs_ilookup5_test_by_fid(struct inode *inode, void *opaque)
{
struct afs_vnode *vnode = AFS_FS_I(inode);
struct afs_fid *fid = opaque;
return (fid->vnode == vnode->fid.vnode &&
fid->vnode_hi == vnode->fid.vnode_hi &&
fid->unique == vnode->fid.unique);
}
/*
* iget5() comparator
*/
static int afs_iget5_test(struct inode *inode, void *opaque)
{
struct afs_vnode_param *vp = opaque;
//struct afs_vnode *vnode = AFS_FS_I(inode);
return afs_ilookup5_test_by_fid(inode, &vp->fid);
}
/*
* iget5() inode initialiser
*/
static int afs_iget5_set(struct inode *inode, void *opaque)
{
struct afs_vnode_param *vp = opaque;
struct afs_super_info *as = AFS_FS_S(inode->i_sb);
struct afs_vnode *vnode = AFS_FS_I(inode);
vnode->volume = as->volume;
vnode->fid = vp->fid;
/* YFS supports 96-bit vnode IDs, but Linux only supports
* 64-bit inode numbers.
*/
inode->i_ino = vnode->fid.vnode;
inode->i_generation = vnode->fid.unique;
return 0;
}
/*
* 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] = vnode->fid.vnode >> 32;
key.vnode_id_ext[1] = vnode->fid.vnode_hi;
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 afs_operation *op, struct afs_vnode_param *vp)
{
struct afs_vnode_param *dvp = &op->file[0];
struct super_block *sb = dvp->vnode->vfs_inode.i_sb;
struct afs_vnode *vnode;
struct inode *inode;
int ret;
_enter(",{%llx:%llu.%u},,", vp->fid.vid, vp->fid.vnode, vp->fid.unique);
inode = iget5_locked(sb, vp->fid.vnode, afs_iget5_test, afs_iget5_set, vp);
if (!inode) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
vnode = AFS_FS_I(inode);
_debug("GOT INODE %p { vl=%llx vn=%llx, u=%x }",
inode, vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
/* deal with an existing inode */
if (!(inode->i_state & I_NEW)) {
_leave(" = %p", inode);
return inode;
}
ret = afs_inode_init_from_status(op, vp, vnode);
if (ret < 0)
goto bad_inode;
afs_get_inode_cache(vnode);
/* success */
clear_bit(AFS_VNODE_UNSET, &vnode->flags);
unlock_new_inode(inode);
_leave(" = %p", inode);
return inode;
/* failure */
bad_inode:
iget_failed(inode);
_leave(" = %d [bad]", ret);
return ERR_PTR(ret);
}
static int afs_iget5_set_root(struct inode *inode, void *opaque)
{
struct afs_super_info *as = AFS_FS_S(inode->i_sb);
struct afs_vnode *vnode = AFS_FS_I(inode);
vnode->volume = as->volume;
vnode->fid.vid = as->volume->vid,
vnode->fid.vnode = 1;
vnode->fid.unique = 1;
inode->i_ino = 1;
inode->i_generation = 1;
return 0;
}
/*
* Set up the root inode for a volume. This is always vnode 1, unique 1 within
* the volume.
*/
struct inode *afs_root_iget(struct super_block *sb, struct key *key)
{
struct afs_super_info *as = AFS_FS_S(sb);
struct afs_operation *op;
struct afs_vnode *vnode;
struct inode *inode;
int ret;
_enter(",{%llx},,", as->volume->vid);
inode = iget5_locked(sb, 1, NULL, afs_iget5_set_root, NULL);
if (!inode) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
_debug("GOT ROOT INODE %p { vl=%llx }", inode, as->volume->vid);
BUG_ON(!(inode->i_state & I_NEW));
vnode = AFS_FS_I(inode);
vnode->cb_v_break = as->volume->cb_v_break,
op = afs_alloc_operation(key, as->volume);
if (IS_ERR(op)) {
ret = PTR_ERR(op);
goto error;
}
afs_op_set_vnode(op, 0, vnode);
op->nr_files = 1;
op->ops = &afs_fetch_status_operation;
ret = afs_do_sync_operation(op);
if (ret < 0)
goto error;
afs_get_inode_cache(vnode);
clear_bit(AFS_VNODE_UNSET, &vnode->flags);
unlock_new_inode(inode);
_leave(" = %p", inode);
return inode;
error:
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
*/
static void afs_zap_data(struct afs_vnode *vnode)
{
_enter("{%llx:%llu}", 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);
}
/*
* Get the server reinit counter for a vnode's current server.
*/
static bool afs_get_s_break_rcu(struct afs_vnode *vnode, unsigned int *_s_break)
{
struct afs_server_list *slist = rcu_dereference(vnode->volume->servers);
struct afs_server *server;
int i;
for (i = 0; i < slist->nr_servers; i++) {
server = slist->servers[i].server;
if (server == vnode->cb_server) {
*_s_break = READ_ONCE(server->cb_s_break);
return true;
}
}
return false;
}
/*
* Check the validity of a vnode/inode.
*/
bool afs_check_validity(struct afs_vnode *vnode)
{
struct afs_volume *volume = vnode->volume;
enum afs_cb_break_reason need_clear = afs_cb_break_no_break;
time64_t now = ktime_get_real_seconds();
bool valid;
unsigned int cb_break, cb_s_break, cb_v_break;
int seq = 0;
do {
read_seqbegin_or_lock(&vnode->cb_lock, &seq);
cb_v_break = READ_ONCE(volume->cb_v_break);
cb_break = vnode->cb_break;
if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
afs_get_s_break_rcu(vnode, &cb_s_break)) {
if (vnode->cb_s_break != cb_s_break ||
vnode->cb_v_break != cb_v_break) {
vnode->cb_s_break = cb_s_break;
vnode->cb_v_break = cb_v_break;
need_clear = afs_cb_break_for_vsbreak;
valid = false;
} else if (test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
need_clear = afs_cb_break_for_zap;
valid = false;
} else if (vnode->cb_expires_at - 10 <= now) {
need_clear = afs_cb_break_for_lapsed;
valid = false;
} else {
valid = true;
}
} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
valid = true;
} else {
vnode->cb_v_break = cb_v_break;
valid = false;
}
} while (need_seqretry(&vnode->cb_lock, seq));
done_seqretry(&vnode->cb_lock, seq);
if (need_clear != afs_cb_break_no_break) {
write_seqlock(&vnode->cb_lock);
if (cb_break == vnode->cb_break)
__afs_break_callback(vnode, need_clear);
else
trace_afs_cb_miss(&vnode->fid, need_clear);
write_sequnlock(&vnode->cb_lock);
valid = false;
}
return valid;
}
/*
* 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)
{
bool valid;
int ret;
_enter("{v={%llx:%llu} fl=%lx},%x",
vnode->fid.vid, vnode->fid.vnode, vnode->flags,
key_serial(key));
rcu_read_lock();
valid = afs_check_validity(vnode);
rcu_read_unlock();
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, NULL);
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);
if (test_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags) &&
stat->nlink > 0)
stat->nlink -= 1;
} 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("{%llx:%llu.%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);
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_prune_wb_keys(vnode);
afs_put_permits(rcu_access_pointer(vnode->permit_cache));
key_put(vnode->silly_key);
vnode->silly_key = NULL;
key_put(vnode->lock_key);
vnode->lock_key = NULL;
_leave("");
}
static void afs_setattr_success(struct afs_operation *op)
{
struct afs_vnode_param *vp = &op->file[0];
struct inode *inode = &vp->vnode->vfs_inode;
loff_t old_i_size = i_size_read(inode);
op->setattr.old_i_size = old_i_size;
afs_vnode_commit_status(op, vp);
/* inode->i_size has now been changed. */
if (op->setattr.attr->ia_valid & ATTR_SIZE) {
loff_t size = op->setattr.attr->ia_size;
if (size > old_i_size)
pagecache_isize_extended(inode, old_i_size, size);
}
}
static void afs_setattr_edit_file(struct afs_operation *op)
{
struct afs_vnode_param *vp = &op->file[0];
struct inode *inode = &vp->vnode->vfs_inode;
if (op->setattr.attr->ia_valid & ATTR_SIZE) {
loff_t size = op->setattr.attr->ia_size;
loff_t i_size = op->setattr.old_i_size;
if (size < i_size)
truncate_pagecache(inode, size);
}
}
static const struct afs_operation_ops afs_setattr_operation = {
.issue_afs_rpc = afs_fs_setattr,
.issue_yfs_rpc = yfs_fs_setattr,
.success = afs_setattr_success,
.edit_dir = afs_setattr_edit_file,
};
/*
* set the attributes of an inode
*/
int afs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct afs_operation *op;
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
int ret;
_enter("{%llx:%llu},{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 | ATTR_MTIME_SET | ATTR_TIMES_SET |
ATTR_TOUCH))) {
_leave(" = 0 [unsupported]");
return 0;
}
if (attr->ia_valid & ATTR_SIZE) {
if (!S_ISREG(vnode->vfs_inode.i_mode))
return -EISDIR;
ret = inode_newsize_ok(&vnode->vfs_inode, attr->ia_size);
if (ret)
return ret;
if (attr->ia_size == i_size_read(&vnode->vfs_inode))
attr->ia_valid &= ~ATTR_SIZE;
}
/* 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);
/* Prevent any new writebacks from starting whilst we do this. */
down_write(&vnode->validate_lock);
op = afs_alloc_operation(((attr->ia_valid & ATTR_FILE) ?
afs_file_key(attr->ia_file) : NULL),
vnode->volume);
if (IS_ERR(op)) {
ret = PTR_ERR(op);
goto out_unlock;
}
afs_op_set_vnode(op, 0, vnode);
op->setattr.attr = attr;
if (attr->ia_valid & ATTR_SIZE) {
op->file[0].dv_delta = 1;
op->file[0].set_size = true;
}
op->ctime = attr->ia_ctime;
op->file[0].update_ctime = 1;
op->ops = &afs_setattr_operation;
ret = afs_do_sync_operation(op);
out_unlock:
up_write(&vnode->validate_lock);
_leave(" = %d", ret);
return ret;
}