/usr/src/aufs-4.9+20161219/fs/aufs/hnotify.c is in aufs-dkms 4.9+20161219-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* Copyright (C) 2005-2016 Junjiro R. Okajima
*
* This program, aufs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* abstraction to notify the direct changes on lower directories
*/
#include "aufs.h"
int au_hn_alloc(struct au_hinode *hinode, struct inode *inode)
{
int err;
struct au_hnotify *hn;
err = -ENOMEM;
hn = au_cache_alloc_hnotify();
if (hn) {
hn->hn_aufs_inode = inode;
hinode->hi_notify = hn;
err = au_hnotify_op.alloc(hinode);
AuTraceErr(err);
if (unlikely(err)) {
hinode->hi_notify = NULL;
au_cache_dfree_hnotify(hn);
/*
* The upper dir was removed by udba, but the same named
* dir left. In this case, aufs assignes a new inode
* number and set the monitor again.
* For the lower dir, the old monitnor is still left.
*/
if (err == -EEXIST)
err = 0;
}
}
AuTraceErr(err);
return err;
}
void au_hn_free(struct au_hinode *hinode)
{
struct au_hnotify *hn;
hn = hinode->hi_notify;
if (hn) {
hinode->hi_notify = NULL;
if (au_hnotify_op.free(hinode, hn))
au_cache_dfree_hnotify(hn);
}
}
/* ---------------------------------------------------------------------- */
void au_hn_ctl(struct au_hinode *hinode, int do_set)
{
if (hinode->hi_notify)
au_hnotify_op.ctl(hinode, do_set);
}
void au_hn_reset(struct inode *inode, unsigned int flags)
{
aufs_bindex_t bindex, bbot;
struct inode *hi;
struct dentry *iwhdentry;
bbot = au_ibbot(inode);
for (bindex = au_ibtop(inode); bindex <= bbot; bindex++) {
hi = au_h_iptr(inode, bindex);
if (!hi)
continue;
/* inode_lock_nested(hi, AuLsc_I_CHILD); */
iwhdentry = au_hi_wh(inode, bindex);
if (iwhdentry)
dget(iwhdentry);
au_igrab(hi);
au_set_h_iptr(inode, bindex, NULL, 0);
au_set_h_iptr(inode, bindex, au_igrab(hi),
flags & ~AuHi_XINO);
iput(hi);
dput(iwhdentry);
/* inode_unlock(hi); */
}
}
/* ---------------------------------------------------------------------- */
static int hn_xino(struct inode *inode, struct inode *h_inode)
{
int err;
aufs_bindex_t bindex, bbot, bfound, btop;
struct inode *h_i;
err = 0;
if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
pr_warn("branch root dir was changed\n");
goto out;
}
bfound = -1;
bbot = au_ibbot(inode);
btop = au_ibtop(inode);
#if 0 /* reserved for future use */
if (bindex == bbot) {
/* keep this ino in rename case */
goto out;
}
#endif
for (bindex = btop; bindex <= bbot; bindex++)
if (au_h_iptr(inode, bindex) == h_inode) {
bfound = bindex;
break;
}
if (bfound < 0)
goto out;
for (bindex = btop; bindex <= bbot; bindex++) {
h_i = au_h_iptr(inode, bindex);
if (!h_i)
continue;
err = au_xino_write(inode->i_sb, bindex, h_i->i_ino, /*ino*/0);
/* ignore this error */
/* bad action? */
}
/* children inode number will be broken */
out:
AuTraceErr(err);
return err;
}
static int hn_gen_tree(struct dentry *dentry)
{
int err, i, j, ndentry;
struct au_dcsub_pages dpages;
struct au_dpage *dpage;
struct dentry **dentries;
err = au_dpages_init(&dpages, GFP_NOFS);
if (unlikely(err))
goto out;
err = au_dcsub_pages(&dpages, dentry, NULL, NULL);
if (unlikely(err))
goto out_dpages;
for (i = 0; i < dpages.ndpage; i++) {
dpage = dpages.dpages + i;
dentries = dpage->dentries;
ndentry = dpage->ndentry;
for (j = 0; j < ndentry; j++) {
struct dentry *d;
d = dentries[j];
if (IS_ROOT(d))
continue;
au_digen_dec(d);
if (d_really_is_positive(d))
/* todo: reset children xino?
cached children only? */
au_iigen_dec(d_inode(d));
}
}
out_dpages:
au_dpages_free(&dpages);
#if 0
/* discard children */
dentry_unhash(dentry);
dput(dentry);
#endif
out:
return err;
}
/*
* return 0 if processed.
*/
static int hn_gen_by_inode(char *name, unsigned int nlen, struct inode *inode,
const unsigned int isdir)
{
int err;
struct dentry *d;
struct qstr *dname;
err = 1;
if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
pr_warn("branch root dir was changed\n");
err = 0;
goto out;
}
if (!isdir) {
AuDebugOn(!name);
au_iigen_dec(inode);
spin_lock(&inode->i_lock);
hlist_for_each_entry(d, &inode->i_dentry, d_u.d_alias) {
spin_lock(&d->d_lock);
dname = &d->d_name;
if (dname->len != nlen
&& memcmp(dname->name, name, nlen)) {
spin_unlock(&d->d_lock);
continue;
}
err = 0;
au_digen_dec(d);
spin_unlock(&d->d_lock);
break;
}
spin_unlock(&inode->i_lock);
} else {
au_fset_si(au_sbi(inode->i_sb), FAILED_REFRESH_DIR);
d = d_find_any_alias(inode);
if (!d) {
au_iigen_dec(inode);
goto out;
}
spin_lock(&d->d_lock);
dname = &d->d_name;
if (dname->len == nlen && !memcmp(dname->name, name, nlen)) {
spin_unlock(&d->d_lock);
err = hn_gen_tree(d);
spin_lock(&d->d_lock);
}
spin_unlock(&d->d_lock);
dput(d);
}
out:
AuTraceErr(err);
return err;
}
static int hn_gen_by_name(struct dentry *dentry, const unsigned int isdir)
{
int err;
if (IS_ROOT(dentry)) {
pr_warn("branch root dir was changed\n");
return 0;
}
err = 0;
if (!isdir) {
au_digen_dec(dentry);
if (d_really_is_positive(dentry))
au_iigen_dec(d_inode(dentry));
} else {
au_fset_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIR);
if (d_really_is_positive(dentry))
err = hn_gen_tree(dentry);
}
AuTraceErr(err);
return err;
}
/* ---------------------------------------------------------------------- */
/* hnotify job flags */
#define AuHnJob_XINO0 1
#define AuHnJob_GEN (1 << 1)
#define AuHnJob_DIRENT (1 << 2)
#define AuHnJob_ISDIR (1 << 3)
#define AuHnJob_TRYXINO0 (1 << 4)
#define AuHnJob_MNTPNT (1 << 5)
#define au_ftest_hnjob(flags, name) ((flags) & AuHnJob_##name)
#define au_fset_hnjob(flags, name) \
do { (flags) |= AuHnJob_##name; } while (0)
#define au_fclr_hnjob(flags, name) \
do { (flags) &= ~AuHnJob_##name; } while (0)
enum {
AuHn_CHILD,
AuHn_PARENT,
AuHnLast
};
struct au_hnotify_args {
struct inode *h_dir, *dir, *h_child_inode;
u32 mask;
unsigned int flags[AuHnLast];
unsigned int h_child_nlen;
char h_child_name[];
};
struct hn_job_args {
unsigned int flags;
struct inode *inode, *h_inode, *dir, *h_dir;
struct dentry *dentry;
char *h_name;
int h_nlen;
};
static int hn_job(struct hn_job_args *a)
{
const unsigned int isdir = au_ftest_hnjob(a->flags, ISDIR);
int e;
/* reset xino */
if (au_ftest_hnjob(a->flags, XINO0) && a->inode)
hn_xino(a->inode, a->h_inode); /* ignore this error */
if (au_ftest_hnjob(a->flags, TRYXINO0)
&& a->inode
&& a->h_inode) {
inode_lock_nested(a->h_inode, AuLsc_I_CHILD);
if (!a->h_inode->i_nlink
&& !(a->h_inode->i_state & I_LINKABLE))
hn_xino(a->inode, a->h_inode); /* ignore this error */
inode_unlock(a->h_inode);
}
/* make the generation obsolete */
if (au_ftest_hnjob(a->flags, GEN)) {
e = -1;
if (a->inode)
e = hn_gen_by_inode(a->h_name, a->h_nlen, a->inode,
isdir);
if (e && a->dentry)
hn_gen_by_name(a->dentry, isdir);
/* ignore this error */
}
/* make dir entries obsolete */
if (au_ftest_hnjob(a->flags, DIRENT) && a->inode) {
struct au_vdir *vdir;
vdir = au_ivdir(a->inode);
if (vdir)
vdir->vd_jiffy = 0;
/* IMustLock(a->inode); */
/* a->inode->i_version++; */
}
/* can do nothing but warn */
if (au_ftest_hnjob(a->flags, MNTPNT)
&& a->dentry
&& d_mountpoint(a->dentry))
pr_warn("mount-point %pd is removed or renamed\n", a->dentry);
return 0;
}
/* ---------------------------------------------------------------------- */
static struct dentry *lookup_wlock_by_name(char *name, unsigned int nlen,
struct inode *dir)
{
struct dentry *dentry, *d, *parent;
struct qstr *dname;
parent = d_find_any_alias(dir);
if (!parent)
return NULL;
dentry = NULL;
spin_lock(&parent->d_lock);
list_for_each_entry(d, &parent->d_subdirs, d_child) {
/* AuDbg("%pd\n", d); */
spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
dname = &d->d_name;
if (dname->len != nlen || memcmp(dname->name, name, nlen))
goto cont_unlock;
if (au_di(d))
au_digen_dec(d);
else
goto cont_unlock;
if (au_dcount(d) > 0) {
dentry = dget_dlock(d);
spin_unlock(&d->d_lock);
break;
}
cont_unlock:
spin_unlock(&d->d_lock);
}
spin_unlock(&parent->d_lock);
dput(parent);
if (dentry)
di_write_lock_child(dentry);
return dentry;
}
static struct inode *lookup_wlock_by_ino(struct super_block *sb,
aufs_bindex_t bindex, ino_t h_ino)
{
struct inode *inode;
ino_t ino;
int err;
inode = NULL;
err = au_xino_read(sb, bindex, h_ino, &ino);
if (!err && ino)
inode = ilookup(sb, ino);
if (!inode)
goto out;
if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
pr_warn("wrong root branch\n");
iput(inode);
inode = NULL;
goto out;
}
ii_write_lock_child(inode);
out:
return inode;
}
static void au_hn_bh(void *_args)
{
struct au_hnotify_args *a = _args;
struct super_block *sb;
aufs_bindex_t bindex, bbot, bfound;
unsigned char xino, try_iput;
int err;
struct inode *inode;
ino_t h_ino;
struct hn_job_args args;
struct dentry *dentry;
struct au_sbinfo *sbinfo;
AuDebugOn(!_args);
AuDebugOn(!a->h_dir);
AuDebugOn(!a->dir);
AuDebugOn(!a->mask);
AuDbg("mask 0x%x, i%lu, hi%lu, hci%lu\n",
a->mask, a->dir->i_ino, a->h_dir->i_ino,
a->h_child_inode ? a->h_child_inode->i_ino : 0);
inode = NULL;
dentry = NULL;
/*
* do not lock a->dir->i_mutex here
* because of d_revalidate() may cause a deadlock.
*/
sb = a->dir->i_sb;
AuDebugOn(!sb);
sbinfo = au_sbi(sb);
AuDebugOn(!sbinfo);
si_write_lock(sb, AuLock_NOPLMW);
ii_read_lock_parent(a->dir);
bfound = -1;
bbot = au_ibbot(a->dir);
for (bindex = au_ibtop(a->dir); bindex <= bbot; bindex++)
if (au_h_iptr(a->dir, bindex) == a->h_dir) {
bfound = bindex;
break;
}
ii_read_unlock(a->dir);
if (unlikely(bfound < 0))
goto out;
xino = !!au_opt_test(au_mntflags(sb), XINO);
h_ino = 0;
if (a->h_child_inode)
h_ino = a->h_child_inode->i_ino;
if (a->h_child_nlen
&& (au_ftest_hnjob(a->flags[AuHn_CHILD], GEN)
|| au_ftest_hnjob(a->flags[AuHn_CHILD], MNTPNT)))
dentry = lookup_wlock_by_name(a->h_child_name, a->h_child_nlen,
a->dir);
try_iput = 0;
if (dentry && d_really_is_positive(dentry))
inode = d_inode(dentry);
if (xino && !inode && h_ino
&& (au_ftest_hnjob(a->flags[AuHn_CHILD], XINO0)
|| au_ftest_hnjob(a->flags[AuHn_CHILD], TRYXINO0)
|| au_ftest_hnjob(a->flags[AuHn_CHILD], GEN))) {
inode = lookup_wlock_by_ino(sb, bfound, h_ino);
try_iput = 1;
}
args.flags = a->flags[AuHn_CHILD];
args.dentry = dentry;
args.inode = inode;
args.h_inode = a->h_child_inode;
args.dir = a->dir;
args.h_dir = a->h_dir;
args.h_name = a->h_child_name;
args.h_nlen = a->h_child_nlen;
err = hn_job(&args);
if (dentry) {
if (au_di(dentry))
di_write_unlock(dentry);
dput(dentry);
}
if (inode && try_iput) {
ii_write_unlock(inode);
iput(inode);
}
ii_write_lock_parent(a->dir);
args.flags = a->flags[AuHn_PARENT];
args.dentry = NULL;
args.inode = a->dir;
args.h_inode = a->h_dir;
args.dir = NULL;
args.h_dir = NULL;
args.h_name = NULL;
args.h_nlen = 0;
err = hn_job(&args);
ii_write_unlock(a->dir);
out:
iput(a->h_child_inode);
iput(a->h_dir);
iput(a->dir);
si_write_unlock(sb);
au_nwt_done(&sbinfo->si_nowait);
au_delayed_kfree(a);
}
/* ---------------------------------------------------------------------- */
int au_hnotify(struct inode *h_dir, struct au_hnotify *hnotify, u32 mask,
struct qstr *h_child_qstr, struct inode *h_child_inode)
{
int err, len;
unsigned int flags[AuHnLast], f;
unsigned char isdir, isroot, wh;
struct inode *dir;
struct au_hnotify_args *args;
char *p, *h_child_name;
err = 0;
AuDebugOn(!hnotify || !hnotify->hn_aufs_inode);
dir = igrab(hnotify->hn_aufs_inode);
if (!dir)
goto out;
isroot = (dir->i_ino == AUFS_ROOT_INO);
wh = 0;
h_child_name = (void *)h_child_qstr->name;
len = h_child_qstr->len;
if (h_child_name) {
if (len > AUFS_WH_PFX_LEN
&& !memcmp(h_child_name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
h_child_name += AUFS_WH_PFX_LEN;
len -= AUFS_WH_PFX_LEN;
wh = 1;
}
}
isdir = 0;
if (h_child_inode)
isdir = !!S_ISDIR(h_child_inode->i_mode);
flags[AuHn_PARENT] = AuHnJob_ISDIR;
flags[AuHn_CHILD] = 0;
if (isdir)
flags[AuHn_CHILD] = AuHnJob_ISDIR;
au_fset_hnjob(flags[AuHn_PARENT], DIRENT);
au_fset_hnjob(flags[AuHn_CHILD], GEN);
switch (mask & FS_EVENTS_POSS_ON_CHILD) {
case FS_MOVED_FROM:
case FS_MOVED_TO:
au_fset_hnjob(flags[AuHn_CHILD], XINO0);
au_fset_hnjob(flags[AuHn_CHILD], MNTPNT);
/*FALLTHROUGH*/
case FS_CREATE:
AuDebugOn(!h_child_name);
break;
case FS_DELETE:
/*
* aufs never be able to get this child inode.
* revalidation should be in d_revalidate()
* by checking i_nlink, i_generation or d_unhashed().
*/
AuDebugOn(!h_child_name);
au_fset_hnjob(flags[AuHn_CHILD], TRYXINO0);
au_fset_hnjob(flags[AuHn_CHILD], MNTPNT);
break;
default:
AuDebugOn(1);
}
if (wh)
h_child_inode = NULL;
err = -ENOMEM;
/* iput() and kfree() will be called in au_hnotify() */
args = kmalloc(sizeof(*args) + len + 1, GFP_NOFS);
if (unlikely(!args)) {
AuErr1("no memory\n");
iput(dir);
goto out;
}
args->flags[AuHn_PARENT] = flags[AuHn_PARENT];
args->flags[AuHn_CHILD] = flags[AuHn_CHILD];
args->mask = mask;
args->dir = dir;
args->h_dir = igrab(h_dir);
if (h_child_inode)
h_child_inode = igrab(h_child_inode); /* can be NULL */
args->h_child_inode = h_child_inode;
args->h_child_nlen = len;
if (len) {
p = (void *)args;
p += sizeof(*args);
memcpy(p, h_child_name, len);
p[len] = 0;
}
/* NFS fires the event for silly-renamed one from kworker */
f = 0;
if (!dir->i_nlink
|| (au_test_nfs(h_dir->i_sb) && (mask & FS_DELETE)))
f = AuWkq_NEST;
err = au_wkq_nowait(au_hn_bh, args, dir->i_sb, f);
if (unlikely(err)) {
pr_err("wkq %d\n", err);
iput(args->h_child_inode);
iput(args->h_dir);
iput(args->dir);
au_delayed_kfree(args);
}
out:
return err;
}
/* ---------------------------------------------------------------------- */
int au_hnotify_reset_br(unsigned int udba, struct au_branch *br, int perm)
{
int err;
AuDebugOn(!(udba & AuOptMask_UDBA));
err = 0;
if (au_hnotify_op.reset_br)
err = au_hnotify_op.reset_br(udba, br, perm);
return err;
}
int au_hnotify_init_br(struct au_branch *br, int perm)
{
int err;
err = 0;
if (au_hnotify_op.init_br)
err = au_hnotify_op.init_br(br, perm);
return err;
}
void au_hnotify_fin_br(struct au_branch *br)
{
if (au_hnotify_op.fin_br)
au_hnotify_op.fin_br(br);
}
static void au_hn_destroy_cache(void)
{
struct au_cache *cp;
flush_delayed_work(&au_dfree.dwork);
cp = au_dfree.cache + AuCache_HNOTIFY;
AuDebugOn(!llist_empty(&cp->llist));
kmem_cache_destroy(cp->cache);
cp->cache = NULL;
}
AU_CACHE_DFREE_FUNC(hnotify, HNOTIFY, hn_lnode);
int __init au_hnotify_init(void)
{
int err;
struct au_cache *cp;
err = -ENOMEM;
cp = au_dfree.cache + AuCache_HNOTIFY;
cp->cache = AuCache(au_hnotify);
if (cp->cache) {
err = 0;
if (au_hnotify_op.init)
err = au_hnotify_op.init();
if (unlikely(err))
au_hn_destroy_cache();
}
AuTraceErr(err);
return err;
}
void au_hnotify_fin(void)
{
struct au_cache *cp;
if (au_hnotify_op.fin)
au_hnotify_op.fin();
/* cf. au_cache_fin() */
cp = au_dfree.cache + AuCache_HNOTIFY;
if (cp->cache)
au_hn_destroy_cache();
}
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