/usr/src/aufs-4.9+20161219/fs/aufs/dinfo.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/>.
*/
/*
* dentry private data
*/
#include "aufs.h"
void au_di_init_once(void *_dinfo)
{
struct au_dinfo *dinfo = _dinfo;
au_rw_init(&dinfo->di_rwsem);
}
struct au_dinfo *au_di_alloc(struct super_block *sb, unsigned int lsc)
{
struct au_dinfo *dinfo;
int nbr, i;
dinfo = au_cache_alloc_dinfo();
if (unlikely(!dinfo))
goto out;
nbr = au_sbbot(sb) + 1;
if (nbr <= 0)
nbr = 1;
dinfo->di_hdentry = kcalloc(nbr, sizeof(*dinfo->di_hdentry), GFP_NOFS);
if (dinfo->di_hdentry) {
au_rw_write_lock_nested(&dinfo->di_rwsem, lsc);
dinfo->di_btop = -1;
dinfo->di_bbot = -1;
dinfo->di_bwh = -1;
dinfo->di_bdiropq = -1;
dinfo->di_tmpfile = 0;
for (i = 0; i < nbr; i++)
dinfo->di_hdentry[i].hd_id = -1;
goto out;
}
au_cache_dfree_dinfo(dinfo);
dinfo = NULL;
out:
return dinfo;
}
void au_di_free(struct au_dinfo *dinfo)
{
struct au_hdentry *p;
aufs_bindex_t bbot, bindex;
/* dentry may not be revalidated */
bindex = dinfo->di_btop;
if (bindex >= 0) {
bbot = dinfo->di_bbot;
p = au_hdentry(dinfo, bindex);
while (bindex++ <= bbot)
au_hdput(p++);
}
au_delayed_kfree(dinfo->di_hdentry);
au_cache_dfree_dinfo(dinfo);
}
void au_di_swap(struct au_dinfo *a, struct au_dinfo *b)
{
struct au_hdentry *p;
aufs_bindex_t bi;
AuRwMustWriteLock(&a->di_rwsem);
AuRwMustWriteLock(&b->di_rwsem);
#define DiSwap(v, name) \
do { \
v = a->di_##name; \
a->di_##name = b->di_##name; \
b->di_##name = v; \
} while (0)
DiSwap(p, hdentry);
DiSwap(bi, btop);
DiSwap(bi, bbot);
DiSwap(bi, bwh);
DiSwap(bi, bdiropq);
/* smp_mb(); */
#undef DiSwap
}
void au_di_cp(struct au_dinfo *dst, struct au_dinfo *src)
{
AuRwMustWriteLock(&dst->di_rwsem);
AuRwMustWriteLock(&src->di_rwsem);
dst->di_btop = src->di_btop;
dst->di_bbot = src->di_bbot;
dst->di_bwh = src->di_bwh;
dst->di_bdiropq = src->di_bdiropq;
/* smp_mb(); */
}
int au_di_init(struct dentry *dentry)
{
int err;
struct super_block *sb;
struct au_dinfo *dinfo;
err = 0;
sb = dentry->d_sb;
dinfo = au_di_alloc(sb, AuLsc_DI_CHILD);
if (dinfo) {
atomic_set(&dinfo->di_generation, au_sigen(sb));
/* smp_mb(); */ /* atomic_set */
dentry->d_fsdata = dinfo;
} else
err = -ENOMEM;
return err;
}
void au_di_fin(struct dentry *dentry)
{
struct au_dinfo *dinfo;
dinfo = au_di(dentry);
AuRwDestroy(&dinfo->di_rwsem);
au_di_free(dinfo);
}
int au_di_realloc(struct au_dinfo *dinfo, int nbr, int may_shrink)
{
int err, sz;
struct au_hdentry *hdp;
AuRwMustWriteLock(&dinfo->di_rwsem);
err = -ENOMEM;
sz = sizeof(*hdp) * (dinfo->di_bbot + 1);
if (!sz)
sz = sizeof(*hdp);
hdp = au_kzrealloc(dinfo->di_hdentry, sz, sizeof(*hdp) * nbr, GFP_NOFS,
may_shrink);
if (hdp) {
dinfo->di_hdentry = hdp;
err = 0;
}
return err;
}
/* ---------------------------------------------------------------------- */
static void do_ii_write_lock(struct inode *inode, unsigned int lsc)
{
switch (lsc) {
case AuLsc_DI_CHILD:
ii_write_lock_child(inode);
break;
case AuLsc_DI_CHILD2:
ii_write_lock_child2(inode);
break;
case AuLsc_DI_CHILD3:
ii_write_lock_child3(inode);
break;
case AuLsc_DI_PARENT:
ii_write_lock_parent(inode);
break;
case AuLsc_DI_PARENT2:
ii_write_lock_parent2(inode);
break;
case AuLsc_DI_PARENT3:
ii_write_lock_parent3(inode);
break;
default:
BUG();
}
}
static void do_ii_read_lock(struct inode *inode, unsigned int lsc)
{
switch (lsc) {
case AuLsc_DI_CHILD:
ii_read_lock_child(inode);
break;
case AuLsc_DI_CHILD2:
ii_read_lock_child2(inode);
break;
case AuLsc_DI_CHILD3:
ii_read_lock_child3(inode);
break;
case AuLsc_DI_PARENT:
ii_read_lock_parent(inode);
break;
case AuLsc_DI_PARENT2:
ii_read_lock_parent2(inode);
break;
case AuLsc_DI_PARENT3:
ii_read_lock_parent3(inode);
break;
default:
BUG();
}
}
void di_read_lock(struct dentry *d, int flags, unsigned int lsc)
{
struct inode *inode;
au_rw_read_lock_nested(&au_di(d)->di_rwsem, lsc);
if (d_really_is_positive(d)) {
inode = d_inode(d);
if (au_ftest_lock(flags, IW))
do_ii_write_lock(inode, lsc);
else if (au_ftest_lock(flags, IR))
do_ii_read_lock(inode, lsc);
}
}
void di_read_unlock(struct dentry *d, int flags)
{
struct inode *inode;
if (d_really_is_positive(d)) {
inode = d_inode(d);
if (au_ftest_lock(flags, IW)) {
au_dbg_verify_dinode(d);
ii_write_unlock(inode);
} else if (au_ftest_lock(flags, IR)) {
au_dbg_verify_dinode(d);
ii_read_unlock(inode);
}
}
au_rw_read_unlock(&au_di(d)->di_rwsem);
}
void di_downgrade_lock(struct dentry *d, int flags)
{
if (d_really_is_positive(d) && au_ftest_lock(flags, IR))
ii_downgrade_lock(d_inode(d));
au_rw_dgrade_lock(&au_di(d)->di_rwsem);
}
void di_write_lock(struct dentry *d, unsigned int lsc)
{
au_rw_write_lock_nested(&au_di(d)->di_rwsem, lsc);
if (d_really_is_positive(d))
do_ii_write_lock(d_inode(d), lsc);
}
void di_write_unlock(struct dentry *d)
{
au_dbg_verify_dinode(d);
if (d_really_is_positive(d))
ii_write_unlock(d_inode(d));
au_rw_write_unlock(&au_di(d)->di_rwsem);
}
void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
{
AuDebugOn(d1 == d2
|| d_inode(d1) == d_inode(d2)
|| d1->d_sb != d2->d_sb);
if (isdir && au_test_subdir(d1, d2)) {
di_write_lock_child(d1);
di_write_lock_child2(d2);
} else {
/* there should be no races */
di_write_lock_child(d2);
di_write_lock_child2(d1);
}
}
void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
{
AuDebugOn(d1 == d2
|| d_inode(d1) == d_inode(d2)
|| d1->d_sb != d2->d_sb);
if (isdir && au_test_subdir(d1, d2)) {
di_write_lock_parent(d1);
di_write_lock_parent2(d2);
} else {
/* there should be no races */
di_write_lock_parent(d2);
di_write_lock_parent2(d1);
}
}
void di_write_unlock2(struct dentry *d1, struct dentry *d2)
{
di_write_unlock(d1);
if (d_inode(d1) == d_inode(d2))
au_rw_write_unlock(&au_di(d2)->di_rwsem);
else
di_write_unlock(d2);
}
/* ---------------------------------------------------------------------- */
struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)
{
struct dentry *d;
DiMustAnyLock(dentry);
if (au_dbtop(dentry) < 0 || bindex < au_dbtop(dentry))
return NULL;
AuDebugOn(bindex < 0);
d = au_hdentry(au_di(dentry), bindex)->hd_dentry;
AuDebugOn(d && au_dcount(d) <= 0);
return d;
}
/*
* extended version of au_h_dptr().
* returns a hashed and positive (or linkable) h_dentry in bindex, NULL, or
* error.
*/
struct dentry *au_h_d_alias(struct dentry *dentry, aufs_bindex_t bindex)
{
struct dentry *h_dentry;
struct inode *inode, *h_inode;
AuDebugOn(d_really_is_negative(dentry));
h_dentry = NULL;
if (au_dbtop(dentry) <= bindex
&& bindex <= au_dbbot(dentry))
h_dentry = au_h_dptr(dentry, bindex);
if (h_dentry && !au_d_linkable(h_dentry)) {
dget(h_dentry);
goto out; /* success */
}
inode = d_inode(dentry);
AuDebugOn(bindex < au_ibtop(inode));
AuDebugOn(au_ibbot(inode) < bindex);
h_inode = au_h_iptr(inode, bindex);
h_dentry = d_find_alias(h_inode);
if (h_dentry) {
if (!IS_ERR(h_dentry)) {
if (!au_d_linkable(h_dentry))
goto out; /* success */
dput(h_dentry);
} else
goto out;
}
if (au_opt_test(au_mntflags(dentry->d_sb), PLINK)) {
h_dentry = au_plink_lkup(inode, bindex);
AuDebugOn(!h_dentry);
if (!IS_ERR(h_dentry)) {
if (!au_d_hashed_positive(h_dentry))
goto out; /* success */
dput(h_dentry);
h_dentry = NULL;
}
}
out:
AuDbgDentry(h_dentry);
return h_dentry;
}
aufs_bindex_t au_dbtail(struct dentry *dentry)
{
aufs_bindex_t bbot, bwh;
bbot = au_dbbot(dentry);
if (0 <= bbot) {
bwh = au_dbwh(dentry);
if (!bwh)
return bwh;
if (0 < bwh && bwh < bbot)
return bwh - 1;
}
return bbot;
}
aufs_bindex_t au_dbtaildir(struct dentry *dentry)
{
aufs_bindex_t bbot, bopq;
bbot = au_dbtail(dentry);
if (0 <= bbot) {
bopq = au_dbdiropq(dentry);
if (0 <= bopq && bopq < bbot)
bbot = bopq;
}
return bbot;
}
/* ---------------------------------------------------------------------- */
void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
struct dentry *h_dentry)
{
struct au_dinfo *dinfo;
struct au_hdentry *hd;
struct au_branch *br;
DiMustWriteLock(dentry);
dinfo = au_di(dentry);
hd = au_hdentry(dinfo, bindex);
au_hdput(hd);
hd->hd_dentry = h_dentry;
if (h_dentry) {
br = au_sbr(dentry->d_sb, bindex);
hd->hd_id = br->br_id;
}
}
int au_dbrange_test(struct dentry *dentry)
{
int err;
aufs_bindex_t btop, bbot;
err = 0;
btop = au_dbtop(dentry);
bbot = au_dbbot(dentry);
if (btop >= 0)
AuDebugOn(bbot < 0 && btop > bbot);
else {
err = -EIO;
AuDebugOn(bbot >= 0);
}
return err;
}
int au_digen_test(struct dentry *dentry, unsigned int sigen)
{
int err;
err = 0;
if (unlikely(au_digen(dentry) != sigen
|| au_iigen_test(d_inode(dentry), sigen)))
err = -EIO;
return err;
}
void au_update_digen(struct dentry *dentry)
{
atomic_set(&au_di(dentry)->di_generation, au_sigen(dentry->d_sb));
/* smp_mb(); */ /* atomic_set */
}
void au_update_dbrange(struct dentry *dentry, int do_put_zero)
{
struct au_dinfo *dinfo;
struct dentry *h_d;
struct au_hdentry *hdp;
aufs_bindex_t bindex, bbot;
DiMustWriteLock(dentry);
dinfo = au_di(dentry);
if (!dinfo || dinfo->di_btop < 0)
return;
if (do_put_zero) {
bbot = dinfo->di_bbot;
bindex = dinfo->di_btop;
hdp = au_hdentry(dinfo, bindex);
for (; bindex <= bbot; bindex++, hdp++) {
h_d = hdp->hd_dentry;
if (h_d && d_is_negative(h_d))
au_set_h_dptr(dentry, bindex, NULL);
}
}
dinfo->di_btop = 0;
hdp = au_hdentry(dinfo, dinfo->di_btop);
for (; dinfo->di_btop <= dinfo->di_bbot; dinfo->di_btop++, hdp++)
if (hdp->hd_dentry)
break;
if (dinfo->di_btop > dinfo->di_bbot) {
dinfo->di_btop = -1;
dinfo->di_bbot = -1;
return;
}
hdp = au_hdentry(dinfo, dinfo->di_bbot);
for (; dinfo->di_bbot >= 0; dinfo->di_bbot--, hdp--)
if (hdp->hd_dentry)
break;
AuDebugOn(dinfo->di_btop > dinfo->di_bbot || dinfo->di_bbot < 0);
}
void au_update_dbtop(struct dentry *dentry)
{
aufs_bindex_t bindex, bbot;
struct dentry *h_dentry;
bbot = au_dbbot(dentry);
for (bindex = au_dbtop(dentry); bindex <= bbot; bindex++) {
h_dentry = au_h_dptr(dentry, bindex);
if (!h_dentry)
continue;
if (d_is_positive(h_dentry)) {
au_set_dbtop(dentry, bindex);
return;
}
au_set_h_dptr(dentry, bindex, NULL);
}
}
void au_update_dbbot(struct dentry *dentry)
{
aufs_bindex_t bindex, btop;
struct dentry *h_dentry;
btop = au_dbtop(dentry);
for (bindex = au_dbbot(dentry); bindex >= btop; bindex--) {
h_dentry = au_h_dptr(dentry, bindex);
if (!h_dentry)
continue;
if (d_is_positive(h_dentry)) {
au_set_dbbot(dentry, bindex);
return;
}
au_set_h_dptr(dentry, bindex, NULL);
}
}
int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry)
{
aufs_bindex_t bindex, bbot;
bbot = au_dbbot(dentry);
for (bindex = au_dbtop(dentry); bindex <= bbot; bindex++)
if (au_h_dptr(dentry, bindex) == h_dentry)
return bindex;
return -1;
}
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