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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2005-2019 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/>.
*/
/*
* superblock private data
*/
#include "aufs.h"
/*
* they are necessary regardless sysfs is disabled.
*/
void au_si_free(struct kobject *kobj)
{
int i;
struct au_sbinfo *sbinfo;
char *locked __maybe_unused; /* debug only */
sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
for (i = 0; i < AuPlink_NHASH; i++)
AuDebugOn(!hlist_bl_empty(sbinfo->si_plink + i));
AuDebugOn(atomic_read(&sbinfo->si_nowait.nw_len));
AuLCntZero(au_lcnt_read(&sbinfo->si_ninodes, /*do_rev*/0));
au_lcnt_fin(&sbinfo->si_ninodes, /*do_sync*/0);
AuLCntZero(au_lcnt_read(&sbinfo->si_nfiles, /*do_rev*/0));
au_lcnt_fin(&sbinfo->si_nfiles, /*do_sync*/0);
dbgaufs_si_fin(sbinfo);
au_rw_write_lock(&sbinfo->si_rwsem);
au_br_free(sbinfo);
au_rw_write_unlock(&sbinfo->si_rwsem);
au_kfree_try_rcu(sbinfo->si_branch);
mutex_destroy(&sbinfo->si_xib_mtx);
AuRwDestroy(&sbinfo->si_rwsem);
au_lcnt_wait_for_fin(&sbinfo->si_ninodes);
/* si_nfiles is waited too */
au_kfree_rcu(sbinfo);
}
int au_si_alloc(struct super_block *sb)
{
int err, i;
struct au_sbinfo *sbinfo;
err = -ENOMEM;
sbinfo = kzalloc(sizeof(*sbinfo), GFP_NOFS);
if (unlikely(!sbinfo))
goto out;
/* will be reallocated separately */
sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
if (unlikely(!sbinfo->si_branch))
goto out_sbinfo;
err = sysaufs_si_init(sbinfo);
if (!err) {
dbgaufs_si_null(sbinfo);
err = dbgaufs_si_init(sbinfo);
if (unlikely(err))
kobject_put(&sbinfo->si_kobj);
}
if (unlikely(err))
goto out_br;
au_nwt_init(&sbinfo->si_nowait);
au_rw_init_wlock(&sbinfo->si_rwsem);
au_lcnt_init(&sbinfo->si_ninodes, /*release*/NULL);
au_lcnt_init(&sbinfo->si_nfiles, /*release*/NULL);
sbinfo->si_bbot = -1;
sbinfo->si_last_br_id = AUFS_BRANCH_MAX / 2;
sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
sbinfo->si_wbr_create = AuWbrCreate_Def;
sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + sbinfo->si_wbr_copyup;
sbinfo->si_wbr_create_ops = au_wbr_create_ops + sbinfo->si_wbr_create;
au_fhsm_init(sbinfo);
sbinfo->si_mntflags = au_opts_plink(AuOpt_Def);
sbinfo->si_xino_jiffy = jiffies;
sbinfo->si_xino_expire
= msecs_to_jiffies(AUFS_XINO_DEF_SEC * MSEC_PER_SEC);
mutex_init(&sbinfo->si_xib_mtx);
/* leave si_xib_last_pindex and si_xib_next_bit */
INIT_HLIST_BL_HEAD(&sbinfo->si_aopen);
sbinfo->si_rdcache = msecs_to_jiffies(AUFS_RDCACHE_DEF * MSEC_PER_SEC);
sbinfo->si_rdblk = AUFS_RDBLK_DEF;
sbinfo->si_rdhash = AUFS_RDHASH_DEF;
sbinfo->si_dirwh = AUFS_DIRWH_DEF;
for (i = 0; i < AuPlink_NHASH; i++)
INIT_HLIST_BL_HEAD(sbinfo->si_plink + i);
init_waitqueue_head(&sbinfo->si_plink_wq);
spin_lock_init(&sbinfo->si_plink_maint_lock);
INIT_HLIST_BL_HEAD(&sbinfo->si_files);
/* with getattr by default */
sbinfo->si_iop_array = aufs_iop;
/* leave other members for sysaufs and si_mnt. */
sbinfo->si_sb = sb;
sb->s_fs_info = sbinfo;
si_pid_set(sb);
return 0; /* success */
out_br:
au_kfree_try_rcu(sbinfo->si_branch);
out_sbinfo:
au_kfree_rcu(sbinfo);
out:
return err;
}
int au_sbr_realloc(struct au_sbinfo *sbinfo, int nbr, int may_shrink)
{
int err, sz;
struct au_branch **brp;
AuRwMustWriteLock(&sbinfo->si_rwsem);
err = -ENOMEM;
sz = sizeof(*brp) * (sbinfo->si_bbot + 1);
if (unlikely(!sz))
sz = sizeof(*brp);
brp = au_kzrealloc(sbinfo->si_branch, sz, sizeof(*brp) * nbr, GFP_NOFS,
may_shrink);
if (brp) {
sbinfo->si_branch = brp;
err = 0;
}
return err;
}
/* ---------------------------------------------------------------------- */
unsigned int au_sigen_inc(struct super_block *sb)
{
unsigned int gen;
struct inode *inode;
SiMustWriteLock(sb);
gen = ++au_sbi(sb)->si_generation;
au_update_digen(sb->s_root);
inode = d_inode(sb->s_root);
au_update_iigen(inode, /*half*/0);
inode_inc_iversion(inode);
return gen;
}
aufs_bindex_t au_new_br_id(struct super_block *sb)
{
aufs_bindex_t br_id;
int i;
struct au_sbinfo *sbinfo;
SiMustWriteLock(sb);
sbinfo = au_sbi(sb);
for (i = 0; i <= AUFS_BRANCH_MAX; i++) {
br_id = ++sbinfo->si_last_br_id;
AuDebugOn(br_id < 0);
if (br_id && au_br_index(sb, br_id) < 0)
return br_id;
}
return -1;
}
/* ---------------------------------------------------------------------- */
/* it is ok that new 'nwt' tasks are appended while we are sleeping */
int si_read_lock(struct super_block *sb, int flags)
{
int err;
err = 0;
if (au_ftest_lock(flags, FLUSH))
au_nwt_flush(&au_sbi(sb)->si_nowait);
si_noflush_read_lock(sb);
err = au_plink_maint(sb, flags);
if (unlikely(err))
si_read_unlock(sb);
return err;
}
int si_write_lock(struct super_block *sb, int flags)
{
int err;
if (au_ftest_lock(flags, FLUSH))
au_nwt_flush(&au_sbi(sb)->si_nowait);
si_noflush_write_lock(sb);
err = au_plink_maint(sb, flags);
if (unlikely(err))
si_write_unlock(sb);
return err;
}
/* dentry and super_block lock. call at entry point */
int aufs_read_lock(struct dentry *dentry, int flags)
{
int err;
struct super_block *sb;
sb = dentry->d_sb;
err = si_read_lock(sb, flags);
if (unlikely(err))
goto out;
if (au_ftest_lock(flags, DW))
di_write_lock_child(dentry);
else
di_read_lock_child(dentry, flags);
if (au_ftest_lock(flags, GEN)) {
err = au_digen_test(dentry, au_sigen(sb));
if (!au_opt_test(au_mntflags(sb), UDBA_NONE))
AuDebugOn(!err && au_dbrange_test(dentry));
else if (!err)
err = au_dbrange_test(dentry);
if (unlikely(err))
aufs_read_unlock(dentry, flags);
}
out:
return err;
}
void aufs_read_unlock(struct dentry *dentry, int flags)
{
if (au_ftest_lock(flags, DW))
di_write_unlock(dentry);
else
di_read_unlock(dentry, flags);
si_read_unlock(dentry->d_sb);
}
void aufs_write_lock(struct dentry *dentry)
{
si_write_lock(dentry->d_sb, AuLock_FLUSH | AuLock_NOPLMW);
di_write_lock_child(dentry);
}
void aufs_write_unlock(struct dentry *dentry)
{
di_write_unlock(dentry);
si_write_unlock(dentry->d_sb);
}
int aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
{
int err;
unsigned int sigen;
struct super_block *sb;
sb = d1->d_sb;
err = si_read_lock(sb, flags);
if (unlikely(err))
goto out;
di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIRS));
if (au_ftest_lock(flags, GEN)) {
sigen = au_sigen(sb);
err = au_digen_test(d1, sigen);
AuDebugOn(!err && au_dbrange_test(d1));
if (!err) {
err = au_digen_test(d2, sigen);
AuDebugOn(!err && au_dbrange_test(d2));
}
if (unlikely(err))
aufs_read_and_write_unlock2(d1, d2);
}
out:
return err;
}
void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
{
di_write_unlock2(d1, d2);
si_read_unlock(d1->d_sb);
}
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