/usr/src/aufs-4.9+20161219/fs/aufs/i_op_del.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/>.
*/
/*
* inode operations (del entry)
*/
#include "aufs.h"
/*
* decide if a new whiteout for @dentry is necessary or not.
* when it is necessary, prepare the parent dir for the upper branch whose
* branch index is @bcpup for creation. the actual creation of the whiteout will
* be done by caller.
* return value:
* 0: wh is unnecessary
* plus: wh is necessary
* minus: error
*/
int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
{
int need_wh, err;
aufs_bindex_t btop;
struct super_block *sb;
sb = dentry->d_sb;
btop = au_dbtop(dentry);
if (*bcpup < 0) {
*bcpup = btop;
if (au_test_ro(sb, btop, d_inode(dentry))) {
err = AuWbrCopyup(au_sbi(sb), dentry);
*bcpup = err;
if (unlikely(err < 0))
goto out;
}
} else
AuDebugOn(btop < *bcpup
|| au_test_ro(sb, *bcpup, d_inode(dentry)));
AuDbg("bcpup %d, btop %d\n", *bcpup, btop);
if (*bcpup != btop) {
err = au_cpup_dirs(dentry, *bcpup);
if (unlikely(err))
goto out;
need_wh = 1;
} else {
struct au_dinfo *dinfo, *tmp;
need_wh = -ENOMEM;
dinfo = au_di(dentry);
tmp = au_di_alloc(sb, AuLsc_DI_TMP);
if (tmp) {
au_di_cp(tmp, dinfo);
au_di_swap(tmp, dinfo);
/* returns the number of positive dentries */
need_wh = au_lkup_dentry(dentry, btop + 1,
/* AuLkup_IGNORE_PERM */ 0);
au_di_swap(tmp, dinfo);
au_rw_write_unlock(&tmp->di_rwsem);
au_di_free(tmp);
}
}
AuDbg("need_wh %d\n", need_wh);
err = need_wh;
out:
return err;
}
/*
* simple tests for the del-entry operations.
* following the checks in vfs, plus the parent-child relationship.
*/
int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
struct dentry *h_parent, int isdir)
{
int err;
umode_t h_mode;
struct dentry *h_dentry, *h_latest;
struct inode *h_inode;
h_dentry = au_h_dptr(dentry, bindex);
if (d_really_is_positive(dentry)) {
err = -ENOENT;
if (unlikely(d_is_negative(h_dentry)))
goto out;
h_inode = d_inode(h_dentry);
if (unlikely(!h_inode->i_nlink))
goto out;
h_mode = h_inode->i_mode;
if (!isdir) {
err = -EISDIR;
if (unlikely(S_ISDIR(h_mode)))
goto out;
} else if (unlikely(!S_ISDIR(h_mode))) {
err = -ENOTDIR;
goto out;
}
} else {
/* rename(2) case */
err = -EIO;
if (unlikely(d_is_positive(h_dentry)))
goto out;
}
err = -ENOENT;
/* expected parent dir is locked */
if (unlikely(h_parent != h_dentry->d_parent))
goto out;
err = 0;
/*
* rmdir a dir may break the consistency on some filesystem.
* let's try heavy test.
*/
err = -EACCES;
if (unlikely(!au_opt_test(au_mntflags(dentry->d_sb), DIRPERM1)
&& au_test_h_perm(d_inode(h_parent),
MAY_EXEC | MAY_WRITE)))
goto out;
h_latest = au_sio_lkup_one(&dentry->d_name, h_parent);
err = -EIO;
if (IS_ERR(h_latest))
goto out;
if (h_latest == h_dentry)
err = 0;
dput(h_latest);
out:
return err;
}
/*
* decide the branch where we operate for @dentry. the branch index will be set
* @rbcpup. after diciding it, 'pin' it and store the timestamps of the parent
* dir for reverting.
* when a new whiteout is necessary, create it.
*/
static struct dentry*
lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
struct au_dtime *dt, struct au_pin *pin)
{
struct dentry *wh_dentry;
struct super_block *sb;
struct path h_path;
int err, need_wh;
unsigned int udba;
aufs_bindex_t bcpup;
need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
wh_dentry = ERR_PTR(need_wh);
if (unlikely(need_wh < 0))
goto out;
sb = dentry->d_sb;
udba = au_opt_udba(sb);
bcpup = *rbcpup;
err = au_pin(pin, dentry, bcpup, udba,
AuPin_DI_LOCKED | AuPin_MNT_WRITE);
wh_dentry = ERR_PTR(err);
if (unlikely(err))
goto out;
h_path.dentry = au_pinned_h_parent(pin);
if (udba != AuOpt_UDBA_NONE
&& au_dbtop(dentry) == bcpup) {
err = au_may_del(dentry, bcpup, h_path.dentry, isdir);
wh_dentry = ERR_PTR(err);
if (unlikely(err))
goto out_unpin;
}
h_path.mnt = au_sbr_mnt(sb, bcpup);
au_dtime_store(dt, au_pinned_parent(pin), &h_path);
wh_dentry = NULL;
if (!need_wh)
goto out; /* success, no need to create whiteout */
wh_dentry = au_wh_create(dentry, bcpup, h_path.dentry);
if (IS_ERR(wh_dentry))
goto out_unpin;
/* returns with the parent is locked and wh_dentry is dget-ed */
goto out; /* success */
out_unpin:
au_unpin(pin);
out:
return wh_dentry;
}
/*
* when removing a dir, rename it to a unique temporary whiteout-ed name first
* in order to be revertible and save time for removing many child whiteouts
* under the dir.
* returns 1 when there are too many child whiteout and caller should remove
* them asynchronously. returns 0 when the number of children is enough small to
* remove now or the branch fs is a remote fs.
* otherwise return an error.
*/
static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
struct au_nhash *whlist, struct inode *dir)
{
int rmdir_later, err, dirwh;
struct dentry *h_dentry;
struct super_block *sb;
struct inode *inode;
sb = dentry->d_sb;
SiMustAnyLock(sb);
h_dentry = au_h_dptr(dentry, bindex);
err = au_whtmp_ren(h_dentry, au_sbr(sb, bindex));
if (unlikely(err))
goto out;
/* stop monitoring */
inode = d_inode(dentry);
au_hn_free(au_hi(inode, bindex));
if (!au_test_fs_remote(h_dentry->d_sb)) {
dirwh = au_sbi(sb)->si_dirwh;
rmdir_later = (dirwh <= 1);
if (!rmdir_later)
rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
dirwh);
if (rmdir_later)
return rmdir_later;
}
err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
if (unlikely(err)) {
AuIOErr("rmdir %pd, b%d failed, %d. ignored\n",
h_dentry, bindex, err);
err = 0;
}
out:
AuTraceErr(err);
return err;
}
/*
* final procedure for deleting a entry.
* maintain dentry and iattr.
*/
static void epilog(struct inode *dir, struct dentry *dentry,
aufs_bindex_t bindex)
{
struct inode *inode;
inode = d_inode(dentry);
d_drop(dentry);
inode->i_ctime = dir->i_ctime;
au_dir_ts(dir, bindex);
dir->i_version++;
}
/*
* when an error happened, remove the created whiteout and revert everything.
*/
static int do_revert(int err, struct inode *dir, aufs_bindex_t bindex,
aufs_bindex_t bwh, struct dentry *wh_dentry,
struct dentry *dentry, struct au_dtime *dt)
{
int rerr;
struct path h_path = {
.dentry = wh_dentry,
.mnt = au_sbr_mnt(dir->i_sb, bindex)
};
rerr = au_wh_unlink_dentry(au_h_iptr(dir, bindex), &h_path, dentry);
if (!rerr) {
au_set_dbwh(dentry, bwh);
au_dtime_revert(dt);
return 0;
}
AuIOErr("%pd reverting whiteout failed(%d, %d)\n", dentry, err, rerr);
return -EIO;
}
/* ---------------------------------------------------------------------- */
int aufs_unlink(struct inode *dir, struct dentry *dentry)
{
int err;
aufs_bindex_t bwh, bindex, btop;
struct inode *inode, *h_dir, *delegated;
struct dentry *parent, *wh_dentry;
/* to reuduce stack size */
struct {
struct au_dtime dt;
struct au_pin pin;
struct path h_path;
} *a;
IMustLock(dir);
err = -ENOMEM;
a = kmalloc(sizeof(*a), GFP_NOFS);
if (unlikely(!a))
goto out;
err = aufs_read_lock(dentry, AuLock_DW | AuLock_GEN);
if (unlikely(err))
goto out_free;
err = au_d_hashed_positive(dentry);
if (unlikely(err))
goto out_unlock;
inode = d_inode(dentry);
IMustLock(inode);
err = -EISDIR;
if (unlikely(d_is_dir(dentry)))
goto out_unlock; /* possible? */
btop = au_dbtop(dentry);
bwh = au_dbwh(dentry);
bindex = -1;
parent = dentry->d_parent; /* dir inode is locked */
di_write_lock_parent(parent);
wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &a->dt,
&a->pin);
err = PTR_ERR(wh_dentry);
if (IS_ERR(wh_dentry))
goto out_parent;
a->h_path.mnt = au_sbr_mnt(dentry->d_sb, btop);
a->h_path.dentry = au_h_dptr(dentry, btop);
dget(a->h_path.dentry);
if (bindex == btop) {
h_dir = au_pinned_h_dir(&a->pin);
delegated = NULL;
err = vfsub_unlink(h_dir, &a->h_path, &delegated, /*force*/0);
if (unlikely(err == -EWOULDBLOCK)) {
pr_warn("cannot retry for NFSv4 delegation"
" for an internal unlink\n");
iput(delegated);
}
} else {
/* dir inode is locked */
h_dir = d_inode(wh_dentry->d_parent);
IMustLock(h_dir);
err = 0;
}
if (!err) {
vfsub_drop_nlink(inode);
epilog(dir, dentry, bindex);
/* update target timestamps */
if (bindex == btop) {
vfsub_update_h_iattr(&a->h_path, /*did*/NULL);
/*ignore*/
inode->i_ctime = d_inode(a->h_path.dentry)->i_ctime;
} else
/* todo: this timestamp may be reverted later */
inode->i_ctime = h_dir->i_ctime;
goto out_unpin; /* success */
}
/* revert */
if (wh_dentry) {
int rerr;
rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
&a->dt);
if (rerr)
err = rerr;
}
out_unpin:
au_unpin(&a->pin);
dput(wh_dentry);
dput(a->h_path.dentry);
out_parent:
di_write_unlock(parent);
out_unlock:
aufs_read_unlock(dentry, AuLock_DW);
out_free:
au_delayed_kfree(a);
out:
return err;
}
int aufs_rmdir(struct inode *dir, struct dentry *dentry)
{
int err, rmdir_later;
aufs_bindex_t bwh, bindex, btop;
struct inode *inode;
struct dentry *parent, *wh_dentry, *h_dentry;
struct au_whtmp_rmdir *args;
/* to reuduce stack size */
struct {
struct au_dtime dt;
struct au_pin pin;
} *a;
IMustLock(dir);
err = -ENOMEM;
a = kmalloc(sizeof(*a), GFP_NOFS);
if (unlikely(!a))
goto out;
err = aufs_read_lock(dentry, AuLock_DW | AuLock_FLUSH | AuLock_GEN);
if (unlikely(err))
goto out_free;
err = au_alive_dir(dentry);
if (unlikely(err))
goto out_unlock;
inode = d_inode(dentry);
IMustLock(inode);
err = -ENOTDIR;
if (unlikely(!d_is_dir(dentry)))
goto out_unlock; /* possible? */
err = -ENOMEM;
args = au_whtmp_rmdir_alloc(dir->i_sb, GFP_NOFS);
if (unlikely(!args))
goto out_unlock;
parent = dentry->d_parent; /* dir inode is locked */
di_write_lock_parent(parent);
err = au_test_empty(dentry, &args->whlist);
if (unlikely(err))
goto out_parent;
btop = au_dbtop(dentry);
bwh = au_dbwh(dentry);
bindex = -1;
wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &a->dt,
&a->pin);
err = PTR_ERR(wh_dentry);
if (IS_ERR(wh_dentry))
goto out_parent;
h_dentry = au_h_dptr(dentry, btop);
dget(h_dentry);
rmdir_later = 0;
if (bindex == btop) {
err = renwh_and_rmdir(dentry, btop, &args->whlist, dir);
if (err > 0) {
rmdir_later = err;
err = 0;
}
} else {
/* stop monitoring */
au_hn_free(au_hi(inode, btop));
/* dir inode is locked */
IMustLock(d_inode(wh_dentry->d_parent));
err = 0;
}
if (!err) {
vfsub_dead_dir(inode);
au_set_dbdiropq(dentry, -1);
epilog(dir, dentry, bindex);
if (rmdir_later) {
au_whtmp_kick_rmdir(dir, btop, h_dentry, args);
args = NULL;
}
goto out_unpin; /* success */
}
/* revert */
AuLabel(revert);
if (wh_dentry) {
int rerr;
rerr = do_revert(err, dir, bindex, bwh, wh_dentry, dentry,
&a->dt);
if (rerr)
err = rerr;
}
out_unpin:
au_unpin(&a->pin);
dput(wh_dentry);
dput(h_dentry);
out_parent:
di_write_unlock(parent);
if (args)
au_whtmp_rmdir_free(args);
out_unlock:
aufs_read_unlock(dentry, AuLock_DW);
out_free:
au_delayed_kfree(a);
out:
AuTraceErr(err);
return err;
}
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