/*
* 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 bstart;
struct super_block *sb;
sb = dentry->d_sb;
bstart = au_dbstart(dentry);
if (*bcpup < 0) {
*bcpup = bstart;
if (au_test_ro(sb, bstart, dentry->d_inode)) {
err = AuWbrCopyup(au_sbi(sb), dentry);
*bcpup = err;
if (unlikely(err < 0))
goto out;
}
} else
AuDebugOn(bstart < *bcpup
|| au_test_ro(sb, *bcpup, dentry->d_inode));
AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);
if (*bcpup != bstart) {
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, bstart + 1, /*type*/0,
/*nd*/NULL);
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;
}
static int au_mvd_args_intermediate(const unsigned char dmsg,
struct au_mvd_args *a)
{
int err;
struct au_dinfo *dinfo, *tmp;
/* lookup the next lower positive entry */
err = -ENOMEM;
tmp = au_di_alloc(a->sb, AuLsc_DI_TMP);
if (unlikely(!tmp))
goto out;
a->bfound = -1;
a->bwh = -1;
dinfo = au_di(a->dentry);
au_di_cp(tmp, dinfo);
au_di_swap(tmp, dinfo);
/* returns the number of positive dentries */
err = au_lkup_dentry(a->dentry, a->mvd_bsrc + 1, /*type*/0);
if (!err)
a->bwh = au_dbwh(a->dentry);
else if (err > 0)
a->bfound = au_dbstart(a->dentry);
au_di_swap(tmp, dinfo);
au_rw_write_unlock(&tmp->di_rwsem);
au_di_free(tmp);
if (unlikely(err < 0))
AU_MVD_PR(dmsg, "failed look-up lower\n");
/*
* here, we have these cases.
* bfound == -1
* no positive dentry under bsrc. there are more sub-cases.
* bwh < 0
* there no whiteout, we can safely move-down.
* bwh <= bsrc
* impossible
* bsrc < bwh && bwh < bdst
* there is a whiteout on RO branch. cannot proceed.
* bwh == bdst
* there is a whiteout on the RW target branch. it should
* be removed.
* bdst < bwh
* there is a whiteout somewhere unrelated branch.
* -1 < bfound && bfound <= bsrc
* impossible.
* bfound < bdst
* found, but it is on RO branch between bsrc and bdst. cannot
* proceed.
* bfound == bdst
* found, replace it if AUFS_MVDOWN_FORCE is set. otherwise return
* error.
* bdst < bfound
* found, after we create the file on bdst, it will be hidden.
*/
AuDebugOn(a->bfound == -1
&& a->bwh != -1
&& a->bwh <= a->mvd_bsrc);
AuDebugOn(-1 < a->bfound
&& a->bfound <= a->mvd_bsrc);
err = -EINVAL;
if (a->bfound == -1
&& a->mvd_bsrc < a->bwh
&& a->bwh != -1
&& a->bwh < a->mvd_bdst) {
a->mvd_errno = EAU_MVDOWN_WHITEOUT;
AU_MVD_PR(dmsg, "bsrc %d, bdst %d, bfound %d, bwh %d\n",
a->mvd_bsrc, a->mvd_bdst, a->bfound, a->bwh);
goto out;
} else if (a->bfound != -1 && a->bfound < a->mvd_bdst) {
a->mvd_errno = EAU_MVDOWN_UPPER;
AU_MVD_PR(dmsg, "bdst %d, bfound %d\n",
a->mvd_bdst, a->bfound);
goto out;
}
err = 0; /* success */
out:
AuTraceErr(err);
return err;
}
/*
* By adding a dirty branch, a cached dentry may be affected in various ways.
*
* a dirty branch is added
* - on the top of layers
* - in the middle of layers
* - to the bottom of layers
*
* on the added branch there exists
* - a whiteout
* - a diropq
* - a same named entry
* + exist
* * negative --> positive
* * positive --> positive
* - type is unchanged
* - type is changed
* + doesn't exist
* * negative --> negative
* * positive --> negative (rejected by au_br_del() for non-dir case)
* - none
*/
static int au_refresh_by_dinfo(struct dentry *dentry, struct au_dinfo *dinfo,
struct au_dinfo *tmp)
{
int err;
aufs_bindex_t bindex, bend;
struct {
struct dentry *dentry;
struct inode *inode;
mode_t mode;
} orig_h, tmp_h;
struct au_hdentry *hd;
struct inode *inode, *h_inode;
struct dentry *h_dentry;
err = 0;
AuDebugOn(dinfo->di_bstart < 0);
orig_h.dentry = dinfo->di_hdentry[dinfo->di_bstart].hd_dentry;
orig_h.inode = orig_h.dentry->d_inode;
orig_h.mode = 0;
if (orig_h.inode)
orig_h.mode = orig_h.inode->i_mode & S_IFMT;
memset(&tmp_h, 0, sizeof(tmp_h));
if (tmp->di_bstart >= 0) {
tmp_h.dentry = tmp->di_hdentry[tmp->di_bstart].hd_dentry;
tmp_h.inode = tmp_h.dentry->d_inode;
if (tmp_h.inode)
tmp_h.mode = tmp_h.inode->i_mode & S_IFMT;
}
inode = dentry->d_inode;
if (!orig_h.inode) {
AuDbg("nagative originally\n");
if (inode) {
au_hide(dentry);
goto out;
}
AuDebugOn(inode);
AuDebugOn(dinfo->di_bstart != dinfo->di_bend);
AuDebugOn(dinfo->di_bdiropq != -1);
if (!tmp_h.inode) {
AuDbg("negative --> negative\n");
/* should have only one negative lower */
if (tmp->di_bstart >= 0
&& tmp->di_bstart < dinfo->di_bstart) {
AuDebugOn(tmp->di_bstart != tmp->di_bend);
AuDebugOn(dinfo->di_bstart != dinfo->di_bend);
au_set_h_dptr(dentry, dinfo->di_bstart, NULL);
au_di_cp(dinfo, tmp);
hd = tmp->di_hdentry + tmp->di_bstart;
au_set_h_dptr(dentry, tmp->di_bstart,
dget(hd->hd_dentry));
}
au_dbg_verify_dinode(dentry);
} else {
AuDbg("negative --> positive\n");
/*
* similar to the behaviour of creating with bypassing
* aufs.
* unhash it in order to force an error in the
* succeeding create operation.
* we should not set S_DEAD here.
*/
d_drop(dentry);
/* au_di_swap(tmp, dinfo); */
au_dbg_verify_dinode(dentry);
}
} else {
AuDbg("positive originally\n");
/* inode may be NULL */
AuDebugOn(inode && (inode->i_mode & S_IFMT) != orig_h.mode);
if (!tmp_h.inode) {
AuDbg("positive --> negative\n");
/* or bypassing aufs */
au_hide(dentry);
if (tmp->di_bwh >= 0 && tmp->di_bwh <= dinfo->di_bstart)
dinfo->di_bwh = tmp->di_bwh;
if (inode)
err = au_refresh_hinode_self(inode);
au_dbg_verify_dinode(dentry);
} else if (orig_h.mode == tmp_h.mode) {
AuDbg("positive --> positive, same type\n");
if (!S_ISDIR(orig_h.mode)
&& dinfo->di_bstart > tmp->di_bstart) {
/*
* similar to the behaviour of removing and
* creating.
*/
au_hide(dentry);
if (inode)
err = au_refresh_hinode_self(inode);
au_dbg_verify_dinode(dentry);
} else {
/* fill empty slots */
if (dinfo->di_bstart > tmp->di_bstart)
dinfo->di_bstart = tmp->di_bstart;
if (dinfo->di_bend < tmp->di_bend)
dinfo->di_bend = tmp->di_bend;
dinfo->di_bwh = tmp->di_bwh;
dinfo->di_bdiropq = tmp->di_bdiropq;
hd = tmp->di_hdentry;
bend = dinfo->di_bend;
for (bindex = tmp->di_bstart; bindex <= bend;
bindex++) {
if (au_h_dptr(dentry, bindex))
continue;
h_dentry = hd[bindex].hd_dentry;
if (!h_dentry)
continue;
h_inode = h_dentry->d_inode;
AuDebugOn(!h_inode);
AuDebugOn(orig_h.mode
!= (h_inode->i_mode
& S_IFMT));
au_set_h_dptr(dentry, bindex,
dget(h_dentry));
}
err = au_refresh_hinode(inode, dentry);
au_dbg_verify_dinode(dentry);
}
} else {
AuDbg("positive --> positive, different type\n");
/* similar to the behaviour of removing and creating */
au_hide(dentry);
if (inode)
err = au_refresh_hinode_self(inode);
au_dbg_verify_dinode(dentry);
}
}
out:
return err;
}