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, DIR));
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;
}
/* common function to regular file and dir */
int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
int wlock)
{
int err;
unsigned int sigen, figen;
aufs_bindex_t bstart;
unsigned char pseudo_link;
struct dentry *dentry;
struct inode *inode;
err = 0;
dentry = file->f_dentry;
inode = dentry->d_inode;
AuDebugOn(au_special_file(inode->i_mode));
sigen = au_sigen(dentry->d_sb);
fi_write_lock(file);
figen = au_figen(file);
di_write_lock_child(dentry);
bstart = au_dbstart(dentry);
pseudo_link = (bstart != au_ibstart(inode));
if (sigen == figen && !pseudo_link && au_fbstart(file) == bstart) {
if (!wlock) {
di_downgrade_lock(dentry, AuLock_IR);
fi_downgrade_lock(file);
}
goto out; /* success */
}
AuDbg("sigen %d, figen %d\n", sigen, figen);
if (au_digen_test(dentry, sigen)) {
err = au_reval_dpath(dentry, sigen);
AuDebugOn(!err && au_digen_test(dentry, sigen));
}
if (!err)
err = refresh_file(file, reopen);
if (!err) {
if (!wlock) {
di_downgrade_lock(dentry, AuLock_IR);
fi_downgrade_lock(file);
}
} else {
di_write_unlock(dentry);
fi_write_unlock(file);
}
out:
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));
AuDebugOn(!err && au_dbrange_test(dentry));
if (unlikely(err))
aufs_read_unlock(dentry, flags);
}
out:
return err;
}
int au_reval_dpath(struct dentry *dentry, unsigned int sigen)
{
int err;
struct dentry *d, *parent;
struct inode *inode;
if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIR))
return simple_reval_dpath(dentry, sigen);
/* slow loop, keep it simple and stupid */
/* cf: au_cpup_dirs() */
err = 0;
parent = NULL;
while (au_digen_test(dentry, sigen)) {
d = dentry;
while (1) {
dput(parent);
parent = dget_parent(d);
if (!au_digen_test(parent, sigen))
break;
d = parent;
}
inode = d->d_inode;
if (d != dentry)
di_write_lock_child2(d);
/* someone might update our dentry while we were sleeping */
if (au_digen_test(d, sigen)) {
/*
* todo: consolidate with simple_reval_dpath(),
* do_refresh() and au_reval_for_attr().
*/
di_read_lock_parent(parent, AuLock_IR);
err = au_refresh_dentry(d, parent);
di_read_unlock(parent, AuLock_IR);
}
if (d != dentry)
di_write_unlock(d);
dput(parent);
if (unlikely(err))
break;
}
return err;
}
/* todo: consolidate with do_refresh() and au_reval_for_attr() */
static int simple_reval_dpath(struct dentry *dentry, unsigned int sigen)
{
int err;
struct dentry *parent;
if (!au_digen_test(dentry, sigen))
return 0;
parent = dget_parent(dentry);
di_read_lock_parent(parent, AuLock_IR);
AuDebugOn(au_digen_test(parent, sigen));
au_dbg_verify_gen(parent, sigen);
err = au_refresh_dentry(dentry, parent);
di_read_unlock(parent, AuLock_IR);
dput(parent);
AuTraceErr(err);
return err;
}
void au_dbg_verify_dir_parent(struct dentry *dentry, unsigned int sigen)
{
struct dentry *parent;
parent = dget_parent(dentry);
AuDebugOn(!S_ISDIR(dentry->d_inode->i_mode));
AuDebugOn(IS_ROOT(dentry));
AuDebugOn(au_digen_test(parent, sigen));
dput(parent);
}
void au_dbg_verify_nondir_parent(struct dentry *dentry, unsigned int sigen)
{
struct dentry *parent;
struct inode *inode;
parent = dget_parent(dentry);
inode = dentry->d_inode;
AuDebugOn(inode && S_ISDIR(dentry->d_inode->i_mode));
AuDebugOn(au_digen_test(parent, sigen));
dput(parent);
}
void au_dbg_verify_gen(struct dentry *parent, unsigned int sigen)
{
int err, i, j;
struct au_dcsub_pages dpages;
struct au_dpage *dpage;
struct dentry **dentries;
err = au_dpages_init(&dpages, GFP_NOFS);
AuDebugOn(err);
err = au_dcsub_pages_rev_aufs(&dpages, parent, /*do_include*/1);
AuDebugOn(err);
for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
dpage = dpages.dpages + i;
dentries = dpage->dentries;
for (j = dpage->ndentry - 1; !err && j >= 0; j--)
AuDebugOn(au_digen_test(dentries[j], sigen));
}
au_dpages_free(&dpages);
}
/* todo: consolidate with do_refresh() and simple_reval_dpath() */
static int au_reval_for_attr(struct dentry *dentry, unsigned int sigen)
{
int err;
struct inode *inode;
struct dentry *parent;
err = 0;
inode = dentry->d_inode;
if (au_digen_test(dentry, sigen)) {
parent = dget_parent(dentry);
di_read_lock_parent(parent, AuLock_IR);
err = au_refresh_dentry(dentry, parent);
di_read_unlock(parent, AuLock_IR);
dput(parent);
}
AuTraceErr(err);
return err;
}
static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct dentry *ret, *parent;
struct inode *inode;
struct super_block *sb;
int err, npositive, lc_idx;
IMustLock(dir);
sb = dir->i_sb;
err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
ret = ERR_PTR(err);
if (unlikely(err))
goto out;
ret = ERR_PTR(-ENAMETOOLONG);
if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
goto out_si;
err = au_di_init(dentry);
ret = ERR_PTR(err);
if (unlikely(err))
goto out_si;
inode = NULL;
npositive = 0; /* suppress a warning */
parent = dentry->d_parent; /* dir inode is locked */
di_read_lock_parent(parent, AuLock_IR);
err = au_alive_dir(parent);
if (!err)
err = au_digen_test(parent, au_sigen(sb));
if (!err) {
npositive = au_lkup_dentry(dentry, au_dbstart(parent),
/*type*/0, nd);
err = npositive;
}
di_read_unlock(parent, AuLock_IR);
ret = ERR_PTR(err);
if (unlikely(err < 0))
goto out_unlock;
if (npositive) {
inode = au_new_inode(dentry, /*must_new*/0);
ret = (void *)inode;
}
if (IS_ERR(inode)) {
inode = NULL;
goto out_unlock;
}
ret = d_splice_alias(inode, dentry);
if (unlikely(IS_ERR(ret) && inode)) {
ii_write_unlock(inode);
lc_idx = AuLcNonDir_IIINFO;
if (S_ISLNK(inode->i_mode))
lc_idx = AuLcSymlink_IIINFO;
else if (S_ISDIR(inode->i_mode))
lc_idx = AuLcDir_IIINFO;
au_rw_class(&au_ii(inode)->ii_rwsem, au_lc_key + lc_idx);
iput(inode);
}
out_unlock:
di_write_unlock(dentry);
if (unlikely(IS_ERR(ret) && inode)) {
lc_idx = AuLcNonDir_DIINFO;
if (S_ISLNK(inode->i_mode))
lc_idx = AuLcSymlink_DIINFO;
else if (S_ISDIR(inode->i_mode))
lc_idx = AuLcDir_DIINFO;
au_rw_class(&au_di(dentry)->di_rwsem, au_lc_key + lc_idx);
}
out_si:
si_read_unlock(sb);
out:
return ret;
}
int au_refresh_dentry(struct dentry *dentry, struct dentry *parent)
{
int err, ebrange;
unsigned int sigen;
struct au_dinfo *dinfo, *tmp;
struct super_block *sb;
struct inode *inode;
DiMustWriteLock(dentry);
AuDebugOn(IS_ROOT(dentry));
AuDebugOn(!parent->d_inode);
sb = dentry->d_sb;
inode = dentry->d_inode;
sigen = au_sigen(sb);
err = au_digen_test(parent, sigen);
if (unlikely(err))
goto out;
dinfo = au_di(dentry);
err = au_di_realloc(dinfo, au_sbend(sb) + 1);
if (unlikely(err))
goto out;
ebrange = au_dbrange_test(dentry);
if (!ebrange)
ebrange = au_do_refresh_hdentry(dentry, parent);
if (d_unhashed(dentry) || ebrange) {
AuDebugOn(au_dbstart(dentry) < 0 && au_dbend(dentry) >= 0);
if (inode)
err = au_refresh_hinode_self(inode);
au_dbg_verify_dinode(dentry);
if (!err)
goto out_dgen; /* success */
goto out;
}
/* temporary dinfo */
AuDbgDentry(dentry);
err = -ENOMEM;
tmp = au_di_alloc(sb, AuLsc_DI_TMP);
if (unlikely(!tmp))
goto out;
au_di_swap(tmp, dinfo);
/* returns the number of positive dentries */
/*
* if current working dir is removed, it returns an error.
* but the dentry is legal.
*/
err = au_lkup_dentry(dentry, /*bstart*/0, /*type*/0, /*nd*/NULL);
AuDbgDentry(dentry);
au_di_swap(tmp, dinfo);
if (err == -ENOENT)
err = 0;
if (err >= 0) {
/* compare/refresh by dinfo */
AuDbgDentry(dentry);
err = au_refresh_by_dinfo(dentry, dinfo, tmp);
au_dbg_verify_dinode(dentry);
AuTraceErr(err);
}
au_rw_write_unlock(&tmp->di_rwsem);
au_di_free(tmp);
if (unlikely(err))
goto out;
out_dgen:
au_update_digen(dentry);
out:
if (unlikely(err && !(dentry->d_flags & DCACHE_NFSFS_RENAMED))) {
AuIOErr("failed refreshing %.*s, %d\n",
AuDLNPair(dentry), err);
AuDbgDentry(dentry);
}
AuTraceErr(err);
return err;
}
/*
* if valid returns 1, otherwise 0.
*/
static int aufs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
int valid, err;
unsigned int sigen;
unsigned char do_udba;
struct super_block *sb;
struct inode *inode;
valid = 0;
if (unlikely(!au_di(dentry)))
goto out;
valid = 1;
sb = dentry->d_sb;
inode = dentry->d_inode;
/*
* todo: very ugly
* i_mutex of parent dir may be held,
* but we should not return 'invalid' due to busy.
*/
err = aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW | AuLock_NOPLM);
if (unlikely(err)) {
valid = err;
AuTraceErr(err);
goto out;
}
if (unlikely(au_dbrange_test(dentry))) {
err = -EINVAL;
AuTraceErr(err);
goto out_dgrade;
}
sigen = au_sigen(sb);
if (au_digen_test(dentry, sigen)) {
AuDebugOn(IS_ROOT(dentry));
err = au_reval_dpath(dentry, sigen);
if (unlikely(err)) {
AuTraceErr(err);
goto out_dgrade;
}
}
di_downgrade_lock(dentry, AuLock_IR);
err = -EINVAL;
if (inode && (IS_DEADDIR(inode) || !inode->i_nlink))
goto out_inval;
do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
if (do_udba && inode) {
aufs_bindex_t bstart = au_ibstart(inode);
struct inode *h_inode;
if (bstart >= 0) {
h_inode = au_h_iptr(inode, bstart);
if (h_inode && au_test_higen(inode, h_inode))
goto out_inval;
}
}
err = h_d_revalidate(dentry, inode, nd, do_udba);
if (unlikely(!err && do_udba && au_dbstart(dentry) < 0)) {
err = -EIO;
AuDbg("both of real entry and whiteout found, %.*s, err %d\n",
AuDLNPair(dentry), err);
}
goto out_inval;
out_dgrade:
di_downgrade_lock(dentry, AuLock_IR);
out_inval:
aufs_read_unlock(dentry, AuLock_IR);
AuTraceErr(err);
valid = !err;
out:
if (!valid) {
AuDbg("%.*s invalid, %d\n", AuDLNPair(dentry), valid);
d_drop(dentry);
}
return valid;
}
/*
* if valid returns 1, otherwise 0.
*/
static int aufs_d_revalidate(struct dentry *dentry, unsigned int flags)
{
int valid, err;
unsigned int sigen;
unsigned char do_udba;
struct super_block *sb;
struct inode *inode;
/* todo: support rcu-walk? */
if (flags & LOOKUP_RCU)
return -ECHILD;
valid = 0;
if (unlikely(!au_di(dentry)))
goto out;
valid = 1;
sb = dentry->d_sb;
/*
* todo: very ugly
* i_mutex of parent dir may be held,
* but we should not return 'invalid' due to busy.
*/
err = aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW | AuLock_NOPLM);
if (unlikely(err)) {
valid = err;
AuTraceErr(err);
goto out;
}
inode = NULL;
if (d_really_is_positive(dentry))
inode = d_inode(dentry);
if (unlikely(inode && is_bad_inode(inode))) {
err = -EINVAL;
AuTraceErr(err);
goto out_dgrade;
}
if (unlikely(au_dbrange_test(dentry))) {
err = -EINVAL;
AuTraceErr(err);
goto out_dgrade;
}
sigen = au_sigen(sb);
if (au_digen_test(dentry, sigen)) {
AuDebugOn(IS_ROOT(dentry));
err = au_reval_dpath(dentry, sigen);
if (unlikely(err)) {
AuTraceErr(err);
goto out_dgrade;
}
}
di_downgrade_lock(dentry, AuLock_IR);
err = -EINVAL;
if (!(flags & (LOOKUP_OPEN | LOOKUP_EMPTY))
&& inode
&& !(inode->i_state && I_LINKABLE)
&& (IS_DEADDIR(inode) || !inode->i_nlink))
goto out_inval;
do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
if (do_udba && inode) {
aufs_bindex_t bstart = au_ibstart(inode);
struct inode *h_inode;
if (bstart >= 0) {
h_inode = au_h_iptr(inode, bstart);
if (h_inode && au_test_higen(inode, h_inode))
goto out_inval;
}
}
err = h_d_revalidate(dentry, inode, flags, do_udba);
if (unlikely(!err && do_udba && au_dbstart(dentry) < 0)) {
err = -EIO;
AuDbg("both of real entry and whiteout found, %p, err %d\n",
dentry, err);
}
goto out_inval;
out_dgrade:
di_downgrade_lock(dentry, AuLock_IR);
out_inval:
aufs_read_unlock(dentry, AuLock_IR);
AuTraceErr(err);
valid = !err;
out:
if (!valid) {
AuDbg("%pd invalid, %d\n", dentry, valid);
d_drop(dentry);
}
return valid;
}
/*
* test if the branch is deletable or not.
*/
static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
unsigned int sigen, const unsigned int verbose)
{
int err, i, j, ndentry;
aufs_bindex_t bstart, bend;
struct au_dcsub_pages dpages;
struct au_dpage *dpage;
struct dentry *d;
err = au_dpages_init(&dpages, GFP_NOFS);
if (unlikely(err))
goto out;
err = au_dcsub_pages(&dpages, root, NULL, NULL);
if (unlikely(err))
goto out_dpages;
for (i = 0; !err && i < dpages.ndpage; i++) {
dpage = dpages.dpages + i;
ndentry = dpage->ndentry;
for (j = 0; !err && j < ndentry; j++) {
d = dpage->dentries[j];
AuDebugOn(!atomic_read(&d->d_count));
if (!au_digen_test(d, sigen)) {
di_read_lock_child(d, AuLock_IR);
if (unlikely(au_dbrange_test(d))) {
di_read_unlock(d, AuLock_IR);
continue;
}
} else {
di_write_lock_child(d);
if (unlikely(au_dbrange_test(d))) {
di_write_unlock(d);
continue;
}
err = au_reval_dpath(d, sigen);
if (!err)
di_downgrade_lock(d, AuLock_IR);
else {
di_write_unlock(d);
break;
}
}
/* AuDbgDentry(d); */
bstart = au_dbstart(d);
bend = au_dbend(d);
if (bstart <= bindex
&& bindex <= bend
&& au_h_dptr(d, bindex)
&& au_test_dbusy(d, bstart, bend)) {
err = -EBUSY;
AuVerbose(verbose, "busy %.*s\n", AuDLNPair(d));
AuDbgDentry(d);
}
di_read_unlock(d, AuLock_IR);
}
}
out_dpages:
au_dpages_free(&dpages);
out:
return err;
}
static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct dentry *ret, *parent;
struct inode *inode;
struct super_block *sb;
int err, npositive;
IMustLock(dir);
/* todo: support rcu-walk? */
ret = ERR_PTR(-ECHILD);
if (flags & LOOKUP_RCU)
goto out;
ret = ERR_PTR(-ENAMETOOLONG);
if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
goto out;
sb = dir->i_sb;
err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
ret = ERR_PTR(err);
if (unlikely(err))
goto out;
err = au_di_init(dentry);
ret = ERR_PTR(err);
if (unlikely(err))
goto out_si;
inode = NULL;
npositive = 0; /* suppress a warning */
parent = dentry->d_parent; /* dir inode is locked */
di_read_lock_parent(parent, AuLock_IR);
err = au_alive_dir(parent);
if (!err)
err = au_digen_test(parent, au_sigen(sb));
if (!err) {
/* regardless LOOKUP_CREATE, always ALLOW_NEG */
npositive = au_lkup_dentry(dentry, au_dbtop(parent),
AuLkup_ALLOW_NEG);
err = npositive;
}
di_read_unlock(parent, AuLock_IR);
ret = ERR_PTR(err);
if (unlikely(err < 0))
goto out_unlock;
if (npositive) {
inode = au_new_inode(dentry, /*must_new*/0);
if (IS_ERR(inode)) {
ret = (void *)inode;
inode = NULL;
goto out_unlock;
}
}
if (inode)
atomic_inc(&inode->i_count);
ret = d_splice_alias(inode, dentry);
#if 0
if (unlikely(d_need_lookup(dentry))) {
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
spin_unlock(&dentry->d_lock);
} else
#endif
if (inode) {
if (!IS_ERR(ret)) {
iput(inode);
if (ret && ret != dentry)
ii_write_unlock(inode);
} else {
ii_write_unlock(inode);
iput(inode);
inode = NULL;
}
}
out_unlock:
di_write_unlock(dentry);
out_si:
si_read_unlock(sb);
out:
return ret;
}
static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct dentry *ret, *parent;
struct inode *inode;
struct super_block *sb;
int err, npositive;
IMustLock(dir);
/* todo: support rcu-walk? */
ret = ERR_PTR(-ECHILD);
if (flags & LOOKUP_RCU)
goto out;
ret = ERR_PTR(-ENAMETOOLONG);
if (unlikely(dentry->d_name.len > AUFS_MAX_NAMELEN))
goto out;
sb = dir->i_sb;
err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM);
ret = ERR_PTR(err);
if (unlikely(err))
goto out;
err = au_di_init(dentry);
ret = ERR_PTR(err);
if (unlikely(err))
goto out_si;
inode = NULL;
npositive = 0; /* suppress a warning */
parent = dentry->d_parent; /* dir inode is locked */
di_read_lock_parent(parent, AuLock_IR);
err = au_alive_dir(parent);
if (!err)
err = au_digen_test(parent, au_sigen(sb));
if (!err) {
npositive = au_lkup_dentry(dentry, au_dbstart(parent),
/*type*/0);
err = npositive;
}
di_read_unlock(parent, AuLock_IR);
ret = ERR_PTR(err);
if (unlikely(err < 0))
goto out_unlock;
if (npositive) {
inode = au_new_inode(dentry, /*must_new*/0);
if (IS_ERR(inode)) {
ret = (void *)inode;
inode = NULL;
goto out_unlock;
}
}
if (inode)
atomic_inc(&inode->i_count);
ret = d_splice_alias(inode, dentry);
#if 0
if (unlikely(d_need_lookup(dentry))) {
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
spin_unlock(&dentry->d_lock);
} else
#endif
if (inode) {
if (!IS_ERR(ret)) {
iput(inode);
if (ret && ret != dentry)
ii_write_unlock(inode);
} else {
ii_write_unlock(inode);
iput(inode);
inode = NULL;
}
}
out_unlock:
di_write_unlock(dentry);
if (inode) {
/* verbose coding for lock class name */
if (unlikely(S_ISLNK(inode->i_mode)))
au_rw_class(&au_di(dentry)->di_rwsem,
au_lc_key + AuLcSymlink_DIINFO);
else if (unlikely(S_ISDIR(inode->i_mode)))
au_rw_class(&au_di(dentry)->di_rwsem,
au_lc_key + AuLcDir_DIINFO);
else /* likely */
au_rw_class(&au_di(dentry)->di_rwsem,
au_lc_key + AuLcNonDir_DIINFO);
}
out_si:
si_read_unlock(sb);
out:
return ret;
}