static ssize_t au_fhsm_read(struct file *file, char __user *buf, size_t count,
loff_t *pos)
{
ssize_t err;
int readable;
aufs_bindex_t nfhsm, bindex, bend;
struct au_sbinfo *sbinfo;
struct au_fhsm *fhsm;
struct au_branch *br;
struct super_block *sb;
err = 0;
sbinfo = file->private_data;
fhsm = &sbinfo->si_fhsm;
need_data:
spin_lock_irq(&fhsm->fhsm_wqh.lock);
if (!atomic_read(&fhsm->fhsm_readable)) {
if (vfsub_file_flags(file) & O_NONBLOCK)
err = -EAGAIN;
else
err = wait_event_interruptible_locked_irq
(fhsm->fhsm_wqh,
atomic_read(&fhsm->fhsm_readable));
}
spin_unlock_irq(&fhsm->fhsm_wqh.lock);
if (unlikely(err))
goto out;
/* sb may already be dead */
au_rw_read_lock(&sbinfo->si_rwsem);
readable = atomic_read(&fhsm->fhsm_readable);
if (readable > 0) {
sb = sbinfo->si_sb;
AuDebugOn(!sb);
/* exclude the bottom branch */
nfhsm = 0;
bend = au_fhsm_bottom(sb);
for (bindex = 0; bindex < bend; bindex++) {
br = au_sbr(sb, bindex);
if (au_br_fhsm(br->br_perm))
nfhsm++;
}
err = -EMSGSIZE;
if (nfhsm * sizeof(struct aufs_stbr) <= count) {
atomic_set(&fhsm->fhsm_readable, 0);
err = au_fhsm_do_read(sbinfo->si_sb, (void __user *)buf,
count);
}
}
au_rw_read_unlock(&sbinfo->si_rwsem);
if (!readable)
goto need_data;
out:
return err;
}
void di_read_unlock(struct dentry *d, int flags)
{
if (d->d_inode) {
if (au_ftest_lock(flags, IW))
ii_write_unlock(d->d_inode);
else if (au_ftest_lock(flags, IR))
ii_read_unlock(d->d_inode);
}
au_rw_read_unlock(&au_di(d)->di_rwsem);
}
void di_read_unlock(struct dentry *d, int flags)
{
if (d->d_inode) {
if (au_ftest_lock(flags, IW)) {
au_dbg_verify_dinode(d);
ii_write_unlock(d->d_inode);
} else if (au_ftest_lock(flags, IR)) {
au_dbg_verify_dinode(d);
ii_read_unlock(d->d_inode);
}
}
au_rw_read_unlock(&au_di(d)->di_rwsem);
}
void di_read_unlock(struct dentry *d, int flags)
{
LKTRTrace("%.*s\n", AuDLNPair(d));
SiMustAnyLock(d->d_sb);
if (d->d_inode) {
if (au_ftest_lock(flags, IW))
ii_write_unlock(d->d_inode);
else if (au_ftest_lock(flags, IR))
ii_read_unlock(d->d_inode);
}
au_rw_read_unlock(&au_di(d)->di_rwsem);
au_dbg_locked_di_unreg(d, flags);
}