/* todo: file size may exceed PAGE_SIZE */
ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
ssize_t err;
long l;
aufs_bindex_t bend;
struct au_sbinfo *sbinfo;
struct super_block *sb;
struct seq_file *seq;
char *name;
struct attribute **cattr;
sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
sb = sbinfo->si_sb;
si_noflush_read_lock(sb);
seq = au_seq(buf, PAGE_SIZE);
err = PTR_ERR(seq);
if (IS_ERR(seq))
goto out;
name = (void *)attr->name;
cattr = sysaufs_si_attrs;
while (*cattr) {
if (!strcmp(name, (*cattr)->name)) {
err = container_of(*cattr, struct sysaufs_si_attr, attr)
->show(seq, sb);
goto out_seq;
}
cattr++;
}
/* todo: file size may exceed PAGE_SIZE */
ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
ssize_t err;
int idx;
long l;
aufs_bindex_t bend;
struct au_sbinfo *sbinfo;
struct super_block *sb;
struct seq_file *seq;
char *name;
struct attribute **cattr;
sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
sb = sbinfo->si_sb;
/*
* prevent a race condition between sysfs and aufs.
* for instance, sysfs_file_read() calls sysfs_get_active_two() which
* prohibits maintaining the sysfs entries.
* hew we acquire read lock after sysfs_get_active_two().
* on the other hand, the remount process may maintain the sysfs/aufs
* entries after acquiring write lock.
* it can cause a deadlock.
* simply we gave up processing read here.
*/
err = -EBUSY;
if (unlikely(!si_noflush_read_trylock(sb)))
goto out;
seq = au_seq(buf, PAGE_SIZE);
err = PTR_ERR(seq);
if (IS_ERR(seq))
goto out_unlock;
name = (void *)attr->name;
cattr = sysaufs_si_attrs;
while (*cattr) {
if (!strcmp(name, (*cattr)->name)) {
err = container_of(*cattr, struct sysaufs_si_attr, attr)
->show(seq, sb);
goto out_seq;
}
cattr++;
}
