/* 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++;
}
int au_fhsm_fd(struct super_block *sb, int oflags)
{
int err, fd;
struct au_sbinfo *sbinfo;
struct au_fhsm *fhsm;
err = -EPERM;
if (unlikely(!capable(CAP_SYS_ADMIN)))
goto out;
err = -EINVAL;
if (unlikely(oflags & ~(O_CLOEXEC | O_NONBLOCK)))
goto out;
err = 0;
sbinfo = au_sbi(sb);
fhsm = &sbinfo->si_fhsm;
spin_lock(&fhsm->fhsm_spin);
if (!fhsm->fhsm_pid)
fhsm->fhsm_pid = current->pid;
else
err = -EBUSY;
spin_unlock(&fhsm->fhsm_spin);
if (unlikely(err))
goto out;
oflags |= O_RDONLY;
/* oflags |= FMODE_NONOTIFY; */
fd = anon_inode_getfd("[aufs_fhsm]", &au_fhsm_fops, sbinfo, oflags);
err = fd;
if (unlikely(fd < 0))
goto out_pid;
/* succeed reglardless 'fhsm' status */
kobject_get(&sbinfo->si_kobj);
si_noflush_read_lock(sb);
if (au_ftest_si(sbinfo, FHSM))
au_fhsm_wrote_all(sb, /*force*/0);
si_read_unlock(sb);
goto out; /* success */
out_pid:
spin_lock(&fhsm->fhsm_spin);
fhsm->fhsm_pid = 0;
spin_unlock(&fhsm->fhsm_spin);
out:
AuTraceErr(err);
return err;
}
/* it is ok that new 'nwt' tasks are appended while we are sleeping */
int si_read_lock(struct super_block *sb, int flags)
{
int err;
err = 0;
if (au_ftest_lock(flags, FLUSH))
au_nwt_flush(&au_sbi(sb)->si_nowait);
si_noflush_read_lock(sb);
err = au_plink_maint(sb, flags);
if (unlikely(err))
si_read_unlock(sb);
return err;
}
int au_do_flush(struct file *file, fl_owner_t id,
int (*flush)(struct file *file, fl_owner_t id))
{
int err;
struct dentry *dentry;
struct super_block *sb;
struct inode *inode;
dentry = file->f_dentry;
sb = dentry->d_sb;
inode = dentry->d_inode;
si_noflush_read_lock(sb);
fi_read_lock(file);
ii_read_lock_child(inode);
err = flush(file, id);
au_cpup_attr_timesizes(inode);
ii_read_unlock(inode);
fi_read_unlock(file);
si_read_unlock(sb);
return err;
}
/* common functions to regular file and dir */
struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
struct file *file)
{
struct file *h_file;
struct dentry *h_dentry;
struct inode *h_inode;
struct super_block *sb;
struct au_branch *br;
struct path h_path;
int err, exec_flag;
/* a race condition can happen between open and unlink/rmdir */
h_file = ERR_PTR(-ENOENT);
h_dentry = au_h_dptr(dentry, bindex);
if (au_test_nfsd() && !h_dentry)
goto out;
h_inode = h_dentry->d_inode;
if (au_test_nfsd() && !h_inode)
goto out;
spin_lock(&h_dentry->d_lock);
err = (!d_unhashed(dentry) && d_unlinked(h_dentry))
|| !h_inode
/* || !dentry->d_inode->i_nlink */
;
spin_unlock(&h_dentry->d_lock);
if (unlikely(err))
goto out;
sb = dentry->d_sb;
br = au_sbr(sb, bindex);
h_file = ERR_PTR(-EACCES);
exec_flag = flags & __FMODE_EXEC;
if (exec_flag && (br->br_mnt->mnt_flags & MNT_NOEXEC))
goto out;
/* drop flags for writing */
if (au_test_ro(sb, bindex, dentry->d_inode))
flags = au_file_roflags(flags);
flags &= ~O_CREAT;
atomic_inc(&br->br_count);
h_path.dentry = h_dentry;
h_path.mnt = br->br_mnt;
if (!au_special_file(h_inode->i_mode))
h_file = vfsub_dentry_open(&h_path, flags);
else {
/* this block depends upon the configuration */
di_read_unlock(dentry, AuLock_IR);
fi_write_unlock(file);
si_read_unlock(sb);
h_file = vfsub_dentry_open(&h_path, flags);
si_noflush_read_lock(sb);
fi_write_lock(file);
di_read_lock_child(dentry, AuLock_IR);
}
if (IS_ERR(h_file))
goto out_br;
if (exec_flag) {
err = deny_write_access(h_file);
if (unlikely(err)) {
fput(h_file);
h_file = ERR_PTR(err);
goto out_br;
}
}
fsnotify_open(h_file);
goto out; /* success */
out_br:
atomic_dec(&br->br_count);
out:
return h_file;
}
static int au_ready_to_write_wh(struct file *file, loff_t len,
aufs_bindex_t bcpup, struct au_pin *pin)
{
int err;
struct inode *inode, *h_inode;
struct dentry *h_dentry, *hi_wh;
struct au_cp_generic cpg = {
.dentry = file->f_dentry,
.bdst = bcpup,
.bsrc = -1,
.len = len,
.pin = pin
};
au_update_dbstart(cpg.dentry);
inode = cpg.dentry->d_inode;
h_inode = NULL;
if (au_dbstart(cpg.dentry) <= bcpup
&& au_dbend(cpg.dentry) >= bcpup) {
h_dentry = au_h_dptr(cpg.dentry, bcpup);
if (h_dentry)
h_inode = h_dentry->d_inode;
}
hi_wh = au_hi_wh(inode, bcpup);
if (!hi_wh && !h_inode)
err = au_sio_cpup_wh(&cpg, file);
else
/* already copied-up after unlink */
err = au_reopen_wh(file, bcpup, hi_wh);
if (!err
&& inode->i_nlink > 1
&& au_opt_test(au_mntflags(cpg.dentry->d_sb), PLINK))
au_plink_append(inode, bcpup, au_h_dptr(cpg.dentry, bcpup));
return err;
}
/*
* prepare the @file for writing.
*/
int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
{
int err;
aufs_bindex_t dbstart;
struct dentry *parent, *h_dentry;
struct inode *inode;
struct super_block *sb;
struct file *h_file;
struct au_cp_generic cpg = {
.dentry = file->f_dentry,
.bdst = -1,
.bsrc = -1,
.len = len,
.pin = pin,
.flags = AuCpup_DTIME
};
sb = cpg.dentry->d_sb;
inode = cpg.dentry->d_inode;
AuDebugOn(au_special_file(inode->i_mode));
cpg.bsrc = au_fbstart(file);
err = au_test_ro(sb, cpg.bsrc, inode);
if (!err && (au_hf_top(file)->f_mode & FMODE_WRITE)) {
err = au_pin(pin, cpg.dentry, cpg.bsrc, AuOpt_UDBA_NONE,
/*flags*/0);
goto out;
}
/* need to cpup or reopen */
parent = dget_parent(cpg.dentry);
di_write_lock_parent(parent);
err = AuWbrCopyup(au_sbi(sb), cpg.dentry);
cpg.bdst = err;
if (unlikely(err < 0))
goto out_dgrade;
err = 0;
if (!d_unhashed(cpg.dentry) && !au_h_dptr(parent, cpg.bdst)) {
err = au_cpup_dirs(cpg.dentry, cpg.bdst);
if (unlikely(err))
goto out_dgrade;
}
err = au_pin(pin, cpg.dentry, cpg.bdst, AuOpt_UDBA_NONE,
AuPin_DI_LOCKED | AuPin_MNT_WRITE);
if (unlikely(err))
goto out_dgrade;
h_dentry = au_hf_top(file)->f_dentry;
dbstart = au_dbstart(cpg.dentry);
if (dbstart <= cpg.bdst) {
h_dentry = au_h_dptr(cpg.dentry, cpg.bdst);
AuDebugOn(!h_dentry);
cpg.bsrc = cpg.bdst;
}
if (dbstart <= cpg.bdst /* just reopen */
|| !d_unhashed(cpg.dentry) /* copyup and reopen */
) {
h_file = au_h_open_pre(cpg.dentry, cpg.bsrc, /*force_wr*/0);
if (IS_ERR(h_file))
err = PTR_ERR(h_file);
else {
di_downgrade_lock(parent, AuLock_IR);
if (dbstart > cpg.bdst)
err = au_sio_cpup_simple(&cpg);
if (!err)
err = au_reopen_nondir(file);
au_h_open_post(cpg.dentry, cpg.bsrc, h_file);
}
} else { /* copyup as wh and reopen */
/*
* since writable hfsplus branch is not supported,
* h_open_pre/post() are unnecessary.
*/
err = au_ready_to_write_wh(file, len, cpg.bdst, pin);
di_downgrade_lock(parent, AuLock_IR);
}
if (!err) {
au_pin_set_parent_lflag(pin, /*lflag*/0);
goto out_dput; /* success */
}
au_unpin(pin);
goto out_unlock;
out_dgrade:
di_downgrade_lock(parent, AuLock_IR);
out_unlock:
di_read_unlock(parent, AuLock_IR);
out_dput:
dput(parent);
out:
return err;
}
/* ---------------------------------------------------------------------- */
int au_do_flush(struct file *file, fl_owner_t id,
int (*flush)(struct file *file, fl_owner_t id))
{
int err;
struct super_block *sb;
struct inode *inode;
inode = file_inode(file);
sb = inode->i_sb;
si_noflush_read_lock(sb);
fi_read_lock(file);
ii_read_lock_child(inode);
err = flush(file, id);
au_cpup_attr_timesizes(inode);
ii_read_unlock(inode);
fi_read_unlock(file);
si_read_unlock(sb);
return err;
}