/* 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 (sigen != au_digen(dentry)
|| sigen != au_iigen(inode)) {
err = au_reval_dpath(dentry, sigen);
if (unlikely(err < 0))
goto out;
AuDebugOn(au_digen(dentry) != sigen
|| au_iigen(inode) != sigen);
}
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;
}
void au_finfo_fin(struct file *file)
{
struct au_finfo *finfo;
aufs_bindex_t bindex, bend;
fi_write_lock(file);
bend = au_fbend(file);
bindex = au_fbstart(file);
if (bindex >= 0)
/*
* calls fput() instead of filp_close(),
* since no dnotify or lock for the lower file.
*/
for (; bindex <= bend; bindex++)
au_set_h_fptr(file, bindex, NULL);
finfo = au_fi(file);
au_dbg_verify_hf(finfo);
kfree(finfo->fi_hfile);
fi_write_unlock(file);
AuRwDestroy(&finfo->fi_rwsem);
au_cache_free_finfo(finfo);
}
/* 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;
}
