int au_digen_test(struct dentry *dentry, unsigned int sigen) { int err; err = 0; if (unlikely(au_digen(dentry) != sigen || au_iigen_test(dentry->d_inode, sigen))) err = -EIO; return err; }
static int aufs_permission(struct inode *inode, int mask) { int err; aufs_bindex_t bindex, bend; const unsigned char isdir = !!S_ISDIR(inode->i_mode), write_mask = !!(mask & (MAY_WRITE | MAY_APPEND)); struct inode *h_inode; struct super_block *sb; struct au_branch *br; /* todo: support rcu-walk? */ if (mask & MAY_NOT_BLOCK) return -ECHILD; sb = inode->i_sb; si_read_lock(sb, AuLock_FLUSH); ii_read_lock_child(inode); #if 0 err = au_iigen_test(inode, au_sigen(sb)); if (unlikely(err)) goto out; #endif if (!isdir || write_mask) { err = au_busy_or_stale(); h_inode = au_h_iptr(inode, au_ibstart(inode)); if (unlikely(!h_inode || (h_inode->i_mode & S_IFMT) != (inode->i_mode & S_IFMT))) goto out; err = 0; bindex = au_ibstart(inode); br = au_sbr(sb, bindex); err = h_permission(h_inode, mask, br->br_mnt, br->br_perm); if (write_mask && !err && !special_file(h_inode->i_mode)) { /* test whether the upper writable branch exists */ err = -EROFS; for (; bindex >= 0; bindex--) if (!au_br_rdonly(au_sbr(sb, bindex))) { err = 0; break; } } goto out; } /* non-write to dir */ err = 0; bend = au_ibend(inode); for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) { h_inode = au_h_iptr(inode, bindex); if (h_inode) { err = au_busy_or_stale(); if (unlikely(!S_ISDIR(h_inode->i_mode))) break; br = au_sbr(sb, bindex); err = h_permission(h_inode, mask, br->br_mnt, br->br_perm); } } out: ii_read_unlock(inode); si_read_unlock(sb); return err; }