/* * unionfs_lookup is the only special function which takes a dentry, yet we * do NOT want to call __unionfs_d_revalidate_chain because by definition, * we don't have a valid dentry here yet. */ static struct dentry *unionfs_lookup(struct inode *dir, struct dentry *dentry, /* XXX: pass flags to lower? */ unsigned int flags_unused) { struct dentry *ret, *parent; int err = 0; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); /* * As long as we lock/dget the parent, then can skip validating the * parent now; we may have to rebuild this dentry on the next * ->d_revalidate, however. */ /* allocate dentry private data. We free it in ->d_release */ err = new_dentry_private_data(dentry, UNIONFS_DMUTEX_CHILD); if (unlikely(err)) { ret = ERR_PTR(err); goto out; } ret = unionfs_lookup_full(dentry, parent, INTERPOSE_LOOKUP); if (!IS_ERR(ret)) { if (ret) dentry = ret; /* lookup_full can return multiple positive dentries */ if (dentry->d_inode && !S_ISDIR(dentry->d_inode->i_mode)) { BUG_ON(dbstart(dentry) < 0); unionfs_postcopyup_release(dentry); } unionfs_copy_attr_times(dentry->d_inode); } unionfs_check_inode(dir); if (!IS_ERR(ret)) unionfs_check_dentry(dentry); unionfs_check_dentry(parent); unionfs_unlock_dentry(dentry); /* locked in new_dentry_private data */ out: unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return ret; }
/* * Copy up a dentry to a file of specified name. * * @dir: used to pull the ->i_sb to access other branches * @dentry: the non-negative dentry whose lower_inode we should copy * @bstart: the branch of the lower_inode to copy from * @new_bindex: the branch to create the new file in * @name: the name of the file to create * @namelen: length of @name * @copyup_file: the "struct file" to return (optional) * @len: how many bytes to copy-up? */ int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart, int new_bindex, const char *name, int namelen, struct file **copyup_file, loff_t len) { struct dentry *new_lower_dentry; struct dentry *old_lower_dentry = NULL; struct super_block *sb; int err = 0; int old_bindex; int old_bstart; int old_bend; struct dentry *new_lower_parent_dentry = NULL; mm_segment_t oldfs; char *symbuf = NULL; verify_locked(dentry); old_bindex = bstart; old_bstart = dbstart(dentry); old_bend = dbend(dentry); BUG_ON(new_bindex < 0); BUG_ON(new_bindex >= old_bindex); sb = dir->i_sb; err = is_robranch_super(sb, new_bindex); if (err) goto out; /* Create the directory structure above this dentry. */ new_lower_dentry = create_parents(dir, dentry, name, new_bindex); if (IS_ERR(new_lower_dentry)) { err = PTR_ERR(new_lower_dentry); goto out; } old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex); /* we conditionally dput this old_lower_dentry at end of function */ dget(old_lower_dentry); /* For symlinks, we must read the link before we lock the directory. */ if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) { symbuf = kmalloc(PATH_MAX, GFP_KERNEL); if (unlikely(!symbuf)) { __clear(dentry, old_lower_dentry, old_bstart, old_bend, new_lower_dentry, new_bindex); err = -ENOMEM; goto out_free; } oldfs = get_fs(); set_fs(KERNEL_DS); err = old_lower_dentry->d_inode->i_op->readlink( old_lower_dentry, (char __user *)symbuf, PATH_MAX); set_fs(oldfs); if (err < 0) { __clear(dentry, old_lower_dentry, old_bstart, old_bend, new_lower_dentry, new_bindex); goto out_free; } symbuf[err] = '\0'; } /* Now we lock the parent, and create the object in the new branch. */ new_lower_parent_dentry = lock_parent(new_lower_dentry); /* create the new inode */ err = __copyup_ndentry(old_lower_dentry, new_lower_dentry, new_lower_parent_dentry, symbuf); if (err) { __clear(dentry, old_lower_dentry, old_bstart, old_bend, new_lower_dentry, new_bindex); goto out_unlock; } /* We actually copyup the file here. */ if (S_ISREG(old_lower_dentry->d_inode->i_mode)) err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex, old_lower_dentry, old_bindex, copyup_file, len); if (err) goto out_unlink; /* Set permissions. */ err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry); if (err) goto out_unlink; #ifdef CONFIG_UNION_FS_XATTR /* Selinux uses extended attributes for permissions. */ err = copyup_xattrs(old_lower_dentry, new_lower_dentry); if (err) goto out_unlink; #endif /* CONFIG_UNION_FS_XATTR */ /* do not allow files getting deleted to be re-interposed */ if (!d_deleted(dentry)) unionfs_reinterpose(dentry); goto out_unlock; out_unlink: /* * copyup failed, because we possibly ran out of space or * quota, or something else happened so let's unlink; we don't * really care about the return value of vfs_unlink */ vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry); if (copyup_file) { /* need to close the file */ fput(*copyup_file); branchput(sb, new_bindex); } /* * TODO: should we reset the error to something like -EIO? * * If we don't reset, the user may get some nonsensical errors, but * on the other hand, if we reset to EIO, we guarantee that the user * will get a "confusing" error message. */ out_unlock: unlock_dir(new_lower_parent_dentry); out_free: /* * If old_lower_dentry was not a file, then we need to dput it. If * it was a file, then it was already dput indirectly by other * functions we call above which operate on regular files. */ if (old_lower_dentry && old_lower_dentry->d_inode && !S_ISREG(old_lower_dentry->d_inode->i_mode)) dput(old_lower_dentry); kfree(symbuf); if (err) { /* * if directory creation succeeded, but inode copyup failed, * then purge new dentries. */ if (dbstart(dentry) < old_bstart && ibstart(dentry->d_inode) > dbstart(dentry)) __clear(dentry, NULL, old_bstart, old_bend, unionfs_lower_dentry(dentry), dbstart(dentry)); goto out; } if (!S_ISDIR(dentry->d_inode->i_mode)) { unionfs_postcopyup_release(dentry); if (!unionfs_lower_inode(dentry->d_inode)) { /* * If we got here, then we copied up to an * unlinked-open file, whose name is .unionfsXXXXX. */ struct inode *inode = new_lower_dentry->d_inode; atomic_inc(&inode->i_count); unionfs_set_lower_inode_idx(dentry->d_inode, ibstart(dentry->d_inode), inode); } } unionfs_postcopyup_setmnt(dentry); /* sync inode times from copied-up inode to our inode */ unionfs_copy_attr_times(dentry->d_inode); unionfs_check_inode(dir); unionfs_check_dentry(dentry); out: return err; }
/* * The locking rules in unionfs_rename are complex. We could use a simpler * superblock-level name-space lock for renames and copy-ups. */ int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { int err = 0; struct dentry *wh_dentry; struct dentry *old_parent, *new_parent; int valid = true; unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD); old_parent = dget_parent(old_dentry); new_parent = dget_parent(new_dentry); /* un/lock parent dentries only if they differ from old/new_dentry */ if (old_parent != old_dentry && old_parent != new_dentry) unionfs_lock_dentry(old_parent, UNIONFS_DMUTEX_REVAL_PARENT); if (new_parent != old_dentry && new_parent != new_dentry && new_parent != old_parent) unionfs_lock_dentry(new_parent, UNIONFS_DMUTEX_REVAL_CHILD); unionfs_double_lock_dentry(old_dentry, new_dentry); valid = __unionfs_d_revalidate(old_dentry, old_parent, false); if (!valid) { err = -ESTALE; goto out; } if (!d_deleted(new_dentry) && new_dentry->d_inode) { valid = __unionfs_d_revalidate(new_dentry, new_parent, false); if (!valid) { err = -ESTALE; goto out; } } if (!S_ISDIR(old_dentry->d_inode->i_mode)) err = unionfs_partial_lookup(old_dentry, old_parent); else err = may_rename_dir(old_dentry, old_parent); if (err) goto out; err = unionfs_partial_lookup(new_dentry, new_parent); if (err) goto out; /* * if new_dentry is already lower because of whiteout, * simply override it even if the whited-out dir is not empty. */ wh_dentry = find_first_whiteout(new_dentry); if (!IS_ERR(wh_dentry)) { dput(wh_dentry); } else if (new_dentry->d_inode) { if (S_ISDIR(old_dentry->d_inode->i_mode) != S_ISDIR(new_dentry->d_inode->i_mode)) { err = S_ISDIR(old_dentry->d_inode->i_mode) ? -ENOTDIR : -EISDIR; goto out; } if (S_ISDIR(new_dentry->d_inode->i_mode)) { struct unionfs_dir_state *namelist = NULL; /* check if this unionfs directory is empty or not */ err = check_empty(new_dentry, new_parent, &namelist); if (err) goto out; if (!is_robranch(new_dentry)) err = delete_whiteouts(new_dentry, dbstart(new_dentry), namelist); free_rdstate(namelist); if (err) goto out; } } err = do_unionfs_rename(old_dir, old_dentry, old_parent, new_dir, new_dentry, new_parent); if (err) goto out; /* * force re-lookup since the dir on ro branch is not renamed, and * lower dentries still indicate the un-renamed ones. */ if (S_ISDIR(old_dentry->d_inode->i_mode)) atomic_dec(&UNIONFS_D(old_dentry)->generation); else unionfs_postcopyup_release(old_dentry); if (new_dentry->d_inode && !S_ISDIR(new_dentry->d_inode->i_mode)) { unionfs_postcopyup_release(new_dentry); unionfs_postcopyup_setmnt(new_dentry); if (!unionfs_lower_inode(new_dentry->d_inode)) { /* * If we get here, it means that no copyup was * needed, and that a file by the old name already * existing on the destination branch; that file got * renamed earlier in this function, so all we need * to do here is set the lower inode. */ struct inode *inode; inode = unionfs_lower_inode(old_dentry->d_inode); igrab(inode); unionfs_set_lower_inode_idx(new_dentry->d_inode, dbstart(new_dentry), inode); } } /* if all of this renaming succeeded, update our times */ unionfs_copy_attr_times(old_dentry->d_inode); unionfs_copy_attr_times(new_dentry->d_inode); unionfs_check_inode(old_dir); unionfs_check_inode(new_dir); unionfs_check_dentry(old_dentry); unionfs_check_dentry(new_dentry); out: if (err) /* clear the new_dentry stuff created */ d_drop(new_dentry); unionfs_double_unlock_dentry(old_dentry, new_dentry); if (new_parent != old_dentry && new_parent != new_dentry && new_parent != old_parent) unionfs_unlock_dentry(new_parent); if (old_parent != old_dentry && old_parent != new_dentry) unionfs_unlock_dentry(old_parent); dput(new_parent); dput(old_parent); unionfs_read_unlock(old_dentry->d_sb); return err; }