/* * BKL held by caller. * dentry->d_inode->i_mutex locked */ ssize_t unionfs_listxattr(struct dentry *dentry, char *list, size_t size) { struct dentry *lower_dentry = NULL; struct dentry *parent; int err = -EOPNOTSUPP; char *encoded_list = NULL; bool valid; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); valid = __unionfs_d_revalidate(dentry, parent, false); if (unlikely(!valid)) { err = -ESTALE; goto out; } lower_dentry = unionfs_lower_dentry(dentry); encoded_list = list; err = vfs_listxattr(lower_dentry, encoded_list, size); out: unionfs_check_dentry(dentry); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* * BKL held by caller. * dentry->d_inode->i_mutex locked */ int unionfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct dentry *lower_dentry = NULL; struct dentry *parent; int err = -EOPNOTSUPP; bool valid; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); valid = __unionfs_d_revalidate(dentry, parent, false); if (unlikely(!valid)) { err = -ESTALE; goto out; } lower_dentry = unionfs_lower_dentry(dentry); err = vfs_setxattr(lower_dentry, (char *) name, (void *) value, size, flags); out: unionfs_check_dentry(dentry); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
static int unionfs_rmdir_first(struct inode *dir, struct dentry *dentry, struct unionfs_dir_state *namelist) { int err; struct dentry *hidden_dentry; struct dentry *hidden_dir_dentry = NULL; /* Here we need to remove whiteout entries. */ err = delete_whiteouts(dentry, dbstart(dentry), namelist); if (err) goto out; hidden_dentry = unionfs_lower_dentry(dentry); hidden_dir_dentry = lock_parent(hidden_dentry); /* avoid destroying the hidden inode if the file is in use */ dget(hidden_dentry); if (!(err = is_robranch(dentry))) err = vfs_rmdir(hidden_dir_dentry->d_inode, hidden_dentry); dput(hidden_dentry); fsstack_copy_attr_times(dir, hidden_dir_dentry->d_inode); /* propagate number of hard-links */ dentry->d_inode->i_nlink = unionfs_get_nlinks(dentry->d_inode); out: if (hidden_dir_dentry) unlock_dir(hidden_dir_dentry); return err; }
/* open the highest priority file for a given upper file */ static int open_highest_file(struct file *file, bool willwrite) { int bindex, bstart, bend, err = 0; struct file *lower_file; struct dentry *lower_dentry; struct dentry *dentry = file->f_path.dentry; struct dentry *parent = dget_parent(dentry); struct inode *parent_inode = parent->d_inode; struct super_block *sb = dentry->d_sb; bstart = dbstart(dentry); bend = dbend(dentry); lower_dentry = unionfs_lower_dentry(dentry); if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) { for (bindex = bstart - 1; bindex >= 0; bindex--) { err = copyup_file(parent_inode, file, bstart, bindex, i_size_read(dentry->d_inode)); if (!err) break; } atomic_set(&UNIONFS_F(file)->generation, atomic_read(&UNIONFS_I(dentry->d_inode)-> generation)); goto out; } dget(lower_dentry); unionfs_mntget(dentry, bstart); lower_file = dentry_open(lower_dentry, unionfs_lower_mnt_idx(dentry, bstart), file->f_flags, current_cred()); if (IS_ERR(lower_file)) { err = PTR_ERR(lower_file); goto out; } branchget(sb, bstart); unionfs_set_lower_file(file, lower_file); /* Fix up the position. */ lower_file->f_pos = file->f_pos; memcpy(&lower_file->f_ra, &file->f_ra, sizeof(struct file_ra_state)); out: dput(parent); return err; }
/* requires sb, dentry, and parent to already be locked */ static int __unionfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) { int err; struct dentry *lower_dentry; lower_dentry = unionfs_lower_dentry(dentry); if (!lower_dentry->d_inode->i_op || !lower_dentry->d_inode->i_op->readlink) { err = -EINVAL; goto out; } err = lower_dentry->d_inode->i_op->readlink(lower_dentry, buf, bufsiz); if (err >= 0) fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode); out: return err; }
static int unionfs_setattr(struct dentry *dentry, struct iattr *ia) { int err = 0; struct dentry *lower_dentry; struct dentry *parent; struct inode *inode; struct inode *lower_inode; int bstart, bend, bindex; loff_t size; struct iattr lower_ia; /* check if user has permission to change inode */ err = inode_change_ok(dentry->d_inode, ia); if (err) goto out_err; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); if (unlikely(!__unionfs_d_revalidate(dentry, parent, false, 0))) { err = -ESTALE; goto out; } bstart = dbstart(dentry); bend = dbend(dentry); inode = dentry->d_inode; /* * mode change is for clearing setuid/setgid. Allow lower filesystem * to reinterpret it in its own way. */ if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) ia->ia_valid &= ~ATTR_MODE; lower_dentry = unionfs_lower_dentry(dentry); if (!lower_dentry) { /* should never happen after above revalidate */ err = -EINVAL; goto out; } /* * Get the lower inode directly from lower dentry, in case ibstart * is -1 (which happens when the file is open but unlinked. */ lower_inode = lower_dentry->d_inode; /* check if user has permission to change lower inode */ err = inode_change_ok(lower_inode, ia); if (err) goto out; /* copyup if the file is on a read only branch */ if (is_robranch_super(dentry->d_sb, bstart) || __is_rdonly(lower_inode)) { /* check if we have a branch to copy up to */ if (bstart <= 0) { err = -EACCES; goto out; } if (ia->ia_valid & ATTR_SIZE) size = ia->ia_size; else size = i_size_read(inode); /* copyup to next available branch */ for (bindex = bstart - 1; bindex >= 0; bindex--) { err = copyup_dentry(parent->d_inode, dentry, bstart, bindex, dentry->d_name.name, dentry->d_name.len, NULL, size); if (!err) break; } if (err) goto out; /* get updated lower_dentry/inode after copyup */ lower_dentry = unionfs_lower_dentry(dentry); lower_inode = unionfs_lower_inode(inode); /* * check for whiteouts in writeable branch, and remove them * if necessary. */ if (lower_dentry) { err = check_unlink_whiteout(dentry, lower_dentry, bindex); if (err > 0) /* ignore if whiteout found and removed */ err = 0; } } /* * If shrinking, first truncate upper level to cancel writing dirty * pages beyond the new eof; and also if its' maxbytes is more * limiting (fail with -EFBIG before making any change to the lower * level). There is no need to vmtruncate the upper level * afterwards in the other cases: we fsstack_copy_inode_size from * the lower level. */ if (ia->ia_valid & ATTR_SIZE) { err = inode_newsize_ok(inode, ia->ia_size); if (err) goto out; truncate_setsize(inode, ia->ia_size); } /* notify the (possibly copied-up) lower inode */ /* * Note: we use lower_dentry->d_inode, because lower_inode may be * unlinked (no inode->i_sb and i_ino==0. This happens if someone * tries to open(), unlink(), then ftruncate() a file. */ /* prepare our own lower struct iattr (with our own lower file) */ memcpy(&lower_ia, ia, sizeof(lower_ia)); if (ia->ia_valid & ATTR_FILE) { lower_ia.ia_file = unionfs_lower_file(ia->ia_file); BUG_ON(!lower_ia.ia_file); // XXX? } mutex_lock(&lower_dentry->d_inode->i_mutex); err = notify_change(lower_dentry, &lower_ia); mutex_unlock(&lower_dentry->d_inode->i_mutex); if (err) goto out; /* get attributes from the first lower inode */ if (ibstart(inode) >= 0) unionfs_copy_attr_all(inode, lower_inode); /* * unionfs_copy_attr_all will copy the lower times to our inode if * the lower ones are newer (useful for cache coherency). However, * ->setattr is the only place in which we may have to copy the * lower inode times absolutely, to support utimes(2). */ if (ia->ia_valid & ATTR_MTIME_SET) inode->i_mtime = lower_inode->i_mtime; if (ia->ia_valid & ATTR_CTIME) inode->i_ctime = lower_inode->i_ctime; if (ia->ia_valid & ATTR_ATIME_SET) inode->i_atime = lower_inode->i_atime; fsstack_copy_inode_size(inode, lower_inode); out: if (!err) unionfs_check_dentry(dentry); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); out_err: return err; }
static int unionfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int err = 0; struct dentry *lower_dentry = NULL; struct dentry *lower_parent_dentry = NULL; struct dentry *parent; int bindex = 0, bstart; char *name = NULL; int valid; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); valid = __unionfs_d_revalidate(dentry, parent, false, 0); if (unlikely(!valid)) { err = -ESTALE; /* same as what real_lookup does */ goto out; } bstart = dbstart(dentry); lower_dentry = unionfs_lower_dentry(dentry); /* check for a whiteout in new dentry branch, and delete it */ err = check_unlink_whiteout(dentry, lower_dentry, bstart); if (err > 0) /* whiteout found and removed successfully */ err = 0; if (err) { /* exit if the error returned was NOT -EROFS */ if (!IS_COPYUP_ERR(err)) goto out; bstart--; } /* check if copyup's needed, and mkdir */ for (bindex = bstart; bindex >= 0; bindex--) { int i; int bend = dbend(dentry); if (is_robranch_super(dentry->d_sb, bindex)) continue; lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); if (!lower_dentry) { lower_dentry = create_parents(dir, dentry, dentry->d_name.name, bindex); if (!lower_dentry || IS_ERR(lower_dentry)) { printk(KERN_ERR "unionfs: lower dentry " " NULL for bindex = %d\n", bindex); continue; } } lower_parent_dentry = lock_parent(lower_dentry); if (IS_ERR(lower_parent_dentry)) { err = PTR_ERR(lower_parent_dentry); goto out; } err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry, mode); unlock_dir(lower_parent_dentry); /* did the mkdir succeed? */ if (err) break; for (i = bindex + 1; i <= bend; i++) { /* XXX: use path_put_lowers? */ if (unionfs_lower_dentry_idx(dentry, i)) { dput(unionfs_lower_dentry_idx(dentry, i)); unionfs_set_lower_dentry_idx(dentry, i, NULL); } } dbend(dentry) = bindex; /* * Only INTERPOSE_LOOKUP can return a value other than 0 on * err. */ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0)); if (!err) { unionfs_copy_attr_times(dir); fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode); /* update number of links on parent directory */ set_nlink(dir, unionfs_get_nlinks(dir)); } err = make_dir_opaque(dentry, dbstart(dentry)); if (err) { printk(KERN_ERR "unionfs: mkdir: error creating " ".wh.__dir_opaque: %d\n", err); goto out; } /* we are done! */ break; } out: if (!dentry->d_inode) d_drop(dentry); kfree(name); if (!err) { unionfs_copy_attr_times(dentry->d_inode); unionfs_postcopyup_setmnt(dentry); } unionfs_check_inode(dir); unionfs_check_dentry(dentry); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
static int unionfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) { int err = 0; struct dentry *lower_old_dentry = NULL; struct dentry *lower_new_dentry = NULL; struct dentry *lower_dir_dentry = NULL; struct dentry *old_parent, *new_parent; char *name = NULL; bool valid; unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD); old_parent = dget_parent(old_dentry); new_parent = dget_parent(new_dentry); unionfs_double_lock_parents(old_parent, new_parent); unionfs_double_lock_dentry(old_dentry, new_dentry); valid = __unionfs_d_revalidate(old_dentry, old_parent, false, 0); if (unlikely(!valid)) { err = -ESTALE; goto out; } if (new_dentry->d_inode) { valid = __unionfs_d_revalidate(new_dentry, new_parent, false, 0); if (unlikely(!valid)) { err = -ESTALE; goto out; } } lower_new_dentry = unionfs_lower_dentry(new_dentry); /* check for a whiteout in new dentry branch, and delete it */ err = check_unlink_whiteout(new_dentry, lower_new_dentry, dbstart(new_dentry)); if (err > 0) { /* whiteout found and removed successfully */ lower_dir_dentry = dget_parent(lower_new_dentry); fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); dput(lower_dir_dentry); set_nlink(dir, unionfs_get_nlinks(dir)); err = 0; } if (err) goto out; /* check if parent hierachy is needed, then link in same branch */ if (dbstart(old_dentry) != dbstart(new_dentry)) { lower_new_dentry = create_parents(dir, new_dentry, new_dentry->d_name.name, dbstart(old_dentry)); err = PTR_ERR(lower_new_dentry); if (IS_COPYUP_ERR(err)) goto docopyup; if (!lower_new_dentry || IS_ERR(lower_new_dentry)) goto out; } lower_new_dentry = unionfs_lower_dentry(new_dentry); lower_old_dentry = unionfs_lower_dentry(old_dentry); BUG_ON(dbstart(old_dentry) != dbstart(new_dentry)); lower_dir_dentry = lock_parent(lower_new_dentry); err = is_robranch(old_dentry); if (!err) { /* see Documentation/filesystems/unionfs/issues.txt */ lockdep_off(); err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, lower_new_dentry); lockdep_on(); } unlock_dir(lower_dir_dentry); docopyup: if (IS_COPYUP_ERR(err)) { int old_bstart = dbstart(old_dentry); int bindex; for (bindex = old_bstart - 1; bindex >= 0; bindex--) { err = copyup_dentry(old_parent->d_inode, old_dentry, old_bstart, bindex, old_dentry->d_name.name, old_dentry->d_name.len, NULL, i_size_read(old_dentry->d_inode)); if (err) continue; lower_new_dentry = create_parents(dir, new_dentry, new_dentry->d_name.name, bindex); lower_old_dentry = unionfs_lower_dentry(old_dentry); lower_dir_dentry = lock_parent(lower_new_dentry); /* see Documentation/filesystems/unionfs/issues.txt */ lockdep_off(); /* do vfs_link */ err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, lower_new_dentry); lockdep_on(); unlock_dir(lower_dir_dentry); goto check_link; } goto out; } check_link: if (err || !lower_new_dentry->d_inode) goto out; /* Its a hard link, so use the same inode */ new_dentry->d_inode = igrab(old_dentry->d_inode); d_add(new_dentry, new_dentry->d_inode); unionfs_copy_attr_all(dir, lower_new_dentry->d_parent->d_inode); fsstack_copy_inode_size(dir, lower_new_dentry->d_parent->d_inode); /* propagate number of hard-links */ set_nlink(old_dentry->d_inode, unionfs_get_nlinks(old_dentry->d_inode)); /* new dentry's ctime may have changed due to hard-link counts */ unionfs_copy_attr_times(new_dentry->d_inode); out: if (!new_dentry->d_inode) d_drop(new_dentry); kfree(name); if (!err) unionfs_postcopyup_setmnt(new_dentry); unionfs_check_inode(dir); unionfs_check_dentry(new_dentry); unionfs_check_dentry(old_dentry); unionfs_double_unlock_dentry(old_dentry, new_dentry); unionfs_double_unlock_parents(old_parent, new_parent); dput(new_parent); dput(old_parent); unionfs_read_unlock(old_dentry->d_sb); return err; }
/* * 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; }
struct dentry *unionfs_lookup_backend(struct dentry *dentry, struct nameidata *nd, int lookupmode) { int err = 0; struct dentry *hidden_dentry = NULL; struct dentry *wh_hidden_dentry = NULL; struct dentry *hidden_dir_dentry = NULL; struct dentry *parent_dentry = NULL; int bindex, bstart, bend, bopaque; int dentry_count = 0; /* Number of positive dentries. */ int first_dentry_offset = -1; struct dentry *first_hidden_dentry = NULL; struct vfsmount *first_hidden_mnt = NULL; int locked_parent = 0; int locked_child = 0; int opaque; char *whname = NULL; const char *name; int namelen; /* We should already have a lock on this dentry in the case of a * partial lookup, or a revalidation. Otherwise it is returned from * new_dentry_private_data already locked. */ if (lookupmode == INTERPOSE_PARTIAL || lookupmode == INTERPOSE_REVAL || lookupmode == INTERPOSE_REVAL_NEG) verify_locked(dentry); else { BUG_ON(UNIONFS_D(dentry) != NULL); locked_child = 1; } if (lookupmode != INTERPOSE_PARTIAL) if ((err = new_dentry_private_data(dentry))) goto out; /* must initialize dentry operations */ dentry->d_op = &unionfs_dops; parent_dentry = dget_parent(dentry); /* We never partial lookup the root directory. */ if (parent_dentry != dentry) { unionfs_lock_dentry(parent_dentry); locked_parent = 1; } else { dput(parent_dentry); parent_dentry = NULL; goto out; } name = dentry->d_name.name; namelen = dentry->d_name.len; /* No dentries should get created for possible whiteout names. */ if (!is_validname(name)) { err = -EPERM; goto out_free; } /* Now start the actual lookup procedure. */ bstart = dbstart(parent_dentry); bend = dbend(parent_dentry); bopaque = dbopaque(parent_dentry); BUG_ON(bstart < 0); /* It would be ideal if we could convert partial lookups to only have * to do this work when they really need to. It could probably improve * performance quite a bit, and maybe simplify the rest of the code. */ if (lookupmode == INTERPOSE_PARTIAL) { bstart++; if ((bopaque != -1) && (bopaque < bend)) bend = bopaque; } for (bindex = bstart; bindex <= bend; bindex++) { hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); if (lookupmode == INTERPOSE_PARTIAL && hidden_dentry) continue; BUG_ON(hidden_dentry != NULL); hidden_dir_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex); /* if the parent hidden dentry does not exist skip this */ if (!(hidden_dir_dentry && hidden_dir_dentry->d_inode)) continue; /* also skip it if the parent isn't a directory. */ if (!S_ISDIR(hidden_dir_dentry->d_inode->i_mode)) continue; /* Reuse the whiteout name because its value doesn't change. */ if (!whname) { whname = alloc_whname(name, namelen); if (IS_ERR(whname)) { err = PTR_ERR(whname); goto out_free; } } /* check if whiteout exists in this branch: lookup .wh.foo */ wh_hidden_dentry = lookup_one_len(whname, hidden_dir_dentry, namelen + UNIONFS_WHLEN); if (IS_ERR(wh_hidden_dentry)) { dput(first_hidden_dentry); mntput(first_hidden_mnt); err = PTR_ERR(wh_hidden_dentry); goto out_free; } if (wh_hidden_dentry->d_inode) { /* We found a whiteout so lets give up. */ if (S_ISREG(wh_hidden_dentry->d_inode->i_mode)) { set_dbend(dentry, bindex); set_dbopaque(dentry, bindex); dput(wh_hidden_dentry); break; } err = -EIO; printk(KERN_NOTICE "EIO: Invalid whiteout entry type" " %d.\n", wh_hidden_dentry->d_inode->i_mode); dput(wh_hidden_dentry); dput(first_hidden_dentry); mntput(first_hidden_mnt); goto out_free; } dput(wh_hidden_dentry); wh_hidden_dentry = NULL; /* Now do regular lookup; lookup foo */ nd->dentry = unionfs_lower_dentry_idx(dentry, bindex); /* FIXME: fix following line for mount point crossing */ nd->mnt = unionfs_lower_mnt_idx(parent_dentry, bindex); hidden_dentry = lookup_one_len_nd(name, hidden_dir_dentry, namelen, nd); if (IS_ERR(hidden_dentry)) { dput(first_hidden_dentry); mntput(first_hidden_mnt); err = PTR_ERR(hidden_dentry); goto out_free; } /* Store the first negative dentry specially, because if they * are all negative we need this for future creates. */ if (!hidden_dentry->d_inode) { if (!first_hidden_dentry && (dbstart(dentry) == -1)) { first_hidden_dentry = hidden_dentry; /* FIXME: following line needs to be changed * to allow mountpoint crossing */ first_hidden_mnt = mntget( unionfs_lower_mnt_idx(parent_dentry, bindex)); first_dentry_offset = bindex; } else dput(hidden_dentry); continue; } /* number of positive dentries */ dentry_count++; /* store underlying dentry */ if (dbstart(dentry) == -1) set_dbstart(dentry, bindex); unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry); /* FIXME: the following line needs to get fixed to allow * mountpoint crossing */ unionfs_set_lower_mnt_idx(dentry, bindex, mntget(unionfs_lower_mnt_idx(parent_dentry, bindex))); set_dbend(dentry, bindex); /* update parent directory's atime with the bindex */ fsstack_copy_attr_atime(parent_dentry->d_inode, hidden_dir_dentry->d_inode); /* We terminate file lookups here. */ if (!S_ISDIR(hidden_dentry->d_inode->i_mode)) { if (lookupmode == INTERPOSE_PARTIAL) continue; if (dentry_count == 1) goto out_positive; /* This can only happen with mixed D-*-F-* */ BUG_ON(!S_ISDIR(unionfs_lower_dentry(dentry)->d_inode->i_mode)); continue; } opaque = is_opaque_dir(dentry, bindex); if (opaque < 0) { dput(first_hidden_dentry); mntput(first_hidden_mnt); err = opaque; goto out_free; } else if (opaque) { set_dbend(dentry, bindex); set_dbopaque(dentry, bindex); break; } } if (dentry_count) goto out_positive; else goto out_negative; out_negative: if (lookupmode == INTERPOSE_PARTIAL) goto out; /* If we've only got negative dentries, then use the leftmost one. */ if (lookupmode == INTERPOSE_REVAL) { if (dentry->d_inode) UNIONFS_I(dentry->d_inode)->stale = 1; goto out; } /* This should only happen if we found a whiteout. */ if (first_dentry_offset == -1) { nd->dentry = dentry; /* FIXME: fix following line for mount point crossing */ nd->mnt = unionfs_lower_mnt_idx(parent_dentry, bindex); first_hidden_dentry = lookup_one_len_nd(name, hidden_dir_dentry, namelen, nd); first_dentry_offset = bindex; if (IS_ERR(first_hidden_dentry)) { err = PTR_ERR(first_hidden_dentry); goto out; } /* FIXME: the following line needs to be changed to allow * mountpoint crossing */ first_hidden_mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex)); } unionfs_set_lower_dentry_idx(dentry, first_dentry_offset, first_hidden_dentry); unionfs_set_lower_mnt_idx(dentry, first_dentry_offset, first_hidden_mnt); set_dbstart(dentry, first_dentry_offset); set_dbend(dentry, first_dentry_offset); if (lookupmode == INTERPOSE_REVAL_NEG) BUG_ON(dentry->d_inode != NULL); else d_add(dentry, NULL); goto out; /* This part of the code is for positive dentries. */ out_positive: BUG_ON(dentry_count <= 0); /* If we're holding onto the first negative dentry & corresponding * vfsmount - throw it out. */ dput(first_hidden_dentry); mntput(first_hidden_mnt); /* Partial lookups need to reinterpose, or throw away older negs. */ if (lookupmode == INTERPOSE_PARTIAL) { if (dentry->d_inode) { unionfs_reinterpose(dentry); goto out; } /* This somehow turned positive, so it is as if we had a * negative revalidation. */ lookupmode = INTERPOSE_REVAL_NEG; update_bstart(dentry); bstart = dbstart(dentry); bend = dbend(dentry); } err = unionfs_interpose(dentry, dentry->d_sb, lookupmode); if (err) goto out_drop; goto out; out_drop: d_drop(dentry); out_free: /* should dput all the underlying dentries on error condition */ bstart = dbstart(dentry); if (bstart >= 0) { bend = dbend(dentry); for (bindex = bstart; bindex <= bend; bindex++) { dput(unionfs_lower_dentry_idx(dentry, bindex)); mntput(unionfs_lower_mnt_idx(dentry, bindex)); } } kfree(UNIONFS_D(dentry)->lower_paths); UNIONFS_D(dentry)->lower_paths = NULL; set_dbstart(dentry, -1); set_dbend(dentry, -1); out: if (!err && UNIONFS_D(dentry)) { BUG_ON(dbend(dentry) > UNIONFS_D(dentry)->bcount); BUG_ON(dbend(dentry) > sbmax(dentry->d_sb)); BUG_ON(dbstart(dentry) < 0); } kfree(whname); if (locked_parent) unionfs_unlock_dentry(parent_dentry); dput(parent_dentry); if (locked_child) unionfs_unlock_dentry(dentry); return ERR_PTR(err); }
/* unionfs_open helper function: open a file */ static int __open_file(struct inode *inode, struct file *file, struct dentry *parent) { struct dentry *lower_dentry; struct file *lower_file; int lower_flags; int bindex, bstart, bend; lower_dentry = unionfs_lower_dentry(file->f_path.dentry); lower_flags = file->f_flags; bstart = fbstart(file) = dbstart(file->f_path.dentry); bend = fbend(file) = dbend(file->f_path.dentry); /* * check for the permission for lower file. If the error is * COPYUP_ERR, copyup the file. */ if (lower_dentry->d_inode && is_robranch(file->f_path.dentry)) { /* * if the open will change the file, copy it up otherwise * defer it. */ if (lower_flags & O_TRUNC) { int size = 0; int err = -EROFS; /* copyup the file */ for (bindex = bstart - 1; bindex >= 0; bindex--) { err = copyup_file(parent->d_inode, file, bstart, bindex, size); if (!err) { /* only one regular file open */ fbend(file) = fbstart(file); break; } } return err; } else { /* * turn off writeable flags, to force delayed copyup * by caller. */ lower_flags &= ~(OPEN_WRITE_FLAGS); } } dget(lower_dentry); /* * dentry_open will decrement mnt refcnt if err. * otherwise fput() will do an mntput() for us upon file close. */ unionfs_mntget(file->f_path.dentry, bstart); lower_file = dentry_open(lower_dentry, unionfs_lower_mnt_idx(file->f_path.dentry, bstart), lower_flags, current_cred()); if (IS_ERR(lower_file)) return PTR_ERR(lower_file); unionfs_set_lower_file(file, lower_file); branchget(inode->i_sb, bstart); return 0; }