static ssize_t unionfs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos, size_t len, unsigned int flags) { ssize_t err = 0; struct file *lower_file; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, true); if (unlikely(err)) goto out; lower_file = unionfs_lower_file(file); err = vfs_splice_from(pipe, lower_file, ppos, len, flags); /* update our inode times+sizes upon a successful lower write */ if (err >= 0) { fsstack_copy_inode_size(dentry->d_inode, lower_file->f_path.dentry->d_inode); fsstack_copy_attr_times(dentry->d_inode, lower_file->f_path.dentry->d_inode); unionfs_check_file(file); } out: unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
static ssize_t unionfs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { int err = 0; struct file *lower_file; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, true); if (unlikely(err)) goto out; lower_file = unionfs_lower_file(file); err = vfs_write(lower_file, buf, count, ppos); /* update our inode times+sizes upon a successful lower write */ if (err >= 0) { fsstack_copy_inode_size(dentry->d_inode, lower_file->f_path.dentry->d_inode); fsstack_copy_attr_times(dentry->d_inode, lower_file->f_path.dentry->d_inode); UNIONFS_F(file)->wrote_to_file = true; /* for delayed copyup */ unionfs_check_file(file); } out: unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
static ssize_t unionfs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { int err; struct file *lower_file; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, false); if (unlikely(err)) goto out; lower_file = unionfs_lower_file(file); err = vfs_read(lower_file, buf, count, ppos); /* update our inode atime upon a successful lower read */ if (err >= 0) { fsstack_copy_attr_atime(dentry->d_inode, lower_file->f_path.dentry->d_inode); unionfs_check_file(file); } out: 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 */ 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; }
/* this @nd *IS* still used */ static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) { struct dentry *parent; char *buf; 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))) printk(KERN_ERR "unionfs: put_link failed to revalidate dentry\n"); unionfs_check_dentry(dentry); #if 0 /* XXX: can't run this check b/c this fxn can receive a poisoned 'nd' PTR */ unionfs_check_nd(nd); #endif buf = nd_get_link(nd); if (!IS_ERR(buf)) kfree(buf); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); }
static int unionfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) { int err; struct dentry *parent; 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; } err = __unionfs_readlink(dentry, buf, bufsiz); 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_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool want_excl) { int err = 0; struct dentry *lower_dentry = NULL; struct dentry *lower_parent_dentry = NULL; struct dentry *parent; int valid = 0; 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; } lower_dentry = find_writeable_branch(dir, dentry); if (IS_ERR(lower_dentry)) { err = PTR_ERR(lower_dentry); goto out; } lower_parent_dentry = lock_parent(lower_dentry); if (IS_ERR(lower_parent_dentry)) { err = PTR_ERR(lower_parent_dentry); goto out_unlock; } err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode, want_excl); if (!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 no. of links on parent directory */ set_nlink(dir, unionfs_get_nlinks(dir)); } } out_unlock: unlock_dir(lower_parent_dentry); out: if (!err) { 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; }
int unionfs_fsync(struct file *file, struct dentry *dentry, int datasync) { int bindex, bstart, bend; struct file *lower_file; struct dentry *lower_dentry; struct dentry *parent; struct inode *lower_inode, *inode; int err = -EINVAL; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, true); if (unlikely(err)) goto out; unionfs_check_file(file); bstart = fbstart(file); bend = fbend(file); if (bstart < 0 || bend < 0) goto out; inode = dentry->d_inode; if (unlikely(!inode)) { printk(KERN_ERR "unionfs: null lower inode in unionfs_fsync\n"); goto out; } for (bindex = bstart; bindex <= bend; bindex++) { lower_inode = unionfs_lower_inode_idx(inode, bindex); if (!lower_inode || !lower_inode->i_fop->fsync) continue; lower_file = unionfs_lower_file_idx(file, bindex); lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); mutex_lock(&lower_inode->i_mutex); err = lower_inode->i_fop->fsync(lower_file, lower_dentry, datasync); if (!err && bindex == bstart) fsstack_copy_attr_times(inode, lower_inode); mutex_unlock(&lower_inode->i_mutex); if (err) goto out; } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* * 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; }
static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd) { char *buf; int len = PAGE_SIZE, err; mm_segment_t old_fs; struct dentry *parent; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* This is freed by the put_link method assuming a successful call. */ buf = kmalloc(len, GFP_KERNEL); if (unlikely(!buf)) { err = -ENOMEM; goto out; } /* read the symlink, and then we will follow it */ old_fs = get_fs(); set_fs(KERNEL_DS); err = __unionfs_readlink(dentry, buf, len); set_fs(old_fs); if (err < 0) { kfree(buf); buf = NULL; goto out; } buf[err] = 0; nd_set_link(nd, buf); err = 0; out: if (err >= 0) { unionfs_check_nd(nd); unionfs_check_dentry(dentry); } unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return ERR_PTR(err); }
/* this @nd *IS* still used */ static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) { struct dentry *parent; 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))) printk(KERN_ERR "unionfs: put_link failed to revalidate dentry\n"); unionfs_check_dentry(dentry); unionfs_check_nd(nd); kfree(nd_get_link(nd)); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); }
long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { long err; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, true); if (unlikely(err)) goto out; /* check if asked for local commands */ switch (cmd) { case UNIONFS_IOCTL_INCGEN: /* Increment the superblock generation count */ pr_info("unionfs: incgen ioctl deprecated; " "use \"-o remount,incgen\"\n"); err = -ENOSYS; break; case UNIONFS_IOCTL_QUERYFILE: /* Return list of branches containing the given file */ err = unionfs_ioctl_queryfile(file, parent, cmd, arg); break; default: /* pass the ioctl down */ err = do_ioctl(file, cmd, arg); break; } out: unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
int unionfs_flush(struct file *file, fl_owner_t id) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex, bstart, bend; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, UNIONFS_F(file)->wrote_to_file); if (unlikely(err)) goto out; unionfs_check_file(file); bstart = fbstart(file); bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (lower_file && lower_file->f_op && lower_file->f_op->flush) { err = lower_file->f_op->flush(lower_file, id); if (err) goto out; } } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* copy up a dentry to a file of specified name */ static int copyup_named_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_hidden_dentry; struct dentry *old_hidden_dentry = NULL; struct super_block *sb; int err = 0; int old_bindex; int old_bstart; int old_bend; struct dentry *new_hidden_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; unionfs_read_lock(sb); if ((err = is_robranch_super(sb, new_bindex))) { dput(old_hidden_dentry); goto out; } /* Create the directory structure above this dentry. */ new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex); if (IS_ERR(new_hidden_dentry)) { dput(old_hidden_dentry); err = PTR_ERR(new_hidden_dentry); goto out; } old_hidden_dentry = unionfs_lower_dentry_idx(dentry, old_bindex); dget(old_hidden_dentry); /* For symlinks, we must read the link before we lock the directory. */ if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) { symbuf = kmalloc(PATH_MAX, GFP_KERNEL); if (!symbuf) { __clear(dentry, old_hidden_dentry, old_bstart, old_bend, new_hidden_dentry, new_bindex); err = -ENOMEM; goto out_free; } oldfs = get_fs(); set_fs(KERNEL_DS); err = old_hidden_dentry->d_inode->i_op->readlink( old_hidden_dentry, (char __user *)symbuf, PATH_MAX); set_fs(oldfs); if (err) { __clear(dentry, old_hidden_dentry, old_bstart, old_bend, new_hidden_dentry, new_bindex); goto out_free; } symbuf[err] = '\0'; } /* Now we lock the parent, and create the object in the new branch. */ new_hidden_parent_dentry = lock_parent(new_hidden_dentry); /* create the new inode */ err = __copyup_ndentry(old_hidden_dentry, new_hidden_dentry, new_hidden_parent_dentry, symbuf); if (err) { __clear(dentry, old_hidden_dentry, old_bstart, old_bend, new_hidden_dentry, new_bindex); goto out_unlock; } /* We actually copyup the file here. */ if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) err = __copyup_reg_data(dentry, new_hidden_dentry, new_bindex, old_hidden_dentry, old_bindex, copyup_file, len); if (err) goto out_unlink; /* Set permissions. */ if ((err = copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry))) goto out_unlink; #ifdef CONFIG_UNION_FS_XATTR /* Selinux uses extended attributes for permissions. */ if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry))) goto out_unlink; #endif /* do not allow files getting deleted to be reinterposed */ 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_hidden_parent_dentry->d_inode, new_hidden_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 non-sensical 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_hidden_parent_dentry); out_free: kfree(symbuf); out: unionfs_read_unlock(sb); return err; }
static int unionfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { int err = 0; struct dentry *lower_dentry = NULL; struct dentry *wh_dentry = NULL; struct dentry *lower_parent_dentry = NULL; struct dentry *parent; char *name = NULL; int valid = 0; 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; goto out; } /* * It's only a bug if this dentry was not negative and couldn't be * revalidated (shouldn't happen). */ BUG_ON(!valid && dentry->d_inode); lower_dentry = find_writeable_branch(dir, dentry); if (IS_ERR(lower_dentry)) { err = PTR_ERR(lower_dentry); goto out; } lower_parent_dentry = lock_parent(lower_dentry); if (IS_ERR(lower_parent_dentry)) { err = PTR_ERR(lower_parent_dentry); goto out_unlock; } err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev); if (!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 no. of links on parent directory */ set_nlink(dir, unionfs_get_nlinks(dir)); } } out_unlock: unlock_dir(lower_parent_dentry); out: dput(wh_dentry); kfree(name); if (!err) { 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_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; }
/* * 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; }
static int unionfs_mmap(struct file *file, struct vm_area_struct *vma) { int err = 0; bool willwrite; struct file *lower_file; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; struct vm_operations_struct *saved_vm_ops = NULL; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* This might be deferred to mmap's writepage */ willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags); err = unionfs_file_revalidate(file, parent, willwrite); if (unlikely(err)) goto out; unionfs_check_file(file); /* * File systems which do not implement ->writepage may use * generic_file_readonly_mmap as their ->mmap op. If you call * generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL. * But we cannot call the lower ->mmap op, so we can't tell that * writeable mappings won't work. Therefore, our only choice is to * check if the lower file system supports the ->writepage, and if * not, return EINVAL (the same error that * generic_file_readonly_mmap returns in that case). */ lower_file = unionfs_lower_file(file); if (willwrite && !lower_file->f_mapping->a_ops->writepage) { err = -EINVAL; printk(KERN_ERR "unionfs: branch %d file system does not " "support writeable mmap\n", fbstart(file)); goto out; } /* * find and save lower vm_ops. * * XXX: the VFS should have a cleaner way of finding the lower vm_ops */ if (!UNIONFS_F(file)->lower_vm_ops) { err = lower_file->f_op->mmap(lower_file, vma); if (err) { printk(KERN_ERR "unionfs: lower mmap failed %d\n", err); goto out; } saved_vm_ops = vma->vm_ops; err = do_munmap(current->mm, vma->vm_start, vma->vm_end - vma->vm_start); if (err) { printk(KERN_ERR "unionfs: do_munmap failed %d\n", err); goto out; } } file->f_mapping->a_ops = &unionfs_dummy_aops; err = generic_file_mmap(file, vma); file->f_mapping->a_ops = &unionfs_aops; if (err) { printk(KERN_ERR "unionfs: generic_file_mmap failed %d\n", err); goto out; } vma->vm_ops = &unionfs_vm_ops; if (!UNIONFS_F(file)->lower_vm_ops) UNIONFS_F(file)->lower_vm_ops = saved_vm_ops; out: if (!err) { /* copyup could cause parent dir times to change */ unionfs_copy_attr_times(parent->d_inode); unionfs_check_file(file); } unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* * This is not meant to be a generic repositioning function. If you do * things that aren't supported, then we return EINVAL. * * What is allowed: * (1) seeking to the same position that you are currently at * This really has no effect, but returns where you are. * (2) seeking to the beginning of the file * This throws out all state, and lets you begin again. */ static loff_t unionfs_dir_llseek(struct file *file, loff_t offset, int origin) { struct unionfs_dir_state *rdstate; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; loff_t err; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, false); if (unlikely(err)) goto out; rdstate = UNIONFS_F(file)->rdstate; /* * we let users seek to their current position, but not anywhere * else. */ if (!offset) { switch (origin) { case SEEK_SET: if (rdstate) { free_rdstate(rdstate); UNIONFS_F(file)->rdstate = NULL; } init_rdstate(file); err = 0; break; case SEEK_CUR: err = file->f_pos; break; case SEEK_END: /* Unsupported, because we would break everything. */ err = -EINVAL; break; } } else { switch (origin) { case SEEK_SET: if (rdstate) { if (offset == rdstate2offset(rdstate)) err = offset; else if (file->f_pos == DIREOF) err = DIREOF; else err = -EINVAL; } else { struct inode *inode; inode = dentry->d_inode; rdstate = find_rdstate(inode, offset); if (rdstate) { UNIONFS_F(file)->rdstate = rdstate; err = rdstate->offset; } else { err = -EINVAL; } } break; case SEEK_CUR: case SEEK_END: /* Unsupported, because we would break everything. */ err = -EINVAL; break; } } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); 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; }
/* * release all lower object references & free the file info structure * * No need to grab sb info's rwsem. */ int unionfs_file_release(struct inode *inode, struct file *file) { struct file *lower_file = NULL; struct unionfs_file_info *fileinfo; struct unionfs_inode_info *inodeinfo; struct super_block *sb = inode->i_sb; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex, bstart, bend; int fgen, err = 0; /* * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this * has been causing false positives in file system stacking layers. * In particular, our ->mmap is called after sys_mmap2 already holds * mmap_sem, then we lock our own mutexes; but earlier, it's * possible for lockdep to have locked our mutexes first, and then * we call a lower ->readdir which could call might_fault. The * different ordering of the locks is what lockdep complains about * -- unnecessarily. Therefore, we have no choice but to tell * lockdep to temporarily turn off lockdep here. Note: the comments * inside might_sleep also suggest that it would have been * nicer to only annotate paths that needs that might_lock_read. */ lockdep_off(); unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* * We try to revalidate, but the VFS ignores return return values * from file->release, so we must always try to succeed here, * including to do the kfree and dput below. So if revalidation * failed, all we can do is print some message and keep going. */ err = unionfs_file_revalidate(file, parent, UNIONFS_F(file)->wrote_to_file); if (!err) unionfs_check_file(file); fileinfo = UNIONFS_F(file); BUG_ON(file->f_path.dentry->d_inode != inode); inodeinfo = UNIONFS_I(inode); /* fput all the lower files */ fgen = atomic_read(&fileinfo->generation); bstart = fbstart(file); bend = fbend(file); for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (lower_file) { unionfs_set_lower_file_idx(file, bindex, NULL); fput(lower_file); branchput(sb, bindex); } /* if there are no more refs to the dentry, dput it */ if (d_deleted(dentry)) { dput(unionfs_lower_dentry_idx(dentry, bindex)); unionfs_set_lower_dentry_idx(dentry, bindex, NULL); } } kfree(fileinfo->lower_files); kfree(fileinfo->saved_branch_ids); if (fileinfo->rdstate) { fileinfo->rdstate->access = jiffies; spin_lock(&inodeinfo->rdlock); inodeinfo->rdcount++; list_add_tail(&fileinfo->rdstate->cache, &inodeinfo->readdircache); mark_inode_dirty(inode); spin_unlock(&inodeinfo->rdlock); fileinfo->rdstate = NULL; } kfree(fileinfo); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(sb); lockdep_on(); return err; }
int unionfs_open(struct inode *inode, struct file *file) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; int bindex = 0, bstart = 0, bend = 0; int size; int valid = 0; unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); /* don't open unhashed/deleted files */ if (d_deleted(dentry)) { err = -ENOENT; goto out_nofree; } /* XXX: should I change 'false' below to the 'willwrite' flag? */ valid = __unionfs_d_revalidate(dentry, parent, false); if (unlikely(!valid)) { err = -ESTALE; goto out_nofree; } file->private_data = kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL); if (unlikely(!UNIONFS_F(file))) { err = -ENOMEM; goto out_nofree; } fbstart(file) = -1; fbend(file) = -1; atomic_set(&UNIONFS_F(file)->generation, atomic_read(&UNIONFS_I(inode)->generation)); size = sizeof(struct file *) * sbmax(inode->i_sb); UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL); if (unlikely(!UNIONFS_F(file)->lower_files)) { err = -ENOMEM; goto out; } size = sizeof(int) * sbmax(inode->i_sb); UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL); if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) { err = -ENOMEM; goto out; } bstart = fbstart(file) = dbstart(dentry); bend = fbend(file) = dbend(dentry); /* * open all directories and make the unionfs file struct point to * these lower file structs */ if (S_ISDIR(inode->i_mode)) err = __open_dir(inode, file); /* open a dir */ else err = __open_file(inode, file, parent); /* open a file */ /* freeing the allocated resources, and fput the opened files */ if (err) { for (bindex = bstart; bindex <= bend; bindex++) { lower_file = unionfs_lower_file_idx(file, bindex); if (!lower_file) continue; branchput(dentry->d_sb, bindex); /* fput calls dput for lower_dentry */ fput(lower_file); } } out: if (err) { kfree(UNIONFS_F(file)->lower_files); kfree(UNIONFS_F(file)->saved_branch_ids); kfree(UNIONFS_F(file)); } out_nofree: if (!err) { unionfs_postcopyup_setmnt(dentry); unionfs_copy_attr_times(inode); unionfs_check_file(file); unionfs_check_inode(inode); } unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(inode->i_sb); return err; }
/* * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise. */ int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd) { int valid = 1; /* default is valid (1); invalid is 0. */ struct dentry *hidden_dentry; int bindex, bstart, bend; int sbgen, dgen; int positive = 0; int locked = 0; int restart = 0; int interpose_flag; print_util_entry_location(); restart: verify_locked(dentry); /* if the dentry is unhashed, do NOT revalidate */ if (d_deleted(dentry)) { fist_dprint(6, "unhashed dentry being revalidated: %*s\n", dentry->d_name.len, dentry->d_name.name); goto out; } BUG_ON(dbstart(dentry) == -1); if (dentry->d_inode) positive = 1; dgen = atomic_read(&dtopd(dentry)->udi_generation); sbgen = atomic_read(&stopd(dentry->d_sb)->usi_generation); /* If we are working on an unconnected dentry, then there is no * revalidation to be done, because this file does not exist within the * namespace, and Unionfs operates on the namespace, not data. */ if (sbgen != dgen) { struct dentry *result; int pdgen; unionfs_read_lock(dentry->d_sb); locked = 1; /* The root entry should always be valid */ BUG_ON(IS_ROOT(dentry)); /* We can't work correctly if our parent isn't valid. */ pdgen = atomic_read(&dtopd(dentry->d_parent)->udi_generation); if (!restart && (pdgen != sbgen)) { unionfs_read_unlock(dentry->d_sb); locked = 0; /* We must be locked before our parent. */ if (! (dentry->d_parent->d_op-> d_revalidate(dentry->d_parent, nd))) { valid = 0; goto out; } restart = 1; goto restart; } BUG_ON(pdgen != sbgen); /* Free the pointers for our inodes and this dentry. */ bstart = dbstart(dentry); bend = dbend(dentry); if (bstart >= 0) { struct dentry *hidden_dentry; for (bindex = bstart; bindex <= bend; bindex++) { hidden_dentry = dtohd_index_nocheck(dentry, bindex); if (!hidden_dentry) continue; DPUT(hidden_dentry); } } set_dbstart(dentry, -1); set_dbend(dentry, -1); interpose_flag = INTERPOSE_REVAL_NEG; if (positive) { interpose_flag = INTERPOSE_REVAL; down(&dentry->d_inode->i_sem); bstart = ibstart(dentry->d_inode); bend = ibend(dentry->d_inode); if (bstart >= 0) { struct inode *hidden_inode; for (bindex = bstart; bindex <= bend; bindex++) { hidden_inode = itohi_index(dentry->d_inode, bindex); if (!hidden_inode) continue; IPUT(hidden_inode); } } KFREE(itohi_ptr(dentry->d_inode)); itohi_ptr(dentry->d_inode) = NULL; ibstart(dentry->d_inode) = -1; ibend(dentry->d_inode) = -1; up(&dentry->d_inode->i_sem); } result = unionfs_lookup_backend(dentry, interpose_flag); if (result) { if (IS_ERR(result)) { valid = 0; goto out; } /* current unionfs_lookup_backend() doesn't return a valid dentry */ DPUT(dentry); dentry = result; } if (positive && itopd(dentry->d_inode)->uii_stale) { make_stale_inode(dentry->d_inode); d_drop(dentry); valid = 0; goto out; } goto out; } /* The revalidation must occur across all branches */ bstart = dbstart(dentry); bend = dbend(dentry); BUG_ON(bstart == -1); for (bindex = bstart; bindex <= bend; bindex++) { hidden_dentry = dtohd_index(dentry, bindex); if (!hidden_dentry || !hidden_dentry->d_op || !hidden_dentry->d_op->d_revalidate) continue; if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd)) valid = 0; } if (!dentry->d_inode) valid = 0; if (valid) fist_copy_attr_all(dentry->d_inode, itohi(dentry->d_inode)); out: if (locked) unionfs_read_unlock(dentry->d_sb); fist_print_dentry("revalidate out", dentry); print_util_exit_status(valid); return valid; }
int copyup_named_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_hidden_dentry; struct dentry *old_hidden_dentry = NULL; struct super_block *sb; struct file *input_file = NULL; struct file *output_file = NULL; ssize_t read_bytes, write_bytes; mm_segment_t old_fs; int err = 0; char *buf; int old_bindex; int got_branch_input = -1; int got_branch_output = -1; int old_bstart; int old_bend; int size = len; struct dentry *new_hidden_parent_dentry = NULL; mm_segment_t oldfs; char *symbuf = NULL; uid_t saved_uid = current->fsuid; gid_t saved_gid = current->fsgid; print_entry_location(); verify_locked(dentry); fist_print_dentry("IN: copyup_named_dentry", 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; unionfs_read_lock(sb); if ((err = is_robranch_super(sb, new_bindex))) goto out; /* Create the directory structure above this dentry. */ new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex); if (IS_ERR(new_hidden_dentry)) { err = PTR_ERR(new_hidden_dentry); goto out; } fist_print_generic_dentry("Copyup Object", new_hidden_dentry); /* Now we actually create the object. */ old_hidden_dentry = dtohd_index(dentry, old_bindex); DGET(old_hidden_dentry); /* For symlinks, we must read the link before we lock the directory. */ if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) { symbuf = KMALLOC(PATH_MAX, GFP_KERNEL); if (!symbuf) { err = -ENOMEM; goto copyup_readlink_err; } oldfs = get_fs(); set_fs(KERNEL_DS); err = old_hidden_dentry->d_inode->i_op-> readlink(old_hidden_dentry, (char __user *)symbuf, PATH_MAX); set_fs(oldfs); if (err < 0) goto copyup_readlink_err; symbuf[err] = '\0'; } /* Now we lock the parent, and create the object in the new branch. */ new_hidden_parent_dentry = lock_parent(new_hidden_dentry); current->fsuid = new_hidden_parent_dentry->d_inode->i_uid; current->fsgid = new_hidden_parent_dentry->d_inode->i_gid; if (S_ISDIR(old_hidden_dentry->d_inode->i_mode)) { err = vfs_mkdir(new_hidden_parent_dentry->d_inode, new_hidden_dentry, S_IRWXU); } else if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) { err = vfs_symlink(new_hidden_parent_dentry->d_inode, new_hidden_dentry, symbuf, S_IRWXU); } else if (S_ISBLK(old_hidden_dentry->d_inode->i_mode) || S_ISCHR(old_hidden_dentry->d_inode->i_mode) || S_ISFIFO(old_hidden_dentry->d_inode->i_mode) || S_ISSOCK(old_hidden_dentry->d_inode->i_mode)) { err = vfs_mknod(new_hidden_parent_dentry->d_inode, new_hidden_dentry, old_hidden_dentry->d_inode->i_mode, old_hidden_dentry->d_inode->i_rdev); } else if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) { err = vfs_create(new_hidden_parent_dentry->d_inode, new_hidden_dentry, S_IRWXU, NULL); } else { char diemsg[100]; snprintf(diemsg, sizeof(diemsg), "Unknown inode type %d\n", old_hidden_dentry->d_inode->i_mode); printk(KERN_ERR "%s\n", diemsg); BUG(); } current->fsuid = saved_uid; current->fsgid = saved_gid; copyup_readlink_err: KFREE(symbuf); if (err) { /* get rid of the hidden dentry and all its traces */ DPUT(new_hidden_dentry); set_dtohd_index(dentry, new_bindex, NULL); set_dbstart(dentry, old_bstart); set_dbend(dentry, old_bend); goto out_dir; } #ifdef UNIONFS_IMAP if (stopd(sb)->usi_persistent) { err = write_uin(dentry->d_sb, dentry->d_inode->i_ino, new_bindex, new_hidden_dentry->d_inode->i_ino); if (err) goto out_dir; } #endif /* We actually copyup the file here. */ if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) { mntget(stohiddenmnt_index(sb, old_bindex)); branchget(sb, old_bindex); got_branch_input = old_bindex; input_file = DENTRY_OPEN(old_hidden_dentry, stohiddenmnt_index(sb, old_bindex), O_RDONLY); if (IS_ERR(input_file)) { err = PTR_ERR(input_file); goto out_dir; } if (!input_file->f_op || !input_file->f_op->read) { err = -EINVAL; goto out_dir; } /* copy the new file */ DGET(new_hidden_dentry); mntget(stohiddenmnt_index(sb, new_bindex)); branchget(sb, new_bindex); got_branch_output = new_bindex; output_file = DENTRY_OPEN(new_hidden_dentry, stohiddenmnt_index(sb, new_bindex), O_WRONLY); if (IS_ERR(output_file)) { err = PTR_ERR(output_file); goto out_dir; } if (!output_file->f_op || !output_file->f_op->write) { err = -EINVAL; goto out_dir; } /* allocating a buffer */ buf = (char *)KMALLOC(PAGE_SIZE, GFP_KERNEL); if (!buf) { err = -ENOMEM; goto out_dir; } /* now read PAGE_SIZE bytes from offset 0 in a loop */ old_fs = get_fs(); input_file->f_pos = 0; output_file->f_pos = 0; err = 0; // reset error just in case set_fs(KERNEL_DS); do { if (len >= PAGE_SIZE) size = PAGE_SIZE; else if ((len < PAGE_SIZE) && (len > 0)) size = len; len -= PAGE_SIZE; read_bytes = input_file->f_op->read(input_file, (char __user *)buf, size, &input_file->f_pos); if (read_bytes <= 0) { err = read_bytes; break; } write_bytes = output_file->f_op->write(output_file, (char __user *)buf, read_bytes, &output_file->f_pos); if (write_bytes < 0 || (write_bytes < read_bytes)) { err = write_bytes; break; } } while ((read_bytes > 0) && (len > 0)); set_fs(old_fs); KFREE(buf); if (err) { /* copyup failed, because we 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_hidden_parent_dentry->d_inode, new_hidden_dentry); goto out_dir; } } /* Set permissions. */ if ((err = copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry))) goto out_dir; /* Selinux uses extended attributes for permissions. */ if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry))) goto out_dir; /* do not allow files getting deleted to be reinterposed */ if (!d_deleted(dentry)) unionfs_reinterpose(dentry); out_dir: if (new_hidden_parent_dentry) unlock_dir(new_hidden_parent_dentry); out: if (input_file && !IS_ERR(input_file)) { fput(input_file); } else { /* since input file was not opened, we need to explicitly * dput the old_hidden_dentry */ DPUT(old_hidden_dentry); } /* in any case, we have to branchput */ if (got_branch_input >= 0) branchput(sb, got_branch_input); if (output_file) { if (copyup_file && !err) { *copyup_file = output_file; } else { /* close the file if there was no error, or if we ran * out of space in which case we unlinked the file */ if (!IS_ERR(output_file)) fput(output_file); branchput(sb, got_branch_output); } } unionfs_read_unlock(sb); fist_print_dentry("OUT: copyup_dentry", dentry); fist_print_inode("OUT: copyup_dentry", dentry->d_inode); print_exit_status(err); return err; }
static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir) { int err = 0; struct file *lower_file = NULL; struct dentry *dentry = file->f_path.dentry; struct dentry *parent; struct inode *inode = NULL; struct unionfs_getdents_callback buf; struct unionfs_dir_state *uds; int bend; loff_t offset; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT); parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT); unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); err = unionfs_file_revalidate(file, parent, false); if (unlikely(err)) goto out; inode = dentry->d_inode; uds = UNIONFS_F(file)->rdstate; if (!uds) { if (file->f_pos == DIREOF) { goto out; } else if (file->f_pos > 0) { uds = find_rdstate(inode, file->f_pos); if (unlikely(!uds)) { err = -ESTALE; goto out; } UNIONFS_F(file)->rdstate = uds; } else { init_rdstate(file); uds = UNIONFS_F(file)->rdstate; } } bend = fbend(file); while (uds->bindex <= bend) { lower_file = unionfs_lower_file_idx(file, uds->bindex); if (!lower_file) { uds->bindex++; uds->dirpos = 0; continue; } /* prepare callback buffer */ buf.filldir_called = 0; buf.filldir_error = 0; buf.entries_written = 0; buf.dirent = dirent; buf.filldir = filldir; buf.rdstate = uds; buf.sb = inode->i_sb; /* Read starting from where we last left off. */ offset = vfs_llseek(lower_file, uds->dirpos, SEEK_SET); if (offset < 0) { err = offset; goto out; } err = vfs_readdir(lower_file, unionfs_filldir, &buf); /* Save the position for when we continue. */ offset = vfs_llseek(lower_file, 0, SEEK_CUR); if (offset < 0) { err = offset; goto out; } uds->dirpos = offset; /* Copy the atime. */ fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode); if (err < 0) goto out; if (buf.filldir_error) break; if (!buf.entries_written) { uds->bindex++; uds->dirpos = 0; } } if (!buf.filldir_error && uds->bindex >= bend) { /* Save the number of hash entries for next time. */ UNIONFS_I(inode)->hashsize = uds->hashentries; free_rdstate(uds); UNIONFS_F(file)->rdstate = NULL; file->f_pos = DIREOF; } else { file->f_pos = rdstate2offset(uds); } out: if (!err) unionfs_check_file(file); unionfs_unlock_dentry(dentry); unionfs_unlock_parent(dentry, parent); unionfs_read_unlock(dentry->d_sb); return err; }
/* * returns 1 if valid, 0 otherwise. */ int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd) { int valid = 1; /* default is valid (1); invalid is 0. */ struct dentry *hidden_dentry; int bindex, bstart, bend; int sbgen, dgen; int positive = 0; int locked = 0; int restart = 0; int interpose_flag; struct nameidata lowernd; /* TODO: be gentler to the stack */ if (nd) memcpy(&lowernd, nd, sizeof(struct nameidata)); else memset(&lowernd, 0, sizeof(struct nameidata)); restart: verify_locked(dentry); /* if the dentry is unhashed, do NOT revalidate */ if (d_deleted(dentry)) { printk(KERN_DEBUG "unhashed dentry being revalidated: %*s\n", dentry->d_name.len, dentry->d_name.name); goto out; } BUG_ON(dbstart(dentry) == -1); if (dentry->d_inode) positive = 1; dgen = atomic_read(&UNIONFS_D(dentry)->generation); sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation); /* If we are working on an unconnected dentry, then there is no * revalidation to be done, because this file does not exist within the * namespace, and Unionfs operates on the namespace, not data. */ if (sbgen != dgen) { struct dentry *result; int pdgen; unionfs_read_lock(dentry->d_sb); locked = 1; /* The root entry should always be valid */ BUG_ON(IS_ROOT(dentry)); /* We can't work correctly if our parent isn't valid. */ pdgen = atomic_read(&UNIONFS_D(dentry->d_parent)->generation); if (!restart && (pdgen != sbgen)) { unionfs_read_unlock(dentry->d_sb); locked = 0; /* We must be locked before our parent. */ if (! (dentry->d_parent->d_op-> d_revalidate(dentry->d_parent, nd))) { valid = 0; goto out; } restart = 1; goto restart; } BUG_ON(pdgen != sbgen); /* Free the pointers for our inodes and this dentry. */ bstart = dbstart(dentry); bend = dbend(dentry); if (bstart >= 0) { struct dentry *hidden_dentry; for (bindex = bstart; bindex <= bend; bindex++) { hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); dput(hidden_dentry); } } set_dbstart(dentry, -1); set_dbend(dentry, -1); interpose_flag = INTERPOSE_REVAL_NEG; if (positive) { interpose_flag = INTERPOSE_REVAL; mutex_lock(&dentry->d_inode->i_mutex); bstart = ibstart(dentry->d_inode); bend = ibend(dentry->d_inode); if (bstart >= 0) { struct inode *hidden_inode; for (bindex = bstart; bindex <= bend; bindex++) { hidden_inode = unionfs_lower_inode_idx(dentry->d_inode, bindex); iput(hidden_inode); } } kfree(UNIONFS_I(dentry->d_inode)->lower_inodes); UNIONFS_I(dentry->d_inode)->lower_inodes = NULL; ibstart(dentry->d_inode) = -1; ibend(dentry->d_inode) = -1; mutex_unlock(&dentry->d_inode->i_mutex); } result = unionfs_lookup_backend(dentry, &lowernd, interpose_flag); if (result) { if (IS_ERR(result)) { valid = 0; goto out; } /* current unionfs_lookup_backend() doesn't return * a valid dentry */ dput(dentry); dentry = result; } if (positive && UNIONFS_I(dentry->d_inode)->stale) { make_bad_inode(dentry->d_inode); d_drop(dentry); valid = 0; goto out; } goto out; } /* The revalidation must occur across all branches */ bstart = dbstart(dentry); bend = dbend(dentry); BUG_ON(bstart == -1); for (bindex = bstart; bindex <= bend; bindex++) { hidden_dentry = unionfs_lower_dentry_idx(dentry, bindex); if (!hidden_dentry || !hidden_dentry->d_op || !hidden_dentry->d_op->d_revalidate) continue; if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd)) valid = 0; } if (!dentry->d_inode) valid = 0; if (valid) { fsstack_copy_attr_all(dentry->d_inode, unionfs_lower_inode(dentry->d_inode), unionfs_get_nlinks); fsstack_copy_inode_size(dentry->d_inode, unionfs_lower_inode(dentry->d_inode)); } out: if (locked) unionfs_read_unlock(dentry->d_sb); return valid; }