From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- fs/btrfs/export.c | 307 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 307 insertions(+) create mode 100644 fs/btrfs/export.c (limited to 'fs/btrfs/export.c') diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c new file mode 100644 index 000000000..230d9326b --- /dev/null +++ b/fs/btrfs/export.c @@ -0,0 +1,307 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include "ctree.h" +#include "disk-io.h" +#include "btrfs_inode.h" +#include "export.h" +#include "accessors.h" +#include "super.h" + +#define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \ + parent_objectid) / 4) +#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \ + parent_root_objectid) / 4) +#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4) + +static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len, + struct inode *parent) +{ + struct btrfs_fid *fid = (struct btrfs_fid *)fh; + int len = *max_len; + int type; + + if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) { + if (btrfs_root_id(BTRFS_I(inode)->root) != + btrfs_root_id(BTRFS_I(parent)->root)) + *max_len = BTRFS_FID_SIZE_CONNECTABLE_ROOT; + else + *max_len = BTRFS_FID_SIZE_CONNECTABLE; + return FILEID_INVALID; + } else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) { + *max_len = BTRFS_FID_SIZE_NON_CONNECTABLE; + return FILEID_INVALID; + } + + len = BTRFS_FID_SIZE_NON_CONNECTABLE; + type = FILEID_BTRFS_WITHOUT_PARENT; + + fid->objectid = btrfs_ino(BTRFS_I(inode)); + fid->root_objectid = btrfs_root_id(BTRFS_I(inode)->root); + fid->gen = inode->i_generation; + + if (parent) { + u64 parent_root_id; + + fid->parent_objectid = btrfs_ino(BTRFS_I(parent)); + fid->parent_gen = parent->i_generation; + parent_root_id = btrfs_root_id(BTRFS_I(parent)->root); + + if (parent_root_id != fid->root_objectid) { + if (*max_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) + return FILEID_INVALID; + fid->parent_root_objectid = parent_root_id; + len = BTRFS_FID_SIZE_CONNECTABLE_ROOT; + type = FILEID_BTRFS_WITH_PARENT_ROOT; + } else { + len = BTRFS_FID_SIZE_CONNECTABLE; + type = FILEID_BTRFS_WITH_PARENT; + } + } + + *max_len = len; + return type; +} + +/* + * Read dentry of inode with @objectid from filesystem root @root_objectid. + * + * @sb: the filesystem super block + * @objectid: inode objectid + * @root_objectid: object id of the subvolume root where to look up the inode + * @generation: optional, if not zero, verify that the found inode + * generation matches + * + * Return dentry alias for the inode, otherwise an error. In case the + * generation does not match return ESTALE. + */ +struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, + u64 root_objectid, u64 generation) +{ + struct btrfs_fs_info *fs_info = btrfs_sb(sb); + struct btrfs_root *root; + struct btrfs_inode *inode; + + if (objectid < BTRFS_FIRST_FREE_OBJECTID) + return ERR_PTR(-ESTALE); + + root = btrfs_get_fs_root(fs_info, root_objectid, true); + if (IS_ERR(root)) + return ERR_CAST(root); + + inode = btrfs_iget(objectid, root); + btrfs_put_root(root); + if (IS_ERR(inode)) + return ERR_CAST(inode); + + if (generation != 0 && generation != inode->vfs_inode.i_generation) { + iput(&inode->vfs_inode); + return ERR_PTR(-ESTALE); + } + + return d_obtain_alias(&inode->vfs_inode); +} + +static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh, + int fh_len, int fh_type) +{ + struct btrfs_fid *fid = (struct btrfs_fid *) fh; + u64 objectid, root_objectid; + u32 generation; + + if (fh_type == FILEID_BTRFS_WITH_PARENT) { + if (fh_len < BTRFS_FID_SIZE_CONNECTABLE) + return NULL; + root_objectid = fid->root_objectid; + } else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) { + if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) + return NULL; + root_objectid = fid->parent_root_objectid; + } else + return NULL; + + objectid = fid->parent_objectid; + generation = fid->parent_gen; + + return btrfs_get_dentry(sb, objectid, root_objectid, generation); +} + +static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh, + int fh_len, int fh_type) +{ + struct btrfs_fid *fid = (struct btrfs_fid *) fh; + u64 objectid, root_objectid; + u32 generation; + + if ((fh_type != FILEID_BTRFS_WITH_PARENT || + fh_len < BTRFS_FID_SIZE_CONNECTABLE) && + (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT || + fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) && + (fh_type != FILEID_BTRFS_WITHOUT_PARENT || + fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE)) + return NULL; + + objectid = fid->objectid; + root_objectid = fid->root_objectid; + generation = fid->gen; + + return btrfs_get_dentry(sb, objectid, root_objectid, generation); +} + +struct dentry *btrfs_get_parent(struct dentry *child) +{ + struct btrfs_inode *dir = BTRFS_I(d_inode(child)); + struct btrfs_inode *inode; + struct btrfs_root *root = dir->root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_root_ref *ref; + struct btrfs_key key; + struct btrfs_key found_key; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return ERR_PTR(-ENOMEM); + + if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) { + key.objectid = btrfs_root_id(root); + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = (u64)-1; + root = fs_info->tree_root; + } else { + key.objectid = btrfs_ino(dir); + key.type = BTRFS_INODE_REF_KEY; + key.offset = (u64)-1; + } + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto fail; + if (unlikely(ret == 0)) { + /* + * Key with offset of -1 found, there would have to exist an + * inode with such number or a root with such id. + */ + ret = -EUCLEAN; + goto fail; + } + + if (path->slots[0] == 0) { + ret = -ENOENT; + goto fail; + } + + path->slots[0]--; + leaf = path->nodes[0]; + + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.objectid != key.objectid || found_key.type != key.type) { + ret = -ENOENT; + goto fail; + } + + if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { + ref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_root_ref); + key.objectid = btrfs_root_ref_dirid(leaf, ref); + } else { + key.objectid = found_key.offset; + } + btrfs_free_path(path); + + if (found_key.type == BTRFS_ROOT_BACKREF_KEY) { + return btrfs_get_dentry(fs_info->sb, key.objectid, + found_key.offset, 0); + } + + inode = btrfs_iget(key.objectid, root); + if (IS_ERR(inode)) + return ERR_CAST(inode); + + return d_obtain_alias(&inode->vfs_inode); +fail: + btrfs_free_path(path); + return ERR_PTR(ret); +} + +static int btrfs_get_name(struct dentry *parent, char *name, + struct dentry *child) +{ + struct btrfs_inode *inode = BTRFS_I(d_inode(child)); + struct btrfs_inode *dir = BTRFS_I(d_inode(parent)); + struct btrfs_root *root = dir->root; + struct btrfs_fs_info *fs_info = root->fs_info; + BTRFS_PATH_AUTO_FREE(path); + struct btrfs_inode_ref *iref; + struct btrfs_root_ref *rref; + struct extent_buffer *leaf; + unsigned long name_ptr; + struct btrfs_key key; + int name_len; + int ret; + u64 ino; + + if (!S_ISDIR(dir->vfs_inode.i_mode)) + return -EINVAL; + + ino = btrfs_ino(inode); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + if (ino == BTRFS_FIRST_FREE_OBJECTID) { + key.objectid = btrfs_root_id(inode->root); + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = (u64)-1; + root = fs_info->tree_root; + } else { + key.objectid = ino; + key.type = BTRFS_INODE_REF_KEY; + key.offset = btrfs_ino(dir); + } + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + return ret; + } else if (ret > 0) { + if (ino == BTRFS_FIRST_FREE_OBJECTID) + path->slots[0]--; + else + return -ENOENT; + } + leaf = path->nodes[0]; + + if (ino == BTRFS_FIRST_FREE_OBJECTID) { + rref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_root_ref); + name_ptr = (unsigned long)(rref + 1); + name_len = btrfs_root_ref_name_len(leaf, rref); + } else { + iref = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_inode_ref); + name_ptr = (unsigned long)(iref + 1); + name_len = btrfs_inode_ref_name_len(leaf, iref); + } + + read_extent_buffer(leaf, name, name_ptr, name_len); + + /* + * have to add the null termination to make sure that reconnect_path + * gets the right len for strlen + */ + name[name_len] = '\0'; + + return 0; +} + +const struct export_operations btrfs_export_ops = { + .encode_fh = btrfs_encode_fh, + .fh_to_dentry = btrfs_fh_to_dentry, + .fh_to_parent = btrfs_fh_to_parent, + .get_parent = btrfs_get_parent, + .get_name = btrfs_get_name, +}; -- cgit v1.3.1