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/remap_range.c | 567 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 567 insertions(+) create mode 100644 fs/remap_range.c (limited to 'fs/remap_range.c') diff --git a/fs/remap_range.c b/fs/remap_range.c new file mode 100644 index 000000000..26afbbbfb --- /dev/null +++ b/fs/remap_range.c @@ -0,0 +1,567 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +#include +#include + +/* + * Performs necessary checks before doing a clone. + * + * Can adjust amount of bytes to clone via @req_count argument. + * Returns appropriate error code that caller should return or + * zero in case the clone should be allowed. + */ +static int generic_remap_checks(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *req_count, unsigned int remap_flags) +{ + struct inode *inode_in = file_in->f_mapping->host; + struct inode *inode_out = file_out->f_mapping->host; + uint64_t count = *req_count; + uint64_t bcount; + loff_t size_in, size_out; + loff_t bs = inode_out->i_sb->s_blocksize; + int ret; + + /* The start of both ranges must be aligned to an fs block. */ + if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs)) + return -EINVAL; + + /* Ensure offsets don't wrap. */ + if (pos_in + count < pos_in || pos_out + count < pos_out) + return -EINVAL; + + size_in = i_size_read(inode_in); + size_out = i_size_read(inode_out); + + /* Dedupe requires both ranges to be within EOF. */ + if ((remap_flags & REMAP_FILE_DEDUP) && + (pos_in >= size_in || pos_in + count > size_in || + pos_out >= size_out || pos_out + count > size_out)) + return -EINVAL; + + /* Ensure the infile range is within the infile. */ + if (pos_in >= size_in) + return -EINVAL; + count = min(count, size_in - (uint64_t)pos_in); + + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + + /* + * If the user wanted us to link to the infile's EOF, round up to the + * next block boundary for this check. + * + * Otherwise, make sure the count is also block-aligned, having + * already confirmed the starting offsets' block alignment. + */ + if (pos_in + count == size_in && + (!(remap_flags & REMAP_FILE_DEDUP) || pos_out + count == size_out)) { + bcount = ALIGN(size_in, bs) - pos_in; + } else { + if (!IS_ALIGNED(count, bs)) + count = ALIGN_DOWN(count, bs); + bcount = count; + } + + /* Don't allow overlapped cloning within the same file. */ + if (inode_in == inode_out && + pos_out + bcount > pos_in && + pos_out < pos_in + bcount) + return -EINVAL; + + /* + * We shortened the request but the caller can't deal with that, so + * bounce the request back to userspace. + */ + if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN)) + return -EINVAL; + + *req_count = count; + return 0; +} + +int remap_verify_area(struct file *file, loff_t pos, loff_t len, bool write) +{ + int mask = write ? MAY_WRITE : MAY_READ; + loff_t tmp; + int ret; + + if (unlikely(pos < 0 || len < 0)) + return -EINVAL; + + if (unlikely(check_add_overflow(pos, len, &tmp))) + return -EINVAL; + + ret = security_file_permission(file, mask); + if (ret) + return ret; + + return fsnotify_file_area_perm(file, mask, &pos, len); +} +EXPORT_SYMBOL_GPL(remap_verify_area); + +/* + * Ensure that we don't remap a partial EOF block in the middle of something + * else. Assume that the offsets have already been checked for block + * alignment. + * + * For clone we only link a partial EOF block above or at the destination file's + * EOF. For deduplication we accept a partial EOF block only if it ends at the + * destination file's EOF (can not link it into the middle of a file). + * + * Shorten the request if possible. + */ +static int generic_remap_check_len(struct inode *inode_in, + struct inode *inode_out, + loff_t pos_out, + loff_t *len, + unsigned int remap_flags) +{ + u64 blkmask = i_blocksize(inode_in) - 1; + loff_t new_len = *len; + + if ((*len & blkmask) == 0) + return 0; + + if (pos_out + *len < i_size_read(inode_out)) + new_len &= ~blkmask; + + if (new_len == *len) + return 0; + + if (remap_flags & REMAP_FILE_CAN_SHORTEN) { + *len = new_len; + return 0; + } + + return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL; +} + +/* Read a page's worth of file data into the page cache. */ +static struct folio *vfs_dedupe_get_folio(struct file *file, loff_t pos) +{ + return read_mapping_folio(file->f_mapping, pos >> PAGE_SHIFT, file); +} + +/* + * Lock two folios, ensuring that we lock in offset order if the folios + * are from the same file. + */ +static void vfs_lock_two_folios(struct folio *folio1, struct folio *folio2) +{ + /* Always lock in order of increasing index. */ + if (folio1->index > folio2->index) + swap(folio1, folio2); + + folio_lock(folio1); + if (folio1 != folio2) + folio_lock(folio2); +} + +/* Unlock two folios, being careful not to unlock the same folio twice. */ +static void vfs_unlock_two_folios(struct folio *folio1, struct folio *folio2) +{ + folio_unlock(folio1); + if (folio1 != folio2) + folio_unlock(folio2); +} + +/* + * Compare extents of two files to see if they are the same. + * Caller must have locked both inodes to prevent write races. + */ +static int vfs_dedupe_file_range_compare(struct file *src, loff_t srcoff, + struct file *dest, loff_t dstoff, + loff_t len, bool *is_same) +{ + bool same = true; + int error = -EINVAL; + + while (len) { + struct folio *src_folio, *dst_folio; + void *src_addr, *dst_addr; + loff_t cmp_len = min(PAGE_SIZE - offset_in_page(srcoff), + PAGE_SIZE - offset_in_page(dstoff)); + + cmp_len = min(cmp_len, len); + if (cmp_len <= 0) + goto out_error; + + src_folio = vfs_dedupe_get_folio(src, srcoff); + if (IS_ERR(src_folio)) { + error = PTR_ERR(src_folio); + goto out_error; + } + dst_folio = vfs_dedupe_get_folio(dest, dstoff); + if (IS_ERR(dst_folio)) { + error = PTR_ERR(dst_folio); + folio_put(src_folio); + goto out_error; + } + + vfs_lock_two_folios(src_folio, dst_folio); + + /* + * Now that we've locked both folios, make sure they're still + * mapped to the file data we're interested in. If not, + * someone is invalidating pages on us and we lose. + */ + if (!folio_test_uptodate(src_folio) || !folio_test_uptodate(dst_folio) || + src_folio->mapping != src->f_mapping || + dst_folio->mapping != dest->f_mapping) { + same = false; + goto unlock; + } + + src_addr = kmap_local_folio(src_folio, + offset_in_folio(src_folio, srcoff)); + dst_addr = kmap_local_folio(dst_folio, + offset_in_folio(dst_folio, dstoff)); + + flush_dcache_folio(src_folio); + flush_dcache_folio(dst_folio); + + if (memcmp(src_addr, dst_addr, cmp_len)) + same = false; + + kunmap_local(dst_addr); + kunmap_local(src_addr); +unlock: + vfs_unlock_two_folios(src_folio, dst_folio); + folio_put(dst_folio); + folio_put(src_folio); + + if (!same) + break; + + srcoff += cmp_len; + dstoff += cmp_len; + len -= cmp_len; + } + + *is_same = same; + return 0; + +out_error: + return error; +} + +/* + * Check that the two inodes are eligible for cloning, the ranges make + * sense, and then flush all dirty data. Caller must ensure that the + * inodes have been locked against any other modifications. + * + * If there's an error, then the usual negative error code is returned. + * Otherwise returns 0 with *len set to the request length. + */ +int +__generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *len, unsigned int remap_flags, + const struct iomap_ops *dax_read_ops) +{ + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); + bool same_inode = (inode_in == inode_out); + int ret; + + /* Don't touch certain kinds of inodes */ + if (IS_IMMUTABLE(inode_out)) + return -EPERM; + + if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) + return -ETXTBSY; + + /* Don't reflink dirs, pipes, sockets... */ + if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) + return -EISDIR; + if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) + return -EINVAL; + + /* Zero length dedupe exits immediately; reflink goes to EOF. */ + if (*len == 0) { + loff_t isize = i_size_read(inode_in); + + if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize) + return 0; + if (pos_in > isize) + return -EINVAL; + *len = isize - pos_in; + if (*len == 0) + return 0; + } + + /* Check that we don't violate system file offset limits. */ + ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len, + remap_flags); + if (ret || *len == 0) + return ret; + + /* Wait for the completion of any pending IOs on both files */ + inode_dio_wait(inode_in); + if (!same_inode) + inode_dio_wait(inode_out); + + ret = filemap_write_and_wait_range(inode_in->i_mapping, + pos_in, pos_in + *len - 1); + if (ret) + return ret; + + ret = filemap_write_and_wait_range(inode_out->i_mapping, + pos_out, pos_out + *len - 1); + if (ret) + return ret; + + /* + * Check that the extents are the same. + */ + if (remap_flags & REMAP_FILE_DEDUP) { + bool is_same = false; + + if (!IS_DAX(inode_in)) + ret = vfs_dedupe_file_range_compare(file_in, pos_in, + file_out, pos_out, *len, &is_same); + else if (dax_read_ops) + ret = dax_dedupe_file_range_compare(inode_in, pos_in, + inode_out, pos_out, *len, &is_same, + dax_read_ops); + else + return -EINVAL; + if (ret) + return ret; + if (!is_same) + return -EBADE; + } + + ret = generic_remap_check_len(inode_in, inode_out, pos_out, len, + remap_flags); + if (ret || *len == 0) + return ret; + + /* If can't alter the file contents, we're done. */ + if (!(remap_flags & REMAP_FILE_DEDUP)) + ret = file_modified(file_out); + + return ret; +} + +int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *len, unsigned int remap_flags) +{ + return __generic_remap_file_range_prep(file_in, pos_in, file_out, + pos_out, len, remap_flags, NULL); +} +EXPORT_SYMBOL(generic_remap_file_range_prep); + +loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t len, unsigned int remap_flags) +{ + loff_t ret; + + WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP); + + if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) + return -EXDEV; + + ret = generic_file_rw_checks(file_in, file_out); + if (ret < 0) + return ret; + + if (!file_in->f_op->remap_file_range) + return -EOPNOTSUPP; + + ret = remap_verify_area(file_in, pos_in, len, false); + if (ret) + return ret; + + ret = remap_verify_area(file_out, pos_out, len, true); + if (ret) + return ret; + + file_start_write(file_out); + ret = file_in->f_op->remap_file_range(file_in, pos_in, + file_out, pos_out, len, remap_flags); + file_end_write(file_out); + if (ret < 0) + return ret; + + fsnotify_access(file_in); + fsnotify_modify(file_out); + return ret; +} +EXPORT_SYMBOL(vfs_clone_file_range); + +/* Check whether we are allowed to dedupe the destination file */ +static bool may_dedupe_file(struct file *file) +{ + struct mnt_idmap *idmap = file_mnt_idmap(file); + struct inode *inode = file_inode(file); + + if (capable(CAP_SYS_ADMIN)) + return true; + if (file->f_mode & FMODE_WRITE) + return true; + if (vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), current_fsuid())) + return true; + if (!inode_permission(idmap, inode, MAY_WRITE)) + return true; + return false; +} + +loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos, + struct file *dst_file, loff_t dst_pos, + loff_t len, unsigned int remap_flags) +{ + loff_t ret; + + WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP | + REMAP_FILE_CAN_SHORTEN)); + + /* + * This is redundant if called from vfs_dedupe_file_range(), but other + * callers need it and it's not performance sesitive... + */ + ret = remap_verify_area(src_file, src_pos, len, false); + if (ret) + return ret; + + ret = remap_verify_area(dst_file, dst_pos, len, true); + if (ret) + return ret; + + /* + * This needs to be called after remap_verify_area() because of + * sb_start_write() and before may_dedupe_file() because the mount's + * MAY_WRITE need to be checked with mnt_get_write_access_file() held. + */ + ret = mnt_want_write_file(dst_file); + if (ret) + return ret; + + ret = -EPERM; + if (!may_dedupe_file(dst_file)) + goto out_drop_write; + + ret = -EXDEV; + if (file_inode(src_file)->i_sb != file_inode(dst_file)->i_sb) + goto out_drop_write; + + ret = -EISDIR; + if (S_ISDIR(file_inode(dst_file)->i_mode)) + goto out_drop_write; + + ret = -EINVAL; + if (!dst_file->f_op->remap_file_range) + goto out_drop_write; + + if (len == 0) { + ret = 0; + goto out_drop_write; + } + + ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file, + dst_pos, len, remap_flags | REMAP_FILE_DEDUP); +out_drop_write: + mnt_drop_write_file(dst_file); + + return ret; +} +EXPORT_SYMBOL(vfs_dedupe_file_range_one); + +int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) +{ + struct file_dedupe_range_info *info; + struct inode *src = file_inode(file); + u64 off; + u64 len; + int i; + int ret; + u16 count = same->dest_count; + loff_t deduped; + + if (!(file->f_mode & FMODE_READ)) + return -EINVAL; + + if (same->reserved1 || same->reserved2) + return -EINVAL; + + off = same->src_offset; + len = same->src_length; + + if (S_ISDIR(src->i_mode)) + return -EISDIR; + + if (!S_ISREG(src->i_mode)) + return -EINVAL; + + if (!file->f_op->remap_file_range) + return -EOPNOTSUPP; + + ret = remap_verify_area(file, off, len, false); + if (ret < 0) + return ret; + ret = 0; + + if (off + len > i_size_read(src)) + return -EINVAL; + + /* Arbitrary 1G limit on a single dedupe request, can be raised. */ + len = min_t(u64, len, 1 << 30); + + /* pre-format output fields to sane values */ + for (i = 0; i < count; i++) { + same->info[i].bytes_deduped = 0ULL; + same->info[i].status = FILE_DEDUPE_RANGE_SAME; + } + + for (i = 0, info = same->info; i < count; i++, info++) { + CLASS(fd, dst_fd)(info->dest_fd); + + if (fd_empty(dst_fd)) { + info->status = -EBADF; + goto next_loop; + } + + if (info->reserved) { + info->status = -EINVAL; + goto next_loop; + } + + deduped = vfs_dedupe_file_range_one(file, off, fd_file(dst_fd), + info->dest_offset, len, + REMAP_FILE_CAN_SHORTEN); + if (deduped == -EBADE) + info->status = FILE_DEDUPE_RANGE_DIFFERS; + else if (deduped < 0) + info->status = deduped; + else + info->bytes_deduped = len; + +next_loop: + if (fatal_signal_pending(current)) + break; + } + return ret; +} +EXPORT_SYMBOL(vfs_dedupe_file_range); -- cgit v1.3.1