kernel/fs/libfs.c, branch linux-5.10.y

better lockdep annotations for simple_recursive_removal()

2025-08-28T14:22:40Z

[ Upstream commit 2a8061ee5e41034eb14170ec4517b5583dbeff9f ] We want a class that nests outside of I_MUTEX_NORMAL (for the sake of callbacks that might want to lock the victim) and inside I_MUTEX_PARENT (so that a variant of that could be used with parent of the victim held locked by the caller). In reality, simple_recursive_removal() * never holds two locks at once * holds the lock on parent of dentry passed to callback * is used only on the trees with fixed topology, so the depths are not changing. So the locking order is actually fine. AFAICS, the best solution is to assign I_MUTEX_CHILD to the locks grabbed by that thing. Reported-by: syzbot+169de184e9defe7fe709@syzkaller.appspotmail.com Signed-off-by: Al Viro Signed-off-by: Sasha Levin

libfs: add DEFINE_SIMPLE_ATTRIBUTE_SIGNED for signed value

2023-01-14T09:15:19Z

[ Upstream commit 2e41f274f9aa71cdcc69dc1f26a3f9304a651804 ] Patch series "fix error when writing negative value to simple attribute files". The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), but some attribute files want to accept a negative value. This patch (of 3): The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), so we have to use a 64-bit value to write a negative value. This adds DEFINE_SIMPLE_ATTRIBUTE_SIGNED for a signed value. Link: https://lkml.kernel.org/r/20220919172418.45257-1-akinobu.mita@gmail.com Link: https://lkml.kernel.org/r/20220919172418.45257-2-akinobu.mita@gmail.com Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Signed-off-by: Akinobu Mita Reported-by: Zhao Gongyi Reviewed-by: David Hildenbrand Reviewed-by: Greg Kroah-Hartman Cc: Alexander Viro Cc: Jonathan Corbet Cc: Oscar Salvador Cc: Rafael J. Wysocki Cc: Shuah Khan Cc: Wei Yongjun Cc: Yicong Yang Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

libfs: fix error cast of negative value in simple_attr_write()

2020-11-22T18:48:22Z

The attr->set() receive a value of u64, but simple_strtoll() is used for doing the conversion. It will lead to the error cast if user inputs a negative value. Use kstrtoull() instead of simple_strtoll() to convert a string got from the user to an unsigned value. The former will return '-EINVAL' if it gets a negetive value, but the latter can't handle the situation correctly. Make 'val' unsigned long long as what kstrtoull() takes, this will eliminate the compile warning on no 64-bit architectures. Fixes: f7b88631a897 ("fs/libfs.c: fix simple_attr_write() on 32bit machines") Signed-off-by: Yicong Yang Signed-off-by: Andrew Morton Cc: Al Viro Link: https://lkml.kernel.org/r/1605341356-11872-1-git-send-email-yangyicong@hisilicon.com Signed-off-by: Linus Torvalds

fs: Add standard casefolding support

2020-09-10T21:03:31Z

This adds general supporting functions for filesystems that use utf8 casefolding. It provides standard dentry_operations and adds the necessary structures in struct super_block to allow this standardization. The new dentry operations are functionally equivalent to the existing operations in ext4 and f2fs, apart from the use of utf8_casefold_hash to avoid an allocation. By providing a common implementation, all users can benefit from any optimizations without needing to port over improvements. Signed-off-by: Daniel Rosenberg Reviewed-by: Eric Biggers Signed-off-by: Jaegeuk Kim

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59Z

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

block: remove the error_sector argument to blkdev_issue_flush

2020-05-22T14:45:46Z

The argument isn't used by any caller, and drivers don't fill out bi_sector for flush requests either. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

libfs: fix infoleak in simple_attr_read()

2020-03-24T12:27:16Z

Reading from a debugfs file at a nonzero position, without first reading at position 0, leaks uninitialized memory to userspace. It's a bit tricky to do this, since lseek() and pread() aren't allowed on these files, and write() doesn't update the position on them. But writing to them with splice() *does* update the position: #define _GNU_SOURCE 1 #include #include #include int main() { int pipes[2], fd, n, i; char buf[32]; pipe(pipes); write(pipes[1], "0", 1); fd = open("/sys/kernel/debug/fault_around_bytes", O_RDWR); splice(pipes[0], NULL, fd, NULL, 1, 0); n = read(fd, buf, sizeof(buf)); for (i = 0; i < n; i++) printf("%02x", buf[i]); printf("\n"); } Output: 5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a30 Fix the infoleak by making simple_attr_read() always fill simple_attr::get_buf if it hasn't been filled yet. Reported-by: syzbot+fcab69d1ada3e8d6f06b@syzkaller.appspotmail.com Reported-by: Alexander Potapenko Fixes: acaefc25d21f ("[PATCH] libfs: add simple attribute files") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Acked-by: Kees Cook Link: https://lore.kernel.org/r/20200308023849.988264-1-ebiggers@kernel.org Signed-off-by: Greg Kroah-Hartman

simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems

2019-12-11T03:29:58Z

two requirements: no file creations in IS_DEADDIR and no cross-directory renames whatsoever. Signed-off-by: Al Viro

fs/libfs.c: fix kernel-doc warning

2019-10-14T22:04:01Z

Fix kernel-doc warning in fs/libfs.c: fs/libfs.c:496: warning: Excess function parameter 'available' description in 'simple_write_end' Link: http://lkml.kernel.org/r/5fc9d70b-e377-0ec9-066a-970d49579041@infradead.org Fixes: ad2a722f196d ("libfs: Open code simple_commit_write into only user") Signed-off-by: Randy Dunlap Cc: Boaz Harrosh Cc: Alexander Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

libfs: take cursors out of list when moving past the end of directory

2019-10-10T02:57:30Z

that eliminates the last place where we accessed the tail of ->d_subdirs Signed-off-by: Al Viro