linux/fs/readdir.c, branch v6.17

readdir: supply dir_context.count as readdir buffer size hint

2025-05-15T09:26:05Z

This is a preparation for large readdir buffers in fuse. Simply setting the fuse buffer size to the userspace buffer size should work, the record sizes are similar (fuse's is slightly larger than libc's, so no overflow should ever happen). Signed-off-by: Miklos Szeredi Signed-off-by: Jaco Kroon Link: https://lore.kernel.org/20250513151012.1476536-1-mszeredi@redhat.com Signed-off-by: Christian Brauner

fuse: don't allow signals to interrupt getdents copying

2025-05-15T09:12:11Z

When getting the directory contents, the entries are first fetched to a kernel buffer, then they are copied to userspace with dir_emit(). This second phase is non-blocking as long as the userspace buffer is not paged out, making it interruptible makes zero sense. Overload d_type as flags, since it only uses 4 bits from 32. Reviewed-by: Bernd Schubert Signed-off-by: Miklos Szeredi Link: https://lore.kernel.org/20250513112335.1473177-1-mszeredi@redhat.com Signed-off-by: Christian Brauner

introduce "fd_pos" class, convert fdget_pos() users to it.

2024-11-03T06:28:06Z

fdget_pos() for constructor, fdput_pos() for cleanup, all users of fd..._pos() converted trivially. Reviewed-by: Christian Brauner Signed-off-by: Al Viro

introduce fd_file(), convert all accessors to it.

2024-08-13T02:00:43Z

For any changes of struct fd representation we need to turn existing accesses to fields into calls of wrappers. Accesses to struct fd::flags are very few (3 in linux/file.h, 1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in explicit initializers). Those can be dealt with in the commit converting to new layout; accesses to struct fd::file are too many for that. This commit converts (almost) all of f.file to fd_file(f). It's not entirely mechanical ('file' is used as a member name more than just in struct fd) and it does not even attempt to distinguish the uses in pointer context from those in boolean context; the latter will be eventually turned into a separate helper (fd_empty()). NOTE: mass conversion to fd_empty(), tempting as it might be, is a bad idea; better do that piecewise in commit that convert from fdget...() to CLASS(...). [conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c caught by git; fs/stat.c one got caught by git grep] [fs/xattr.c conflict] Reviewed-by: Christian Brauner Signed-off-by: Al Viro

readdir: Add missing quote in macro comment

2024-06-03T13:49:26Z

Add a missing double quote in the unsafe_copy_dirent_name() macro comment. Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20240602004729.229634-2-thorsten.blum@toblux.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

readdir: Remove unused header include

2024-06-03T13:48:39Z

Since commit c512c6918719 ("uaccess: implement a proper unsafe_copy_to_user() and switch filldir over to it") the header file is no longer needed. Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20240602101534.348159-2-thorsten.blum@toblux.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

fsnotify: optionally pass access range in file permission hooks

2023-12-12T15:20:02Z

In preparation for pre-content permission events with file access range, move fsnotify_file_perm() hook out of security_file_permission() and into the callers. Callers that have the access range information call the new hook fsnotify_file_area_perm() with the access range. Reviewed-by: Jan Kara Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/r/20231212094440.250945-6-amir73il@gmail.com Signed-off-by: Christian Brauner

vfs: get rid of old '->iterate' directory operation

2023-08-06T13:08:35Z

All users now just use '->iterate_shared()', which only takes the directory inode lock for reading. Filesystems that never got convered to shared mode now instead use a wrapper that drops the lock, re-takes it in write mode, calls the old function, and then downgrades the lock back to read mode. This way the VFS layer and other callers no longer need to care about filesystems that never got converted to the modern era. The filesystems that use the new wrapper are ceph, coda, exfat, jfs, ntfs, ocfs2, overlayfs, and vboxsf. Honestly, several of them look like they really could just iterate their directories in shared mode and skip the wrapper entirely, but the point of this change is to not change semantics or fix filesystems that haven't been fixed in the last 7+ years, but to finally get rid of the dual iterators. Signed-off-by: Linus Torvalds Signed-off-by: Christian Brauner

readdir: Replace one-element arrays with flexible-array members

2023-06-21T07:06:59Z

One-element arrays are deprecated, and we are replacing them with flexible array members instead. So, replace one-element arrays with flexible-array members in multiple structures. Address the following -Wstringop-overflow warnings seen when built m68k architecture with m5307c3_defconfig configuration: In function '__put_user_fn', inlined from 'fillonedir' at fs/readdir.c:170:2: include/asm-generic/uaccess.h:49:35: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] 49 | *(u8 __force *)to = *(u8 *)from; | ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~ fs/readdir.c: In function 'fillonedir': fs/readdir.c:134:25: note: at offset 1 into destination object 'd_name' of size 1 134 | char d_name[1]; | ^~~~~~ In function '__put_user_fn', inlined from 'filldir' at fs/readdir.c:257:2: include/asm-generic/uaccess.h:49:35: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=] 49 | *(u8 __force *)to = *(u8 *)from; | ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~ fs/readdir.c: In function 'filldir': fs/readdir.c:211:25: note: at offset 1 into destination object 'd_name' of size 1 211 | char d_name[1]; | ^~~~~~ This helps with the ongoing efforts to globally enable -Wstringop-overflow. This results in no differences in binary output. Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/312 Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook Message-Id: Signed-off-by: Christian Brauner

Change calling conventions for filldir_t

2022-08-17T21:25:04Z

filldir_t instances (directory iterators callbacks) used to return 0 for "OK, keep going" or -E... for "stop". Note that it's *NOT* how the error values are reported - the rules for those are callback-dependent and ->iterate{,_shared}() instances only care about zero vs. non-zero (look at emit_dir() and friends). So let's just return bool ("should we keep going?") - it's less confusing that way. The choice between "true means keep going" and "true means stop" is bikesheddable; we have two groups of callbacks - do something for everything in directory, until we run into problem and find an entry in directory and do something to it. The former tended to use 0/-E... conventions - -E on failure. The latter tended to use 0/1, 1 being "stop, we are done". The callers treated anything non-zero as "stop", ignoring which non-zero value did they get. "true means stop" would be more natural for the second group; "true means keep going" - for the first one. I tried both variants and the things like if allocation failed something = -ENOMEM; return true; just looked unnatural and asking for trouble. [folded suggestion from Matthew Wilcox ] Acked-by: Christian Brauner (Microsoft) Signed-off-by: Al Viro