user/sven/linux.git/fs/debugfs, branch v6.16.1

VFS: rename lookup_one_len family to lookup_noperm and remove permission check

2025-04-08T09:24:36Z

The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner

debugfs: Fix the missing initializations in __debugfs_file_get()

2025-01-30T07:22:31Z

both method table pointers in debugfs_fsdata need to be initialized, obviously, and calculating the bitmap of present methods would also go better if we start with initialized state. Fixes: 41a0ecc0997c ("debugfs: get rid of dynamically allocation proxy_ops") Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250129191937.GR1977892@ZenIV Signed-off-by: Greg Kroah-Hartman

saner replacement for debugfs_rename()

2025-01-15T12:14:37Z

Existing primitive has several problems: 1) calling conventions are clumsy - it returns a dentry reference that is either identical to its second argument or is an ERR_PTR(-E...); in both cases no refcount changes happen. Inconvenient for users and bug-prone; it would be better to have it return 0 on success and -E... on failure. 2) it allows cross-directory moves; however, no such caller have ever materialized and considering the way debugfs is used, it's unlikely to happen in the future. What's more, any such caller would have fun issues to deal with wrt interplay with recursive removal. It also makes the calling conventions clumsier... 3) tautological rename fails; the callers have no race-free way to deal with that. 4) new name must have been formed by the caller; quite a few callers have it done by sprintf/kasprintf/etc., ending up with considerable boilerplate. Proposed replacement: int debugfs_change_name(dentry, fmt, ...). All callers convert to that easily, and it's simpler internally. IMO debugfs_rename() should go; if we ever get a real-world use case for cross-directory moves in debugfs, we can always look into the right way to handle that. Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20250112080705.141166-21-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: allow to store an additional opaque pointer at file creation

2025-01-15T12:14:36Z

Set by debugfs_create_file_aux(name, mode, parent, data, aux, fops). Plain debugfs_create_file() has it set to NULL. Accessed by debugfs_get_aux(file). Convenience macros for numeric opaque data - debugfs_create_file_aux_num and debugfs_get_aux_num, resp. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-5-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: don't mess with bits in ->d_fsdata

2025-01-15T12:14:35Z

The reason we need that crap is the dual use ->d_fsdata has there - it's both holding a debugfs_fsdata reference after the first debugfs_file_get() (actually, after the call of proxy ->open()) *and* it serves as a place to stash a reference to real file_operations from object creation to the first open. Oh, and it's triple use, actually - that stashed reference might be to debugfs_short_fops. Bugger that for a game of solidiers - just put the operations reference into debugfs-private augmentation of inode. And split debugfs_full_file_operations into full and short cases, so that debugfs_get_file() could tell one from another. Voila - ->d_fsdata holds NULL until the first (successful) debugfs_get_file() and a reference to struct debugfs_fsdata afterwards. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-4-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: get rid of dynamically allocation proxy_ops

2025-01-15T12:14:35Z

All it takes is having full_proxy_open() collect the information about available methods and store it in debugfs_fsdata. Wrappers are called only after full_proxy_open() has succeeded calling debugfs_get_file(), so they are guaranteed to have ->d_fsdata already pointing to debugfs_fsdata. As the result, they can check if method is absent and bugger off early, without any atomic operations, etc. - same effect as what we'd have from NULL method. Which makes the entire proxy_fops contents unconditional, making it completely pointless - we can just put those methods (unconditionally) into debugfs_full_proxy_file_operations and forget about dynamic allocation, replace_fops, etc. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-3-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: move ->automount into debugfs_inode_info

2025-01-15T12:14:35Z

... and don't bother with debugfs_fsdata for those. Life's simpler that way... Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-2-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

debugfs: separate cache for debugfs inodes

2025-01-15T12:14:35Z

Embed them into container (struct debugfs_inode_info, with nothing else in it at the moment), set the cache up, etc. Just the infrastructure changes letting us augment debugfs inodes here; adding stuff will come at the next step. Signed-off-by: Al Viro Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20250112080705.141166-1-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman

fs: debugfs: fix open proxy for unsafe files

2025-01-10T08:41:53Z

In the previous commit referenced below, I had to split the short fops handling into different proxy fops. This necessitated knowing out-of-band whether or not the ops are short or full, when attempting to convert from fops to allocated fsdata. Unfortunately, I only converted full_proxy_open() which is used for the new full_proxy_open_regular() and full_proxy_open_short(), but forgot about the call in open_proxy_open(), used for debugfs_create_file_unsafe(). Fix that, it never has short fops. Fixes: f8f25893a477 ("fs: debugfs: differentiate short fops with proxy ops") Reported-by: Suresh Kumar Kurmi Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202501101055.bb8bf3e7-lkp@intel.com Reported-by: Venkat Rao Bagalkote Signed-off-by: Johannes Berg Link: https://lore.kernel.org/r/20250110085826.cd74f3b7a36b.I430c79c82ec3f954c2ff9665753bf6ac9e63eef8@changeid Signed-off-by: Greg Kroah-Hartman

debugfs: fix missing mutex_destroy() in short_fops case

2025-01-07T15:20:11Z

we need that in ->real_fops == NULL, ->short_fops != NULL case Fixes: 8dc6d81c6b2a "debugfs: add small file operations for most files" Signed-off-by: Al Viro Link: https://lore.kernel.org/r/20241229081223.3193228-1-viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman