These three function are now only used in namei.c, so they don't need to be exported. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20260224222542.3458677-16-neilb@ownmail.net Signed-off-by: Christian Brauner <brauner@kernel.org>
lookup_one_qstr_excl() is no longer used outside of namei.c, so make it static. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20260224222542.3458677-9-neilb@ownmail.net Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull directory locking updates from Christian Brauner: "This contains the work to add centralized APIs for directory locking operations. This series is part of a larger effort to change directory operation locking to allow multiple concurrent operations in a directory. The ultimate goal is to lock the target dentry(s) rather than the whole parent directory. To help with changing the locking protocol, this series centralizes locking and lookup in new helper functions. The helpers establish a pattern where it is the dentry that is being locked and unlocked (currently the lock is held on dentry->d_parent->d_inode, but that can change in the future). This also changes vfs_mkdir() to unlock the parent on failure, as well as dput()ing the dentry. This allows end_creating() to only require the target dentry (which may be IS_ERR() after vfs_mkdir()), not the parent" * tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: nfsd: fix end_creating() conversion VFS: introduce end_creating_keep() VFS: change vfs_mkdir() to unlock on failure. ecryptfs: use new start_creating/start_removing APIs Add start_renaming_two_dentries() VFS/ovl/smb: introduce start_renaming_dentry() VFS/nfsd/ovl: introduce start_renaming() and end_renaming() VFS: add start_creating_killable() and start_removing_killable() VFS: introduce start_removing_dentry() smb/server: use end_removing_noperm for for target of smb2_create_link() VFS: introduce start_creating_noperm() and start_removing_noperm() VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing() VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating() VFS: tidy up do_unlinkat() VFS: introduce start_dirop() and end_dirop() debugfs: rename end_creating() to debugfs_end_creating()
Occasionally the caller of end_creating() wants to keep using the dentry. Rather then requiring them to dget() the dentry (when not an error) before calling end_creating(), provide end_creating_keep() which does this. cachefiles and overlayfs make use of this. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-16-neilb@ownmail.net Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
vfs_mkdir() already drops the reference to the dentry on failure but it leaves the parent locked. This complicates end_creating() which needs to unlock the parent even though the dentry is no longer available. If we change vfs_mkdir() to unlock on failure as well as releasing the dentry, we can remove the "parent" arg from end_creating() and simplify the rules for calling it. Note that cachefiles_get_directory() can choose to substitute an error instead of actually calling vfs_mkdir(), for fault injection. In that case it needs to call end_creating(), just as vfs_mkdir() now does on error. ovl_create_real() will now unlock on error. So the conditional end_creating() after the call is removed, and end_creating() is called internally on error. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-15-neilb@ownmail.net Signed-off-by: Christian Brauner <brauner@kernel.org>
This requires the addition of start_creating_dentry() which is given the dentry which has already been found, and asks for it to be locked and its parent validated. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-14-neilb@ownmail.net Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
A few callers want to lock for a rename and already have both dentries. Also debugfs does want to perform a lookup but doesn't want permission checking, so start_renaming_dentry() cannot be used. This patch introduces start_renaming_two_dentries() which is given both dentries. debugfs performs one lookup itself. As it will only continue with a negative dentry and as those cannot be renamed or unlinked, it is safe to do the lookup before getting the rename locks. overlayfs uses start_renaming_two_dentries() in three places and selinux uses it twice in sel_make_policy_nodes(). In sel_make_policy_nodes() we now lock for rename twice instead of just once so the combined operation is no longer atomic w.r.t the parent directory locks. As selinux_state.policy_mutex is held across the whole operation this does not open up any interesting races. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-13-neilb@ownmail.net Signed-off-by: Christian Brauner <brauner@kernel.org>
Several callers perform a rename on a dentry they already have, and only require lookup for the target name. This includes smb/server and a few different places in overlayfs. start_renaming_dentry() performs the required lookup and takes the required lock using lock_rename_child() It is used in three places in overlayfs and in ksmbd_vfs_rename(). In the ksmbd case, the parent of the source is not important - the source must be renamed from wherever it is. So start_renaming_dentry() allows rd->old_parent to be NULL and only checks it if it is non-NULL. On success rd->old_parent will be the parent of old_dentry with an extra reference taken. Other start_renaming function also now take the extra reference and end_renaming() now drops this reference as well. ovl_lookup_temp(), ovl_parent_lock(), and ovl_parent_unlock() are all removed as they are no longer needed. OVL_TEMPNAME_SIZE and ovl_tempname() are now declared in overlayfs.h so that ovl_check_rename_whiteout() can access them. ovl_copy_up_workdir() now always cleans up on error. Reviewed-by: Namjae Jeon <linkinjeon@kernel.org> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-12-neilb@ownmail.net Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
start_renaming() combines name lookup and locking to prepare for rename. It is used when two names need to be looked up as in nfsd and overlayfs - cases where one or both dentries are already available will be handled separately. __start_renaming() avoids the inode_permission check and hash calculation and is suitable after filename_parentat() in do_renameat2(). It subsumes quite a bit of code from that function. start_renaming() does calculate the hash and check X permission and is suitable elsewhere: - nfsd_rename() - ovl_rename() In ovl, ovl_do_rename_rd() is factored out of ovl_do_rename(), which itself will be gone by the end of the series. Acked-by: Chuck Lever <chuck.lever@oracle.com> (for nfsd parts) Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: NeilBrown <neil@brown.name> -- Changes since v3: - added missig dput() in ovl_rename when "whiteout" is not-NULL. Changes since v2: - in __start_renaming() some label have been renamed, and err is always set before a "goto out_foo" rather than passing the error in a dentry*. - ovl_do_rename() changed to call the new ovl_do_rename_rd() rather than keeping duplicate code - code around ovl_cleanup() call in ovl_rename() restructured. Link: https://patch.msgid.link/20251113002050.676694-11-neilb@ownmail.net Tested-by: syzbot@syzkaller.appspotmail.com Acked-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
These are similar to start_creating() and start_removing(), but allow a fatal signal to abort waiting for the lock. They are used in btrfs for subvol creation and removal. btrfs_may_create() no longer needs IS_DEADDIR() and start_creating_killable() includes that check. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neil@brown.name> Link: https://patch.msgid.link/20251113002050.676694-10-neilb@ownmail.net Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>