On Mon, Jun 17, 2024 at 12:37 PM Jan Kara <jack@xxxxxxx> wrote: > > On Sat 15-06-24 07:35:42, Christian Brauner wrote: > > On Wed, 12 Jun 2024 17:09:55 +1000, NeilBrown wrote: > > > When a file is opened and created with open(..., O_CREAT) we get > > > both the CREATE and OPEN fsnotify events and would expect them in that > > > order. For most filesystems we get them in that order because > > > open_last_lookups() calls fsnofify_create() and then do_open() (from > > > path_openat()) calls vfs_open()->do_dentry_open() which calls > > > fsnotify_open(). > > > > > > [...] > > > > Applied to the vfs.fixes branch of the vfs/vfs.git tree. > > Patches in the vfs.fixes branch should appear in linux-next soon. > > > > Please report any outstanding bugs that were missed during review in a > > new review to the original patch series allowing us to drop it. > > > > It's encouraged to provide Acked-bys and Reviewed-bys even though the > > patch has now been applied. If possible patch trailers will be updated. > > > > Note that commit hashes shown below are subject to change due to rebase, > > trailer updates or similar. If in doubt, please check the listed branch. > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git > > branch: vfs.fixes > > > > [1/1] VFS: generate FS_CREATE before FS_OPEN when ->atomic_open used. > > https://git.kernel.org/vfs/vfs/c/7536b2f06724 > > I have reviewed the patch you've committed since I wasn't quite sure which > changes you're going to apply after your discussion with Amir. And I have > two comments: > > @@ -1085,8 +1080,17 @@ EXPORT_SYMBOL(file_path); > */ > int vfs_open(const struct path *path, struct file *file) > { > + int ret; > + > file->f_path = *path; > - return do_dentry_open(file, NULL); > + ret = do_dentry_open(file, NULL); > + if (!ret) > + /* > + * Once we return a file with FMODE_OPENED, __fput() will call > + * fsnotify_close(), so we need fsnotify_open() here for symmetry. > + */ > + fsnotify_open(file); Please add { } around multi line indented text. > + return ret; > } > > AFAICT this will have a side-effect that now fsnotify_open() will be > generated even for O_PATH open. It is true that fsnotify_close() is getting > generated for them already and we should strive for symmetry. Conceptually > it doesn't make sense to me to generate fsnotify events for O_PATH > opens/closes but maybe I miss something. Amir, any opinion here? Good catch! I agree that we do not need OPEN nor CLOSE events for O_PATH. I suggest to solve it with: @@ -915,7 +929,7 @@ static int do_dentry_open(struct file *f, f->f_sb_err = file_sample_sb_err(f); if (unlikely(f->f_flags & O_PATH)) { - f->f_mode = FMODE_PATH | FMODE_OPENED; + f->f_mode = FMODE_PATH | FMODE_OPENED | __FMODE_NONOTIFY; f->f_op = &empty_fops; return 0; } > > @@ -3612,6 +3612,9 @@ static int do_open(struct nameidata *nd, > int acc_mode; > int error; > > + if (file->f_mode & FMODE_OPENED) > + fsnotify_open(file); > + > if (!(file->f_mode & (FMODE_OPENED | FMODE_CREATED))) { > error = complete_walk(nd); > if (error) > > Frankly, this works but looks as an odd place to put this notification to. > Why not just placing it just next to where fsnotify_create() is generated > in open_last_lookups()? Like: > > if (open_flag & O_CREAT) > inode_lock(dir->d_inode); > else > inode_lock_shared(dir->d_inode); > dentry = lookup_open(nd, file, op, got_write); > - if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED)) > - fsnotify_create(dir->d_inode, dentry); > + if (!IS_ERR(dentry)) { > + if (file->f_mode & FMODE_CREATED) > + fsnotify_create(dir->d_inode, dentry); > + if (file->f_mode & FMODE_OPENED) > + fsnotify_open(file); > + } > if (open_flag & O_CREAT) > inode_unlock(dir->d_inode); > else > inode_unlock_shared(dir->d_inode); > > That looks like a place where it is much more obvious this is for > atomic_open() handling? Now I admit I'm not really closely familiar with > the atomic_open() paths so maybe I miss something and do_open() is better. It looks nice, but I think it is missing the fast lookup case without O_CREAT (i.e. goto finish_lookup). Thanks, Amir.
