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Date: Sat, 13 Feb 2010 20:31:17 +0100
From: Joris Dolderer <vorstadtkind@...glemail.com>
To: linux-kernel@...r.kernel.org
Cc: Randy Dunlap <rdunlap@...otime.net>
Subject: Re: [PATCH 1/3] fsnotify: tree-watching support
Shall I, now, resubmit immediately or wait for other reviews?
On Sat, 13 Feb 2010 11:12:15 -0800
Randy Dunlap <rdunlap@...otime.net> wrote:
> On 02/13/10 01:05, Joris Dolderer wrote:
> > Add tree-watching support to fsnotify.
> > Hope mail works now...
>
> Yes, much better, thanks.
>
> The following review just concerns documentation...
>
> > Signed-off-by: Joris Dolderer <vorstadtkind@...glemail.com>
> > ---
> > fs/debugfs/inode.c | 8 -
> > fs/namei.c | 8 -
> > fs/notify/fsnotify.c | 188 +++++++++++++++++++++++------
> > fs/notify/fsnotify.h | 1
> > fs/notify/inode_mark.c | 46 ++++++-
> > include/linux/dcache.h | 3
> > include/linux/fsnotify.h | 55 +++++---
> > include/linux/fsnotify_backend.h | 51 +++++--
> > 8 files changed, 279 insertions(+), 81 deletions(-)
>
>
> > diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> > index 037e878..17cd902 100644
> > --- a/fs/notify/fsnotify.c
> > +++ b/fs/notify/fsnotify.c
>
> [snip]
>
> > +/* Notify this dentry's ancestors about a child's events. */
> > +void __fsnotify_ancestors(struct dentry *dentry, __u32 mask)
> > +{
> > + if (dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED) {
> > + struct dentry *parent;
> > + struct inode *p_inode;
> > + bool should_update_children = false;
> > + bool send = false;
> > +
> > + spin_lock(&dentry->d_lock);
> > +
> > + parent = dentry->d_parent;
> > + p_inode = parent->d_inode;
> >
> > - if (fsnotify_inode_watches_children(p_inode)) {
> > - if (p_inode->i_fsnotify_mask & mask) {
> > + if (fsnotify_inode_watches_children(p_inode)) {
> > + if (p_inode->i_fsnotify_mask & mask) {
> > + dget(parent);
> > + send = true;
> > + }
> > + } else {
> > + /*
> > + * The parent doesn't care about events on it's children but
>
> its
> (yes, it's just moved, but please correct it)
> ("it's" means "it is", not possessive)
>
> > + * at least one child thought it did. We need to run all the
> > + * children and update their d_flags to let them know p_inode
> > + * doesn't care about them any more.
> > + */
> > dget(parent);
> > - send = true;
> > + should_update_children = true;
> > }
>
> [snip]
>
> > +}
> > +EXPORT_SYMBOL_GPL(__fsnotify_ancestors);
> > +
> > +/*
> > + * notify tree-watching ancestors
> > + * @dentry: The dentry the walkup should start with
> > + * @file_name: The string that should be appended to this dentries' path
> > + * @file_len: The length of this string
> > + */
>
> Please use kernel-doc notation for this and other exported symbols.
> See Documentation/kernel-doc-nano-HOWTO.txt for details, or ask me if you
> have questions about it.
>
> E.g.:
>
> /**
> * fsnotify_far_ancestors - notify tree-watching ancestors
> * @dentry: The dentry the walkup should start with
> * @file_name: The string that should be appended to this dentries' path
> * @file_len: The length of this string
> * @mask: <description>
> */
>
>
> > +void fsnotify_far_ancestors(struct dentry *dentry, const unsigned char *file_name, int file_len, __u32 mask)
> > +{
> ...
>
> > }
> > -EXPORT_SYMBOL_GPL(__fsnotify_parent);
> > +EXPORT_SYMBOL_GPL(fsnotify_far_ancestors);
> >
> > /*
> > * This is the main call to fsnotify. The VFS calls into hook specific functions
>
> > diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
> > index 3165d85..67ad9cb 100644
> > --- a/fs/notify/inode_mark.c
> > +++ b/fs/notify/inode_mark.c
> > @@ -195,14 +216,16 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry)
> >
> > /*
> > * __fsnotify_update_child_dentry_flags(inode);
> > + * or __fsnotify_update_descents;
> > *
> > * I really want to call that, but we can't, we have no idea if the inode
> > * still exists the second we drop the entry->lock.
> > *
> > * The next time an event arrive to this inode from one of it's children
>
> arrives its
>
> > - * __fsnotify_parent will see that the inode doesn't care about it's
> > - * children and will update all of these flags then. So really this
> > - * is just a lazy update (and could be a perf win...)
> > + * __fsnotify_ancestors resp. fsnotify_far_ancestors will see that the
>
> What is "resp." ?
>
> > + * inode doesn't care about it's children and will update all of these
>
> its
>
> > + * flags then. So really this is just a lazy update (and could be a
> > + * perf win...)
> > */
>
> > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> > index 4d6f47b..1bea473 100644
> > --- a/include/linux/fsnotify_backend.h
> > +++ b/include/linux/fsnotify_backend.h
>
> [snip]
>
> > -static inline int fsnotify_inode_watches_children(struct inode *inode)
> > +static inline bool fsnotify_inode_watches_something(struct inode *inode, u32 what)
> > {
> > - /* FS_EVENT_ON_CHILD is set if the inode may care */
> > - if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
> > + /* what is set if the inode may care */
> > + if (!(inode->i_fsnotify_mask & what))
> > return 0;
>
> return false;
>
> > /* this inode might care about child events, does it care about the
> > * specific set of events that can happen on a child? */
> > return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
> > }
>
>
> --
> ~Randy
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