Re: [RESEND PATCH] inotify: update documentation to reflect code changes

[Zhang Zhen <zhenzhang.zhang@huawei.com>]

On 2015/1/28 5:52, Heinrich Schuchardt wrote:
> 
> Sections (i) and (ii) of Documentation/filesystems/inotify.txt have been
> superseded by the inotify.7, inotify_init.2, inotify_rm_watch.2, and
> inotify_add_watch.2 man-pages which are more detailed. In sections (i)
> and (ii) the inotify_init1 system call is missing.
> 
> Zhang suggests to drop sections (iii) and (iv) as they are obsolete
> since 2010.
> 
> Shouldn't we drop the whole file?
> 
Yeah, i agree.
Thanks!

> Best regards
> 
> Heinrich Schuchardt
> 
> On 27.01.2015 13:45, Zhang Zhen wrote:
>> The inotify kernel interface was removed by Eric Paris
>> in this commit: 2dfc1ca inotify: remove inotify in
>> kernel interface.
>>
>> Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
>> ---
>>  Documentation/filesystems/inotify.txt | 120 +---------------------------------
>>  1 file changed, 2 insertions(+), 118 deletions(-)
>>
>> diff --git a/Documentation/filesystems/inotify.txt b/Documentation/filesystems/inotify.txt
>> index cfd0271..9b74b45 100644
>> --- a/Documentation/filesystems/inotify.txt
>> +++ b/Documentation/filesystems/inotify.txt
>> @@ -69,123 +69,7 @@ Prototypes:
>>  	int inotify_rm_watch (int fd, __u32 mask);
>>
>>
>> -(iii) Kernel Interface
>> -
>> -Inotify's kernel API consists a set of functions for managing watches and an
>> -event callback.
>> -
>> -To use the kernel API, you must first initialize an inotify instance with a set
>> -of inotify_operations.  You are given an opaque inotify_handle, which you use
>> -for any further calls to inotify.
>> -
>> -    struct inotify_handle *ih = inotify_init(my_event_handler);
>> -
>> -You must provide a function for processing events and a function for destroying
>> -the inotify watch.
>> -
>> -    void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
>> -    	              u32 cookie, const char *name, struct inode *inode)
>> -
>> -	watch - the pointer to the inotify_watch that triggered this call
>> -	wd - the watch descriptor
>> -	mask - describes the event that occurred
>> -	cookie - an identifier for synchronizing events
>> -	name - the dentry name for affected files in a directory-based event
>> -	inode - the affected inode in a directory-based event
>> -
>> -    void destroy_watch(struct inotify_watch *watch)
>> -
>> -You may add watches by providing a pre-allocated and initialized inotify_watch
>> -structure and specifying the inode to watch along with an inotify event mask.
>> -You must pin the inode during the call.  You will likely wish to embed the
>> -inotify_watch structure in a structure of your own which contains other
>> -information about the watch.  Once you add an inotify watch, it is immediately
>> -subject to removal depending on filesystem events.  You must grab a reference if
>> -you depend on the watch hanging around after the call.
>> -
>> -    inotify_init_watch(&my_watch->iwatch);
>> -    inotify_get_watch(&my_watch->iwatch);	// optional
>> -    s32 wd = inotify_add_watch(ih, &my_watch->iwatch, inode, mask);
>> -    inotify_put_watch(&my_watch->iwatch);	// optional
>> -
>> -You may use the watch descriptor (wd) or the address of the inotify_watch for
>> -other inotify operations.  You must not directly read or manipulate data in the
>> -inotify_watch.  Additionally, you must not call inotify_add_watch() more than
>> -once for a given inotify_watch structure, unless you have first called either
>> -inotify_rm_watch() or inotify_rm_wd().
>> -
>> -To determine if you have already registered a watch for a given inode, you may
>> -call inotify_find_watch(), which gives you both the wd and the watch pointer for
>> -the inotify_watch, or an error if the watch does not exist.
>> -
>> -    wd = inotify_find_watch(ih, inode, &watchp);
>> -
>> -You may use container_of() on the watch pointer to access your own data
>> -associated with a given watch.  When an existing watch is found,
>> -inotify_find_watch() bumps the refcount before releasing its locks.  You must
>> -put that reference with:
>> -
>> -    put_inotify_watch(watchp);
>> -
>> -Call inotify_find_update_watch() to update the event mask for an existing watch.
>> -inotify_find_update_watch() returns the wd of the updated watch, or an error if
>> -the watch does not exist.
>> -
>> -    wd = inotify_find_update_watch(ih, inode, mask);
>> -
>> -An existing watch may be removed by calling either inotify_rm_watch() or
>> -inotify_rm_wd().
>> -
>> -    int ret = inotify_rm_watch(ih, &my_watch->iwatch);
>> -    int ret = inotify_rm_wd(ih, wd);
>> -
>> -A watch may be removed while executing your event handler with the following:
>> -
>> -    inotify_remove_watch_locked(ih, iwatch);
>> -
>> -Call inotify_destroy() to remove all watches from your inotify instance and
>> -release it.  If there are no outstanding references, inotify_destroy() will call
>> -your destroy_watch op for each watch.
>> -
>> -    inotify_destroy(ih);
>> -
>> -When inotify removes a watch, it sends an IN_IGNORED event to your callback.
>> -You may use this event as an indication to free the watch memory.  Note that
>> -inotify may remove a watch due to filesystem events, as well as by your request.
>> -If you use IN_ONESHOT, inotify will remove the watch after the first event, at
>> -which point you may call the final inotify_put_watch.
>> -
>> -(iv) Kernel Interface Prototypes
>> -
>> -	struct inotify_handle *inotify_init(struct inotify_operations *ops);
>> -
>> -	inotify_init_watch(struct inotify_watch *watch);
>> -
>> -	s32 inotify_add_watch(struct inotify_handle *ih,
>> -		              struct inotify_watch *watch,
>> -			      struct inode *inode, u32 mask);
>> -
>> -	s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
>> -			       struct inotify_watch **watchp);
>> -
>> -	s32 inotify_find_update_watch(struct inotify_handle *ih,
>> -				      struct inode *inode, u32 mask);
>> -
>> -	int inotify_rm_wd(struct inotify_handle *ih, u32 wd);
>> -
>> -	int inotify_rm_watch(struct inotify_handle *ih,
>> -			     struct inotify_watch *watch);
>> -
>> -	void inotify_remove_watch_locked(struct inotify_handle *ih,
>> -					 struct inotify_watch *watch);
>> -
>> -	void inotify_destroy(struct inotify_handle *ih);
>> -
>> -	void get_inotify_watch(struct inotify_watch *watch);
>> -	void put_inotify_watch(struct inotify_watch *watch);
>> -
>> -
>> -(v) Internal Kernel Implementation
>> +(iii) Internal Kernel Implementation
>>
>>  Each inotify instance is represented by an inotify_handle structure.
>>  Inotify's userspace consumers also have an inotify_device which is
>> @@ -198,7 +82,7 @@ See fs/notify/inotify/inotify_fsnotify.c and fs/notify/inotify/inotify_user.c
>>  for the locking and lifetime rules.
>>
>>
>> -(vi) Rationale
>> +(iv) Rationale
>>
>>  Q: What is the design decision behind not tying the watch to the open fd of
>>     the watched object?
>>
> 
> 
> .
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