fsnotify tells its listeners explicitly when an event happened on the given
inode verses on the child of the given inode. (see __fsnotify_parent)
However, the semantics of fsnotify_move() are such that we deliver events
directly to the two parent directories in question (old_dir and new_dir)
directly without using the __fsnotify_parent() call. fsnotify should be
adding FS_EVENT_ON_CHILD for the notifications to these parents.
Signed-off-by: Eric Paris <eparis@redhat.com>
As part of the standard inotify events it includes a correlation cookie
between two dentry move operations. This patch includes the same behaviour
in fsnotify events. It is needed so that inotify userspace can be
implemented on top of fsnotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
When inotify wants to send events to a directory about a child it includes
the name of the original file. This patch collects that filename and makes
it available for notification.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Reimplement dnotify using fsnotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
inotify and dnotify both use a similar parent notification mechanism. We
add a generic parent notification mechanism to fsnotify for both of these
to use. This new machanism also adds the dentry flag optimization which
exists for inotify to dnotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
This patch creates a way for fsnotify groups to attach marks to inodes.
These marks have little meaning to the generic fsnotify infrastructure
and thus their meaning should be interpreted by the group that attached
them to the inode's list.
dnotify and inotify will make use of these markings to indicate which
inodes are of interest to their respective groups. But this implementation
has the useful property that in the future other listeners could actually
use the marks for the exact opposite reason, aka to indicate which inodes
it had NO interest in.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
fsnotify is a backend for filesystem notification. fsnotify does
not provide any userspace interface but does provide the basis
needed for other notification schemes such as dnotify. fsnotify
can be extended to be the backend for inotify or the upcoming
fanotify. fsnotify provides a mechanism for "groups" to register for
some set of filesystem events and to then deliver those events to
those groups for processing.
fsnotify has a number of benefits, the first being actually shrinking the size
of an inode. Before fsnotify to support both dnotify and inotify an inode had
unsigned long i_dnotify_mask; /* Directory notify events */
struct dnotify_struct *i_dnotify; /* for directory notifications */
struct list_head inotify_watches; /* watches on this inode */
struct mutex inotify_mutex; /* protects the watches list
But with fsnotify this same functionallity (and more) is done with just
__u32 i_fsnotify_mask; /* all events for this inode */
struct hlist_head i_fsnotify_mark_entries; /* marks on this inode */
That's right, inotify, dnotify, and fanotify all in 64 bits. We used that
much space just in inotify_watches alone, before this patch set.
fsnotify object lifetime and locking is MUCH better than what we have today.
inotify locking is incredibly complex. See 8f7b0ba1c8 as an example of
what's been busted since inception. inotify needs to know internal semantics
of superblock destruction and unmounting to function. The inode pinning and
vfs contortions are horrible.
no fsnotify implementers do allocation under locks. This means things like
f04b30de3 which (due to an overabundance of caution) changes GFP_KERNEL to
GFP_NOFS can be reverted. There are no longer any allocation rules when using
or implementing your own fsnotify listener.
fsnotify paves the way for fanotify. In brief fanotify is a notification
mechanism that delivers the lisener both an 'event' and an open file descriptor
to the object in question. This means that fanotify is pathname agnostic.
Some on lkml may not care for the original companies or users that pushed for
TALPA, but fanotify was designed with flexibility and input for other users in
mind. The readahead group expressed interest in fanotify as it could be used
to profile disk access on boot without breaking the audit system. The desktop
search groups have also expressed interest in fanotify as it solves a number
of the race conditions and problems present with managing inotify when more
than a limited number of specific files are of interest. fanotify can provide
for a userspace access control system which makes it a clean interface for AV
vendors to hook without trying to do binary patching on the syscall table,
LSM, and everywhere else they do their things today. With this patch series
fanotify can be implemented in less than 1200 lines of easy to review code.
Almost all of which is the socket based user interface.
This patch series builds fsnotify to the point that it can implement
dnotify and inotify_user. Patches exist and will be sent soon after
acceptance to finish the in kernel inotify conversion (audit) and implement
fanotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Remove the "#ifdef __KERNEL__" tests from unexported header files in
linux/include whose entire contents are wrapped in that preprocessor
test.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, no notification event has been sent when inode's link count
changed. This is inconvenient for the application in some cases:
Suppose you have the following directory structure
foo/test
bar/
and you watch test. If someone does "mv foo/test bar/", you get event
IN_MOVE_SELF and you know something has happened with the file "test".
However if someone does "ln foo/test bar/test" and "rm foo/test" you get no
inotify event for the file "test" (only directories "foo" and "bar" receive
events).
Furthermore it could be argued that link count belongs to file's metadata and
thus IN_ATTRIB should be sent when it changes.
The following patch implements sending of IN_ATTRIB inotify events when link
count of the inode changes, i.e., when a hardlink to the inode is created or
when it is removed. This event is sent in addition to all the events sent so
far. In particular, when a last link to a file is removed, IN_ATTRIB event is
sent in addition to IN_DELETE_SELF event.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Morten Welinder <mwelinder@gmail.com>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes struct file to use struct path instead of having
independent pointers to struct dentry and struct vfsmount, and converts all
users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}.
Additionally, it adds two #define's to make the transition easier for users of
the f_dentry and f_vfsmnt.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When an object is created via a symlink into an audited directory, audit misses
the event due to not having collected the inode data for the directory. Modify
__audit_inode_child() to copy the parent inode data if a parent wasn't found in
audit_names[].
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When an inotify event includes a dentry name, also include the inode
associated with that name.
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Acked-by: Robert Love <rml@novell.com>
Acked-by: John McCutchan <john@johnmccutchan.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Previous inotify work avoidance is good when inotify is completely unused,
but it breaks down if even a single watch is in place anywhere in the
system. Robin Holt notices that udev is one such culprit - it slows down a
512-thread application on a 512 CPU system from 6 seconds to 22 minutes.
Solve this by adding a flag in the dentry that tells inotify whether or not
its parent inode has a watch on it. Event queueing to parent will skip
taking locks if this flag is cleared. Setting and clearing of this flag on
all child dentries versus event delivery: this is no in terms of race
cases, and that was shown to be equivalent to always performing the check.
The essential behaviour is that activity occuring _after_ a watch has been
added and _before_ it has been removed, will generate events.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch augments the collection of inode info during syscall
processing. It represents part of the functionality that was provided
by the auditfs patch included in RHEL4.
Specifically, it:
- Collects information for target inodes created or removed during
syscalls. Previous code only collects information for the target
inode's parent.
- Adds the audit_inode() hook to syscalls that operate on a file
descriptor (e.g. fchown), enabling audit to do inode filtering for
these calls.
- Modifies filtering code to check audit context for either an inode #
or a parent inode # matching a given rule.
- Modifies logging to provide inode # for both parent and child.
- Protect debug info from NULL audit_names.name.
[AV: folded a later typo fix from the same author]
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The audit hooks (to be added shortly) will want to see dentry->d_inode
too, not just the name.
Signed-off-by: Amy Griffis <amy.griffis@hp.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This adds a MOVE_SELF event to inotify. It is sent whenever the inode
you are watching is moved. We need this event so that we can catch
something like this:
- app1:
watch /etc/mtab
- app2:
cp /etc/mtab /tmp/mtab-work
mv /etc/mtab /etc/mtab~
mv /tmp/mtab-work /etc/mtab
app1 still thinks it's watching /etc/mtab but it's actually watching
/etc/mtab~.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This removes the now unused fsnotify_unlink & fsnotify_rmdir code.
Compile tested.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The patch below unhooks fsnotify from vfs_unlink & vfs_rmdir. It
introduces two new fsnotify calls, that are hooked in at the dcache
level. This not only more closely matches how the VFS layer works, it
also avoids the problem with locking and inode lifetimes.
The two functions are
- fsnotify_nameremove -- called when a directory entry is going away.
It notifies the PARENT of the deletion. This is called from
d_delete().
- inoderemove -- called when the files inode itself is going away. It
notifies the inode that is being deleted. This is called from
dentry_iput().
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This avoids the whole #ifdef mess by just getting a copy of
dentry->d_inode before d_delete is called - that makes the codepaths the
same for the INOTIFY/DNOTIFY cases as for the regular no-notify case.
I've been running this under a Gnome session for the last 10 minutes.
Inotify is being used extensively.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a file is moved over an existing file that you are watching,
inotify won't send you a DELETE_SELF event and it won't unref the inode
until the inotify instance is closed by the application.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This rearranges the event ordering for "open" to be consistent with the
ordering of the other events.
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:
* dnotify requires the opening of one fd per each directory
that you intend to watch. This quickly results in too many
open files and pins removable media, preventing unmount.
* dnotify is directory-based. You only learn about changes to
directories. Sure, a change to a file in a directory affects
the directory, but you are then forced to keep a cache of
stat structures.
* dnotify's interface to user-space is awful. Signals?
inotify provides a more usable, simple, powerful solution to file change
notification:
* inotify's interface is a system call that returns a fd, not SIGIO.
You get a single fd, which is select()-able.
* inotify has an event that says "the filesystem that the item
you were watching is on was unmounted."
* inotify can watch directories or files.
Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.
See Documentation/filesystems/inotify.txt.
Signed-off-by: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Al Viro