28 Jun, 2018
1 commit
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The flag IN_MASK_CREATE is introduced as a flag for inotiy_add_watch()
which prevents inotify from modifying any existing watches when invoked.
If the pathname specified in the call has a watched inode associated
with it and IN_MASK_CREATE is specified, fail with an errno of EEXIST.Use of IN_MASK_CREATE with IN_MASK_ADD is reserved for future use and
will return EINVAL.RATIONALE
In the current implementation, there is no way to prevent
inotify_add_watch() from modifying existing watch descriptors. Even if
the caller keeps a record of all watch descriptors collected, this is
only sufficient to detect that an existing watch descriptor may have
been modified.The assumption that a particular path will map to the same inode over
multiple calls to inotify_add_watch() cannot be made as files can be
renamed or deleted. It is also not possible to assume that two distinct
paths do no map to the same inode, due to hard-links or a dereferenced
symbolic link. Further uses of inotify_add_watch() to revert the change
may cause other watch descriptors to be modified or created, merely
compunding the problem. There is currently no system call such as
inotify_modify_watch() to explicity modify a watch descriptor, which
would be able to revert unwanted changes. Thus the caller cannot
guarantee to be able to revert any changes to existing watch decriptors.Additionally the caller cannot assume that the events that are
associated with a watch descriptor are within the set requested, as any
future calls to inotify_add_watch() may unintentionally modify a watch
descriptor's mask. Thus it cannot currently be guaranteed that a watch
descriptor will only generate events which have been requested. The
program must filter events which come through its watch descriptor to
within its expected range.Reviewed-by: Amir Goldstein
Signed-off-by: Henry Wilson
Signed-off-by: Jan Kara
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
13 Oct, 2012
1 commit
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Signed-off-by: David Howells
Acked-by: Arnd Bergmann
Acked-by: Thomas Gleixner
Acked-by: Michael Kerrisk
Acked-by: Paul E. McKenney
Acked-by: Dave Jones
28 Jul, 2010
4 commits
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inotify uses bits called IN_* and fsnotify uses bits called FS_*. These
need to line up. This patch adds build time checks to make sure noone can
change these bits so they are not the same.Signed-off-by: Eric Paris
-
An inotify watch on a directory will send events for children even if those
children have been unlinked. This patch add a new inotify flag IN_EXCL_UNLINK
which allows a watch to specificy they don't care about unlinked children.
This should fix performance problems seen by tasks which add a watch to
/tmp and then are overrun with events when other processes are reading and
writing to unlinked files they created in /tmp.https://bugzilla.kernel.org/show_bug.cgi?id=16296
Requested-by: Matthias Clasen
Signed-off-by: Eric Paris -
Extern declarations in sysctl.c should be move to their own head file, and
then include them in relavant .c files.Move inotify_table extern declaration to linux/inotify.h
Signed-off-by: Dave Young
Signed-off-by: Andrew Morton
Signed-off-by: Eric Paris -
nothing uses inotify in the kernel, drop it!
Signed-off-by: Eric Paris
16 Nov, 2008
1 commit
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Inotify watch removals suck violently.
To kick the watch out we need (in this order) inode->inotify_mutex and
ih->mutex. That's fine if we have a hold on inode; however, for all
other cases we need to make damn sure we don't race with umount. We can
*NOT* just grab a reference to a watch - inotify_unmount_inodes() will
happily sail past it and we'll end with reference to inode potentially
outliving its superblock.Ideally we just want to grab an active reference to superblock if we
can; that will make sure we won't go into inotify_umount_inodes() until
we are done. Cleanup is just deactivate_super().However, that leaves a messy case - what if we *are* racing with
umount() and active references to superblock can't be acquired anymore?
We can bump ->s_count, grab ->s_umount, which will almost certainly wait
until the superblock is shut down and the watch in question is pining
for fjords. That's fine, but there is a problem - we might have hit the
window between ->s_active getting to 0 / ->s_count - below S_BIAS (i.e.
the moment when superblock is past the point of no return and is heading
for shutdown) and the moment when deactivate_super() acquires
->s_umount.We could just do drop_super() yield() and retry, but that's rather
antisocial and this stuff is luser-triggerable. OTOH, having grabbed
->s_umount and having found that we'd got there first (i.e. that
->s_root is non-NULL) we know that we won't race with
inotify_umount_inodes().So we could grab a reference to watch and do the rest as above, just
with drop_super() instead of deactivate_super(), right? Wrong. We had
to drop ih->mutex before we could grab ->s_umount. So the watch
could've been gone already.That still can be dealt with - we need to save watch->wd, do idr_find()
and compare its result with our pointer. If they match, we either have
the damn thing still alive or we'd lost not one but two races at once,
the watch had been killed and a new one got created with the same ->wd
at the same address. That couldn't have happened in inotify_destroy(),
but inotify_rm_wd() could run into that. Still, "new one got created"
is not a problem - we have every right to kill it or leave it alone,
whatever's more convenient.So we can use idr_find(...) == watch && watch->inode->i_sb == sb as
"grab it and kill it" check. If it's been our original watch, we are
fine, if it's a newcomer - nevermind, just pretend that we'd won the
race and kill the fscker anyway; we are safe since we know that its
superblock won't be going away.And yes, this is far beyond mere "not very pretty"; so's the entire
concept of inotify to start with.Signed-off-by: Al Viro
Acked-by: Greg KH
Signed-off-by: Linus Torvalds
25 Jul, 2008
2 commits
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This patch adds non-blocking support for inotify_init1. The
additional changes needed are minimal.The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include
#include
#include
#include#ifndef __NR_inotify_init1
# ifdef __x86_64__
# define __NR_inotify_init1 294
# elif defined __i386__
# define __NR_inotify_init1 332
# else
# error "need __NR_inotify_init1"
# endif
#endif#define IN_NONBLOCK O_NONBLOCK
int
main (void)
{
int fd = syscall (__NR_inotify_init1, 0);
if (fd == -1)
{
puts ("inotify_init1(0) failed");
return 1;
}
int fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if (fl & O_NONBLOCK)
{
puts ("inotify_init1(0) set non-blocking mode");
return 1;
}
close (fd);fd = syscall (__NR_inotify_init1, IN_NONBLOCK);
if (fd == -1)
{
puts ("inotify_init1(IN_NONBLOCK) failed");
return 1;
}
fl = fcntl (fd, F_GETFL);
if (fl == -1)
{
puts ("fcntl failed");
return 1;
}
if ((fl & O_NONBLOCK) == 0)
{
puts ("inotify_init1(IN_NONBLOCK) set non-blocking mode");
return 1;
}
close (fd);puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Signed-off-by: Ulrich Drepper
Acked-by: Davide Libenzi
Cc: Michael Kerrisk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch introduces the new syscall inotify_init1 (note: the 1 stands for
the one parameter the syscall takes, as opposed to no parameter before). The
values accepted for this parameter are function-specific and defined in the
inotify.h header. Here the values must match the O_* flags, though. In this
patch CLOEXEC support is introduced.The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include
#include
#include
#include#ifndef __NR_inotify_init1
# ifdef __x86_64__
# define __NR_inotify_init1 294
# elif defined __i386__
# define __NR_inotify_init1 332
# else
# error "need __NR_inotify_init1"
# endif
#endif#define IN_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd;
fd = syscall (__NR_inotify_init1, 0);
if (fd == -1)
{
puts ("inotify_init1(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("inotify_init1(0) set close-on-exit");
return 1;
}
close (fd);fd = syscall (__NR_inotify_init1, IN_CLOEXEC);
if (fd == -1)
{
puts ("inotify_init1(IN_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("inotify_init1(O_CLOEXEC) does not set close-on-exit");
return 1;
}
close (fd);puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[akpm@linux-foundation.org: add sys_ni stub]
Signed-off-by: Ulrich Drepper
Acked-by: Davide Libenzi
Cc: Michael Kerrisk
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 Oct, 2007
2 commits
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Kicks the watch out without dropping it. Called under ->inotify_mutex
Signed-off-by: Al Viro
-
Signed-off-by: Al Viro
20 Jun, 2006
5 commits
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Allow callers to remove watches from their event handler via
inotify_remove_watch_locked(). This functionality can be used to
achieve IN_ONESHOT-like functionality for a subset of events in the
mask.Signed-off-by: Amy Griffis
Acked-by: Robert Love
Acked-by: John McCutchan
Signed-off-by: Al Viro -
Add inotify_init_watch() so caller can use inotify_watch refcounts
before calling inotify_add_watch().Add inotify_find_watch() to find an existing watch for an (ih,inode)
pair. This is similar to inotify_find_update_watch(), but does not
update the watch's mask if one is found.Add inotify_rm_watch() to remove a watch via the watch pointer instead
of the watch descriptor.Signed-off-by: Amy Griffis
Acked-by: Robert Love
Acked-by: John McCutchan
Signed-off-by: Al Viro -
When an inotify event includes a dentry name, also include the inode
associated with that name.Signed-off-by: Amy Griffis
Acked-by: Robert Love
Acked-by: John McCutchan
Signed-off-by: Al Viro -
The following series of patches introduces a kernel API for inotify,
making it possible for kernel modules to benefit from inotify's
mechanism for watching inodes. With these patches, inotify will
maintain for each caller a list of watches (via an embedded struct
inotify_watch), where each inotify_watch is associated with a
corresponding struct inode. The caller registers an event handler and
specifies for which filesystem events their event handler should be
called per inotify_watch.Signed-off-by: Amy Griffis
Acked-by: Robert Love
Acked-by: John McCutchan
Signed-off-by: Al Viro -
Signed-off-by: Al Viro
26 Mar, 2006
1 commit
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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
Cc: Robert Love
Cc: John McCutchan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Dec, 2005
1 commit
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The below patch lets userspace have more control over the inodes that
inotify will watch. It introduces two new flags.IN_ONLYDIR -- only watch the inode if it is a directory.
This is needed to avoid the race that can occur when we want to be
sure that we are watching a directory.IN_DONT_FOLLOW -- don't follow a symlink. In combination
with IN_ONLYDIR we can make sure that we don't watch the target of
symlinks.The issues the flags fix came up when writing the gnome-vfs inotify
backend. Default behaviour is unchanged.Signed-off-by: John McCutchan
Acked-by: Robert Love
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Sep, 2005
1 commit
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People have run into a problem when they do this:
watch (file1, all_events);
watch (file2, some_events);if file2 is a hard link to file1, some events will be missed because by
default we replace the mask. The patch below adds a flag IN_MASK_ADD which
will cause inotify to add to the existing mask if present.Signed-off-by: John McCutchan
Signed-off-by: Robert Love
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Aug, 2005
1 commit
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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/mtabapp1 still thinks it's watching /etc/mtab but it's actually watching
/etc/mtab~.Signed-off-by: John McCutchan
Signed-off-by: Robert Love
Signed-off-by: Linus Torvalds
13 Jul, 2005
1 commit
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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
Cc: John McCutchan
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
