* [PATCH AUTOSEL 4.14 47/95] fuse: fix possibly missed wake-up after abort
[not found] <20190507053826.31622-1-sashal@kernel.org>
@ 2019-05-07 5:37 ` Sasha Levin
2019-05-07 5:37 ` [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2019-05-07 5:37 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Miklos Szeredi, Sasha Levin, linux-fsdevel
From: Miklos Szeredi <mszeredi@redhat.com>
[ Upstream commit 2d84a2d19b6150c6dbac1e6ebad9c82e4c123772 ]
In current fuse_drop_waiting() implementation it's possible that
fuse_wait_aborted() will not be woken up in the unlikely case that
fuse_abort_conn() + fuse_wait_aborted() runs in between checking
fc->connected and calling atomic_dec(&fc->num_waiting).
Do the atomic_dec_and_test() unconditionally, which also provides the
necessary barrier against reordering with the fc->connected check.
The explicit smp_mb() in fuse_wait_aborted() is not actually needed, since
the spin_unlock() in fuse_abort_conn() provides the necessary RELEASE
barrier after resetting fc->connected. However, this is not a performance
sensitive path, and adding the explicit barrier makes it easier to
document.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: b8f95e5d13f5 ("fuse: umount should wait for all requests")
Cc: <stable@vger.kernel.org> #v4.19
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
fs/fuse/dev.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 63fd33383413..af78ceead2dc 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -133,9 +133,13 @@ static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
static void fuse_drop_waiting(struct fuse_conn *fc)
{
- if (fc->connected) {
- atomic_dec(&fc->num_waiting);
- } else if (atomic_dec_and_test(&fc->num_waiting)) {
+ /*
+ * lockess check of fc->connected is okay, because atomic_dec_and_test()
+ * provides a memory barrier mached with the one in fuse_wait_aborted()
+ * to ensure no wake-up is missed.
+ */
+ if (atomic_dec_and_test(&fc->num_waiting) &&
+ !READ_ONCE(fc->connected)) {
/* wake up aborters */
wake_up_all(&fc->blocked_waitq);
}
@@ -2170,6 +2174,8 @@ EXPORT_SYMBOL_GPL(fuse_abort_conn);
void fuse_wait_aborted(struct fuse_conn *fc)
{
+ /* matches implicit memory barrier in fuse_drop_waiting() */
+ smp_mb();
wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
}
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags
[not found] <20190507053826.31622-1-sashal@kernel.org>
2019-05-07 5:37 ` [PATCH AUTOSEL 4.14 47/95] fuse: fix possibly missed wake-up after abort Sasha Levin
@ 2019-05-07 5:37 ` Sasha Levin
2019-05-07 13:23 ` Jan Kara
1 sibling, 1 reply; 4+ messages in thread
From: Sasha Levin @ 2019-05-07 5:37 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Amir Goldstein, Jan Kara, Sasha Levin, linux-fsdevel
From: Amir Goldstein <amir73il@gmail.com>
[ Upstream commit 007d1e8395eaa59b0e7ad9eb2b53a40859446a88 ]
FS_EVENT_ON_CHILD gets a special treatment in fsnotify() because it is
not a flag specifying an event type, but rather an extra flags that may
be reported along with another event and control the handling of the
event by the backend.
FS_ISDIR is also an "extra flag" and not an "event type" and therefore
desrves the same treatment. With inotify/dnotify backends it was never
possible to set FS_ISDIR in mark masks, so it did not matter.
With fanotify backend, mark adding code jumps through hoops to avoid
setting the FS_ISDIR in the commulative object mask.
Separate the constant ALL_FSNOTIFY_EVENTS to ALL_FSNOTIFY_FLAGS and
ALL_FSNOTIFY_EVENTS, so the latter can be used to test for specific
event types.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
fs/notify/fsnotify.c | 7 +++----
include/linux/fsnotify_backend.h | 9 +++++++--
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 506da82ff3f1..dc080c642dd0 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -192,7 +192,7 @@ static int send_to_group(struct inode *to_tell,
struct fsnotify_iter_info *iter_info)
{
struct fsnotify_group *group = NULL;
- __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
+ __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
__u32 marks_mask = 0;
__u32 marks_ignored_mask = 0;
@@ -256,8 +256,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
struct fsnotify_iter_info iter_info;
struct mount *mnt;
int ret = 0;
- /* global tests shouldn't care about events on child only the specific event */
- __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
+ __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
if (data_is == FSNOTIFY_EVENT_PATH)
mnt = real_mount(((const struct path *)data)->mnt);
@@ -380,7 +379,7 @@ static __init int fsnotify_init(void)
{
int ret;
- BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
+ BUG_ON(hweight32(ALL_FSNOTIFY_BITS) != 23);
ret = init_srcu_struct(&fsnotify_mark_srcu);
if (ret)
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index ce74278a454a..81052313adeb 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -67,15 +67,20 @@
#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
+/* Events that can be reported to backends */
#define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
- FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
- FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
+ FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME)
+
+/* Extra flags that may be reported with event or control handling of events */
+#define ALL_FSNOTIFY_FLAGS (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
+#define ALL_FSNOTIFY_BITS (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)
+
struct fsnotify_group;
struct fsnotify_event;
struct fsnotify_mark;
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags
2019-05-07 5:37 ` [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags Sasha Levin
@ 2019-05-07 13:23 ` Jan Kara
2019-05-07 16:29 ` Sasha Levin
0 siblings, 1 reply; 4+ messages in thread
From: Jan Kara @ 2019-05-07 13:23 UTC (permalink / raw)
To: Sasha Levin
Cc: linux-kernel, stable, Amir Goldstein, Jan Kara, Sasha Levin,
linux-fsdevel
On Tue 07-05-19 01:37:39, Sasha Levin wrote:
> From: Amir Goldstein <amir73il@gmail.com>
>
> [ Upstream commit 007d1e8395eaa59b0e7ad9eb2b53a40859446a88 ]
>
> FS_EVENT_ON_CHILD gets a special treatment in fsnotify() because it is
> not a flag specifying an event type, but rather an extra flags that may
> be reported along with another event and control the handling of the
> event by the backend.
>
> FS_ISDIR is also an "extra flag" and not an "event type" and therefore
> desrves the same treatment. With inotify/dnotify backends it was never
> possible to set FS_ISDIR in mark masks, so it did not matter.
> With fanotify backend, mark adding code jumps through hoops to avoid
> setting the FS_ISDIR in the commulative object mask.
>
> Separate the constant ALL_FSNOTIFY_EVENTS to ALL_FSNOTIFY_FLAGS and
> ALL_FSNOTIFY_EVENTS, so the latter can be used to test for specific
> event types.
>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Sasha, why did you select this patch? It is just a cleanup with no user
visible effect and was done mostly to simplify implementing following
features...
Honza
> ---
> fs/notify/fsnotify.c | 7 +++----
> include/linux/fsnotify_backend.h | 9 +++++++--
> 2 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 506da82ff3f1..dc080c642dd0 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -192,7 +192,7 @@ static int send_to_group(struct inode *to_tell,
> struct fsnotify_iter_info *iter_info)
> {
> struct fsnotify_group *group = NULL;
> - __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
> + __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
> __u32 marks_mask = 0;
> __u32 marks_ignored_mask = 0;
>
> @@ -256,8 +256,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
> struct fsnotify_iter_info iter_info;
> struct mount *mnt;
> int ret = 0;
> - /* global tests shouldn't care about events on child only the specific event */
> - __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
> + __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
>
> if (data_is == FSNOTIFY_EVENT_PATH)
> mnt = real_mount(((const struct path *)data)->mnt);
> @@ -380,7 +379,7 @@ static __init int fsnotify_init(void)
> {
> int ret;
>
> - BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
> + BUG_ON(hweight32(ALL_FSNOTIFY_BITS) != 23);
>
> ret = init_srcu_struct(&fsnotify_mark_srcu);
> if (ret)
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index ce74278a454a..81052313adeb 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -67,15 +67,20 @@
>
> #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
>
> +/* Events that can be reported to backends */
> #define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
> FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
> FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
> FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
> FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
> - FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
> - FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
> + FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME)
> +
> +/* Extra flags that may be reported with event or control handling of events */
> +#define ALL_FSNOTIFY_FLAGS (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
> FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
>
> +#define ALL_FSNOTIFY_BITS (ALL_FSNOTIFY_EVENTS | ALL_FSNOTIFY_FLAGS)
> +
> struct fsnotify_group;
> struct fsnotify_event;
> struct fsnotify_mark;
> --
> 2.20.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags
2019-05-07 13:23 ` Jan Kara
@ 2019-05-07 16:29 ` Sasha Levin
0 siblings, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2019-05-07 16:29 UTC (permalink / raw)
To: Jan Kara; +Cc: linux-kernel, stable, Amir Goldstein, Sasha Levin, linux-fsdevel
On Tue, May 07, 2019 at 03:23:30PM +0200, Jan Kara wrote:
>On Tue 07-05-19 01:37:39, Sasha Levin wrote:
>> From: Amir Goldstein <amir73il@gmail.com>
>>
>> [ Upstream commit 007d1e8395eaa59b0e7ad9eb2b53a40859446a88 ]
>>
>> FS_EVENT_ON_CHILD gets a special treatment in fsnotify() because it is
>> not a flag specifying an event type, but rather an extra flags that may
>> be reported along with another event and control the handling of the
>> event by the backend.
>>
>> FS_ISDIR is also an "extra flag" and not an "event type" and therefore
>> desrves the same treatment. With inotify/dnotify backends it was never
>> possible to set FS_ISDIR in mark masks, so it did not matter.
>> With fanotify backend, mark adding code jumps through hoops to avoid
>> setting the FS_ISDIR in the commulative object mask.
>>
>> Separate the constant ALL_FSNOTIFY_EVENTS to ALL_FSNOTIFY_FLAGS and
>> ALL_FSNOTIFY_EVENTS, so the latter can be used to test for specific
>> event types.
>>
>> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
>> Signed-off-by: Jan Kara <jack@suse.cz>
>> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
>
>Sasha, why did you select this patch? It is just a cleanup with no user
>visible effect and was done mostly to simplify implementing following
>features...
Sigh, my script picked up the patch after this one (by mistake). I've
dropped that one but missed this one twice(!). Thanks for the heads-up,
I'll drop it.
--
Thanks,
Sasha
^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] <20190507053826.31622-1-sashal@kernel.org>
2019-05-07 5:37 ` [PATCH AUTOSEL 4.14 47/95] fuse: fix possibly missed wake-up after abort Sasha Levin
2019-05-07 5:37 ` [PATCH AUTOSEL 4.14 50/95] fsnotify: generalize handling of extra event flags Sasha Levin
2019-05-07 13:23 ` Jan Kara
2019-05-07 16:29 ` Sasha Levin
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