kernel/git/stable/linux.git/fs/notify, branch linux-4.18.y

fsnotify: Fix busy inodes during unmount

2018-11-13T19:12:47+00:00

commit 721fb6fbfd2132164c2e8777cc837f9b2c1794dc upstream. Detaching of mark connector from fsnotify_put_mark() can race with unmounting of the filesystem like: CPU1 CPU2 fsnotify_put_mark() spin_lock(&conn->lock); ... inode = fsnotify_detach_connector_from_object(conn) spin_unlock(&conn->lock); generic_shutdown_super() fsnotify_unmount_inodes() sees connector detached for inode -> nothing to do evict_inode() barfs on pending inode reference iput(inode); Resulting in "Busy inodes after unmount" message and possible kernel oops. Make fsnotify_unmount_inodes() properly wait for outstanding inode references from detached connectors. Note that the accounting of outstanding inode references in the superblock can cause some cacheline contention on the counter. OTOH it happens only during deletion of the last notification mark from an inode (or during unlinking of watched inode) and that is not too bad. I have measured time to create & delete inotify watch 100000 times from 64 processes in parallel (each process having its own inotify group and its own file on a shared superblock) on a 64 CPU machine. Average and standard deviation of 15 runs look like: Avg Stddev Vanilla 9.817400 0.276165 Fixed 9.710467 0.228294 So there's no statistically significant difference. Fixes: 6b3f05d24d35 ("fsnotify: Detach mark from object list when last reference is dropped") CC: stable@vger.kernel.org Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

fsnotify: fix ignore mask logic in fsnotify()

2018-10-10T06:55:56+00:00

[ Upstream commit 9bdda4e9cf2dcecb60a0683b10ffb8cd7e5f2f45 ] Commit 92183a42898d ("fsnotify: fix ignore mask logic in send_to_group()") acknoledges the use case of ignoring an event on an inode mark, because of an ignore mask on a mount mark of the same group (i.e. I want to get all events on this file, except for the events that came from that mount). This change depends on correctly merging the inode marks and mount marks group lists, so that the mount mark ignore mask would be tested in send_to_group(). Alas, the merging of the lists did not take into account the case where event in question is not in the mask of any of the mount marks. To fix this, completely remove the tests for inode and mount event masks from the lists merging code. Fixes: 92183a42898d ("fsnotify: fix ignore mask logic in send_to_group") Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

fsnotify: add fsnotify_add_inode_mark() wrappers

2018-05-18T12:58:22+00:00

Before changing the arguments of the functions fsnotify_add_mark() and fsnotify_add_mark_locked(), convert most callers to use a wrapper. Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fanotify: generalize fanotify_should_send_event()

2018-05-18T12:58:22+00:00

Use fsnotify_foreach_obj_type macros to generalize the code that filters events by marks mask and ignored_mask. This is going to be used for adding mark of super block object type. Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: generalize send_to_group()

2018-05-18T12:58:22+00:00

fsnotify: generalize iteration of marks by object type

2018-05-18T12:58:22+00:00

Make some code that handles marks of object types inode and vfsmount generic, so it can handle other object types. Introduce fsnotify_foreach_obj_type macro to iterate marks by object type and fsnotify_iter_{should|set}_report_type macros to set/test report_mask. This is going to be used for adding mark of another object type (super block mark). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: introduce marks iteration helpers

2018-05-18T12:58:22+00:00

Introduce helpers fsnotify_iter_select_report_types() and fsnotify_iter_next() to abstract the inode/vfsmount marks merged list iteration. This is a preparation patch before generalizing mark list iteration to more mark object types (i.e. super block marks). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: remove redundant arguments to handle_event()

2018-05-18T12:58:22+00:00

inode_mark and vfsmount_mark arguments are passed to handle_event() operation as function arguments as well as on iter_info struct. The difference is that iter_info struct may contain marks that should not be handled and are represented as NULL arguments to inode_mark or vfsmount_mark. Instead of passing the inode_mark and vfsmount_mark arguments, add a report_mask member to iter_info struct to indicate which marks should be handled, versus marks that should only be kept alive during user wait. This change is going to be used for passing more mark types with handle_event() (i.e. super block marks). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: use type id to identify connector object type

2018-05-18T12:58:22+00:00

An fsnotify_mark_connector is referencing a single type of object (either inode or vfsmount). Instead of storing a type mask in connector->flags, store a single type id in connector->type to identify the type of object. When a connector object is detached from the object, its type is set to FSNOTIFY_OBJ_TYPE_DETACHED and this object is not going to be reused. The function fsnotify_clear_marks_by_group() is the only place where type mask was used, so use type flags instead of type id to this function. This change is going to be more convenient when adding a new object type (super block). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara

fsnotify: fix ignore mask logic in send_to_group()

2018-04-13T13:52:49+00:00

The ignore mask logic in send_to_group() does not match the logic in fanotify_should_send_event(). In the latter, a vfsmount mark ignore mask precedes an inode mark mask and in the former, it does not. That difference may cause events to be sent to fanotify backend for no reason. Fix the logic in send_to_group() to match that of fanotify_should_send_event(). Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara