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From: Amir Goldstein <amir73il@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org
Subject: [PATCH 15/20] fanotify: prepare for implicit event flags in mark mask
Date: Fri, 12 Jun 2020 12:33:38 +0300	[thread overview]
Message-ID: <20200612093343.5669-16-amir73il@gmail.com> (raw)
In-Reply-To: <20200612093343.5669-1-amir73il@gmail.com>

So far, all flags that can be set in an fanotify mark mask can be set
explicitly by a call to fanotify_mark(2).

Prepare for defining implicit event flags that cannot be set by user with
fanotify_mark(2), similar to how inotify/dnotify implicitly set the
FS_EVENT_ON_CHILD flag.

Implicit event flags cannot be removed by user and mark gets destroyed
when only implicit event flags remain in the mask.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/fanotify/fanotify_user.c | 40 ++++++++++++++++++------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 27bbd67270d8..66d663baa4a6 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -651,12 +651,13 @@ static int fanotify_find_path(int dfd, const char __user *filename,
 }
 
 static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
-					    __u32 mask,
-					    unsigned int flags,
-					    int *destroy)
+					    __u32 mask, unsigned int flags,
+					    __u32 umask, int *destroy)
 {
 	__u32 oldmask = 0;
 
+	/* umask bits cannot be removed by user */
+	mask &= ~umask;
 	spin_lock(&fsn_mark->lock);
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
 		oldmask = fsn_mark->mask;
@@ -664,7 +665,13 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 	} else {
 		fsn_mark->ignored_mask &= ~mask;
 	}
-	*destroy = !(fsn_mark->mask | fsn_mark->ignored_mask);
+	/*
+	 * We need to keep the mark around even if remaining mask cannot
+	 * result in any events (e.g. mask == FAN_ONDIR) to support incremenal
+	 * changes to the mask.
+	 * Destroy mark when only umask bits remain.
+	 */
+	*destroy = !((fsn_mark->mask | fsn_mark->ignored_mask) & ~umask);
 	spin_unlock(&fsn_mark->lock);
 
 	return mask & oldmask;
@@ -672,7 +679,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 
 static int fanotify_remove_mark(struct fsnotify_group *group,
 				fsnotify_connp_t *connp, __u32 mask,
-				unsigned int flags)
+				unsigned int flags, __u32 umask)
 {
 	struct fsnotify_mark *fsn_mark = NULL;
 	__u32 removed;
@@ -686,7 +693,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
 	}
 
 	removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
-						 &destroy_mark);
+						 umask, &destroy_mark);
 	if (removed & fsnotify_conn_mask(fsn_mark->connector))
 		fsnotify_recalc_mask(fsn_mark->connector);
 	if (destroy_mark)
@@ -702,25 +709,26 @@ static int fanotify_remove_mark(struct fsnotify_group *group,
 
 static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
 					 struct vfsmount *mnt, __u32 mask,
-					 unsigned int flags)
+					 unsigned int flags, __u32 umask)
 {
 	return fanotify_remove_mark(group, &real_mount(mnt)->mnt_fsnotify_marks,
-				    mask, flags);
+				    mask, flags, umask);
 }
 
 static int fanotify_remove_sb_mark(struct fsnotify_group *group,
-				      struct super_block *sb, __u32 mask,
-				      unsigned int flags)
+				   struct super_block *sb, __u32 mask,
+				   unsigned int flags, __u32 umask)
 {
-	return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask, flags);
+	return fanotify_remove_mark(group, &sb->s_fsnotify_marks, mask,
+				    flags, umask);
 }
 
 static int fanotify_remove_inode_mark(struct fsnotify_group *group,
 				      struct inode *inode, __u32 mask,
-				      unsigned int flags)
+				      unsigned int flags, __u32 umask)
 {
 	return fanotify_remove_mark(group, &inode->i_fsnotify_marks, mask,
-				    flags);
+				    flags, umask);
 }
 
 static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
@@ -1170,13 +1178,13 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	case FAN_MARK_REMOVE:
 		if (mark_type == FAN_MARK_MOUNT)
 			ret = fanotify_remove_vfsmount_mark(group, mnt, mask,
-							    flags);
+							    flags, 0);
 		else if (mark_type == FAN_MARK_FILESYSTEM)
 			ret = fanotify_remove_sb_mark(group, mnt->mnt_sb, mask,
-						      flags);
+						      flags, 0);
 		else
 			ret = fanotify_remove_inode_mark(group, inode, mask,
-							 flags);
+							 flags, 0);
 		break;
 	default:
 		ret = -EINVAL;
-- 
2.17.1


  parent reply	other threads:[~2020-06-12  9:34 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-12  9:33 [PATCH 00/20] Prep work for fanotify named events Amir Goldstein
2020-06-12  9:33 ` [PATCH 01/20] fsnotify: Rearrange fast path to minimise overhead when there is no watcher Amir Goldstein
2020-07-03 14:03   ` Jan Kara
2020-07-04  9:30     ` Amir Goldstein
2020-07-06 11:05       ` Jan Kara
2020-07-09 17:56         ` fsnotify: minimise overhead when there are no marks with ignore mask Amir Goldstein
2020-07-26 15:20           ` fsnotify: minimise overhead when there are no marks related to sb Amir Goldstein
2020-07-27  7:44             ` Jan Kara
2020-07-27 10:02               ` Amir Goldstein
2020-06-12  9:33 ` [PATCH 02/20] fsnotify: fold fsnotify() call into fsnotify_parent() Amir Goldstein
2020-06-12  9:33 ` [PATCH 03/20] fsnotify: return non const from fsnotify_data_inode() Amir Goldstein
2020-06-12  9:33 ` [PATCH 04/20] nfsd: use fsnotify_data_inode() to get the unlinked inode Amir Goldstein
2020-06-12 10:25   ` Amir Goldstein
2020-06-12  9:33 ` [PATCH 05/20] kernfs: do not call fsnotify() with name without a parent Amir Goldstein
2020-06-29 13:27   ` Tejun Heo
2020-06-29 16:11   ` Greg Kroah-Hartman
2020-06-12  9:33 ` [PATCH 06/20] inotify: do not use objectid when comparing events Amir Goldstein
2020-06-12  9:33 ` [PATCH 07/20] fanotify: create overflow event type Amir Goldstein
2020-06-12  9:33 ` [PATCH 08/20] fanotify: break up fanotify_alloc_event() Amir Goldstein
2020-06-12  9:33 ` [PATCH 09/20] fsnotify: pass dir argument to handle_event() callback Amir Goldstein
2020-07-03 14:49   ` Jan Kara
2020-06-12  9:33 ` [PATCH 10/20] fanotify: generalize the handling of extra event flags Amir Goldstein
2020-06-12  9:33 ` [PATCH 11/20] fanotify: generalize merge logic of events on dir Amir Goldstein
2020-06-12  9:33 ` [PATCH 12/20] fanotify: distinguish between fid encode error and null fid Amir Goldstein
2020-06-12  9:33 ` [PATCH 13/20] fanotify: generalize test for FAN_REPORT_FID Amir Goldstein
2020-06-12  9:33 ` [PATCH 14/20] fanotify: mask out special event flags from ignored mask Amir Goldstein
2020-06-12  9:33 ` Amir Goldstein [this message]
2020-06-12  9:33 ` [PATCH 16/20] fanotify: use FAN_EVENT_ON_CHILD as implicit flag on sb/mount/non-dir marks Amir Goldstein
2020-06-12  9:33 ` [PATCH 17/20] fanotify: remove event FAN_DIR_MODIFY Amir Goldstein
2020-06-12  9:33 ` [PATCH 18/20] fsnotify: add object type "child" to object type iterator Amir Goldstein
2020-06-12  9:33 ` [PATCH 19/20] fanotify: move event name into fanotify_fh Amir Goldstein
2020-07-03 16:02   ` Jan Kara
2020-07-06  8:21     ` Amir Goldstein
2020-07-06 15:24       ` Jan Kara
2020-06-12  9:33 ` [PATCH 20/20] fanotify: no external fh buffer in fanotify_name_event Amir Goldstein

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