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fanotify: allow users to set an ignored_mask
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Change the sys_fanotify_mark() system call so users can set ignored_masks
on inodes.  Remember, if a user new sets a real mask, and only sets ignored
masks, the ignore will never be pinned in memory.  Thus ignored_masks can
be lost under memory pressure and the user may again get events they
previously thought were ignored.

Signed-off-by: Eric Paris <eparis@redhat.com>
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Eric Paris committed Jul 28, 2010
1 parent 32a4df1 commit b9e4e3b
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Showing 2 changed files with 39 additions and 19 deletions.
54 changes: 36 additions & 18 deletions fs/notify/fanotify/fanotify_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -296,13 +296,20 @@ static int fanotify_find_path(int dfd, const char __user *filename,
return ret;
}

static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, __u32 mask)
static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
__u32 mask,
unsigned int flags)
{
__u32 oldmask;

spin_lock(&fsn_mark->lock);
oldmask = fsn_mark->mask;
fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
if (!(flags & FAN_MARK_IGNORED_MASK)) {
oldmask = fsn_mark->mask;
fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask));
} else {
oldmask = fsn_mark->ignored_mask;
fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask));
}
spin_unlock(&fsn_mark->lock);

if (!(oldmask & ~mask))
Expand All @@ -312,7 +319,8 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, __u3
}

static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
struct vfsmount *mnt, __u32 mask)
struct vfsmount *mnt, __u32 mask,
unsigned int flags)
{
struct fsnotify_mark *fsn_mark = NULL;
__u32 removed;
Expand All @@ -321,7 +329,7 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
if (!fsn_mark)
return -ENOENT;

removed = fanotify_mark_remove_from_mask(fsn_mark, mask);
removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
fsnotify_put_mark(fsn_mark);
if (removed & group->mask)
fsnotify_recalc_group_mask(group);
Expand All @@ -332,7 +340,8 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group,
}

static int fanotify_remove_inode_mark(struct fsnotify_group *group,
struct inode *inode, __u32 mask)
struct inode *inode, __u32 mask,
unsigned int flags)
{
struct fsnotify_mark *fsn_mark = NULL;
__u32 removed;
Expand All @@ -341,7 +350,7 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group,
if (!fsn_mark)
return -ENOENT;

removed = fanotify_mark_remove_from_mask(fsn_mark, mask);
removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags);
/* matches the fsnotify_find_inode_mark() */
fsnotify_put_mark(fsn_mark);

Expand All @@ -353,20 +362,28 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group,
return 0;
}

static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, __u32 mask)
static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
__u32 mask,
unsigned int flags)
{
__u32 oldmask;

spin_lock(&fsn_mark->lock);
oldmask = fsn_mark->mask;
fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
if (!(flags & FAN_MARK_IGNORED_MASK)) {
oldmask = fsn_mark->mask;
fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask));
} else {
oldmask = fsn_mark->ignored_mask;
fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask | mask));
}
spin_unlock(&fsn_mark->lock);

return mask & ~oldmask;
}

static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
struct vfsmount *mnt, __u32 mask)
struct vfsmount *mnt, __u32 mask,
unsigned int flags)
{
struct fsnotify_mark *fsn_mark;
__u32 added;
Expand All @@ -386,7 +403,7 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
return ret;
}
}
added = fanotify_mark_add_to_mask(fsn_mark, mask);
added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
fsnotify_put_mark(fsn_mark);
if (added) {
if (added & ~group->mask)
Expand All @@ -398,7 +415,8 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
}

static int fanotify_add_inode_mark(struct fsnotify_group *group,
struct inode *inode, __u32 mask)
struct inode *inode, __u32 mask,
unsigned int flags)
{
struct fsnotify_mark *fsn_mark;
__u32 added;
Expand All @@ -420,7 +438,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
return ret;
}
}
added = fanotify_mark_add_to_mask(fsn_mark, mask);
added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
fsnotify_put_mark(fsn_mark);
if (added) {
if (added & ~group->mask)
Expand Down Expand Up @@ -528,15 +546,15 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
case FAN_MARK_ADD:
if (flags & FAN_MARK_MOUNT)
ret = fanotify_add_vfsmount_mark(group, mnt, mask);
ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags);
else
ret = fanotify_add_inode_mark(group, inode, mask);
ret = fanotify_add_inode_mark(group, inode, mask, flags);
break;
case FAN_MARK_REMOVE:
if (flags & FAN_MARK_MOUNT)
ret = fanotify_remove_vfsmount_mark(group, mnt, mask);
ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags);
else
ret = fanotify_remove_inode_mark(group, inode, mask);
ret = fanotify_remove_inode_mark(group, inode, mask, flags);
break;
default:
ret = -EINVAL;
Expand Down
4 changes: 3 additions & 1 deletion include/linux/fanotify.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,12 +30,14 @@
#define FAN_MARK_DONT_FOLLOW 0x00000004
#define FAN_MARK_ONLYDIR 0x00000008
#define FAN_MARK_MOUNT 0x00000010
#define FAN_MARK_IGNORED_MASK 0x00000020

#define FAN_ALL_MARK_FLAGS (FAN_MARK_ADD |\
FAN_MARK_REMOVE |\
FAN_MARK_DONT_FOLLOW |\
FAN_MARK_ONLYDIR |\
FAN_MARK_MOUNT)
FAN_MARK_MOUNT |\
FAN_MARK_IGNORED_MASK)

/*
* All of the events - we build the list by hand so that we can add flags in
Expand Down

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