| Message ID | 20200702125744.10535-6-amir73il@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fanotify events with name info | expand |
On Thu 02-07-20 15:57:39, Amir Goldstein wrote: > MOVE_SELF event does not get reported to a parent watching children > when a child is moved, but it can be reported to sb/mount mark with > parent/name info if group is interested in parent/name info. > > Use the fsnotify_parent() helper to send a MOVE_SELF event and adjust > fsnotify() to handle the case of an event "on child" that should not > be sent to the watching parent's inode mark. > > Signed-off-by: Amir Goldstein <amir73il@gmail.com> > --- > fs/notify/fsnotify.c | 21 +++++++++++++++++---- > include/linux/fsnotify.h | 5 +---- > include/linux/fsnotify_backend.h | 2 +- > 3 files changed, 19 insertions(+), 9 deletions(-) > > diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c > index 6683c77a5b13..0faf5b09a73e 100644 > --- a/fs/notify/fsnotify.c > +++ b/fs/notify/fsnotify.c > @@ -352,6 +352,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > struct super_block *sb = to_tell->i_sb; > struct inode *dir = S_ISDIR(to_tell->i_mode) ? to_tell : NULL; > struct mount *mnt = NULL; > + struct inode *inode = NULL; > struct inode *child = NULL; > int ret = 0; > __u32 test_mask, marks_mask; > @@ -362,6 +363,14 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > if (mask & FS_EVENT_ON_CHILD) > child = fsnotify_data_inode(data, data_type); > > + /* > + * If event is "on child" then to_tell is a watching parent. > + * An event "on child" may be sent to mount/sb mark with parent/name > + * info, but not appropriate for watching parent (e.g. FS_MOVE_SELF). > + */ > + if (!child || (mask & FS_EVENTS_POSS_ON_CHILD)) > + inode = to_tell; I'm now confused. Don't you want to fill in FSNOTIFY_OBJ_TYPE_INODE below for FS_MOVE_SELF event? But this condition is false for it so you won't do it? > + > /* > * Optimization: srcu_read_lock() has a memory barrier which can > * be expensive. It protects walking the *_fsnotify_marks lists. > @@ -369,14 +378,17 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > * SRCU because we have no references to any objects and do not > * need SRCU to keep them "alive". > */ > - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks && > + if (!sb->s_fsnotify_marks && > (!mnt || !mnt->mnt_fsnotify_marks) && > + (!inode || !inode->i_fsnotify_marks) && > (!child || !child->i_fsnotify_marks)) > return 0; > > - marks_mask = to_tell->i_fsnotify_mask | sb->s_fsnotify_mask; > + marks_mask = sb->s_fsnotify_mask; > if (mnt) > marks_mask |= mnt->mnt_fsnotify_mask; > + if (inode) > + marks_mask |= inode->i_fsnotify_mask; > if (child) > marks_mask |= child->i_fsnotify_mask; > > @@ -390,14 +402,15 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > > iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); > > - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = > - fsnotify_first_mark(&to_tell->i_fsnotify_marks); > iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = > fsnotify_first_mark(&sb->s_fsnotify_marks); > if (mnt) { > iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = > fsnotify_first_mark(&mnt->mnt_fsnotify_marks); > } > + if (inode) > + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = > + fsnotify_first_mark(&inode->i_fsnotify_marks); > if (child) { > iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] = > fsnotify_first_mark(&child->i_fsnotify_marks); > diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h > index 044cae3a0628..61dccaf21e7b 100644 > --- a/include/linux/fsnotify.h > +++ b/include/linux/fsnotify.h > @@ -131,7 +131,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > u32 fs_cookie = fsnotify_get_cookie(); > __u32 old_dir_mask = FS_MOVED_FROM; > __u32 new_dir_mask = FS_MOVED_TO; > - __u32 mask = FS_MOVE_SELF; > const struct qstr *new_name = &moved->d_name; > > if (old_dir == new_dir) > @@ -140,7 +139,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > if (isdir) { > old_dir_mask |= FS_ISDIR; > new_dir_mask |= FS_ISDIR; > - mask |= FS_ISDIR; > } > > fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie); > @@ -149,8 +147,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > if (target) > fsnotify_link_count(target); > > - if (source) > - fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0); > + fsnotify_dentry(moved, FS_MOVE_SELF); I'm somewhat unsure about this. Does this mean that 'moved' is guaranteed to be positive or that you've made sure that all the code below fsnotify_dentry() is actually fine with a negative dentry? I don't find either trivial to verify so some note in a changelog or maybe even a separate patch for this would be useful. Honza
On Tue, Jul 14, 2020 at 3:13 PM Jan Kara <jack@suse.cz> wrote: > > On Thu 02-07-20 15:57:39, Amir Goldstein wrote: > > MOVE_SELF event does not get reported to a parent watching children > > when a child is moved, but it can be reported to sb/mount mark with > > parent/name info if group is interested in parent/name info. > > > > Use the fsnotify_parent() helper to send a MOVE_SELF event and adjust > > fsnotify() to handle the case of an event "on child" that should not > > be sent to the watching parent's inode mark. > > > > Signed-off-by: Amir Goldstein <amir73il@gmail.com> > > --- > > fs/notify/fsnotify.c | 21 +++++++++++++++++---- > > include/linux/fsnotify.h | 5 +---- > > include/linux/fsnotify_backend.h | 2 +- > > 3 files changed, 19 insertions(+), 9 deletions(-) > > > > diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c > > index 6683c77a5b13..0faf5b09a73e 100644 > > --- a/fs/notify/fsnotify.c > > +++ b/fs/notify/fsnotify.c > > @@ -352,6 +352,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > > struct super_block *sb = to_tell->i_sb; > > struct inode *dir = S_ISDIR(to_tell->i_mode) ? to_tell : NULL; > > struct mount *mnt = NULL; > > + struct inode *inode = NULL; > > struct inode *child = NULL; > > int ret = 0; > > __u32 test_mask, marks_mask; > > @@ -362,6 +363,14 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > > if (mask & FS_EVENT_ON_CHILD) > > child = fsnotify_data_inode(data, data_type); > > > > + /* > > + * If event is "on child" then to_tell is a watching parent. > > + * An event "on child" may be sent to mount/sb mark with parent/name > > + * info, but not appropriate for watching parent (e.g. FS_MOVE_SELF). > > + */ > > + if (!child || (mask & FS_EVENTS_POSS_ON_CHILD)) > > + inode = to_tell; > > I'm now confused. Don't you want to fill in FSNOTIFY_OBJ_TYPE_INODE below > for FS_MOVE_SELF event? But this condition is false for it so you won't do > it? > I do not. For events with the flag FS_EVENT_ON_CHILD, the inode in FSNOTIFY_OBJ_TYPE_INODE is always the parent and the inode in FSNOTIFY_OBJ_TYPE_CHILD is always the child. So FS_MOVE_SELF will be reported if sb/mount are watching or if child inode is watching, but NOT if only parent inode is watching. I realize I may have been able to make other choices, but seemed like the most consistent choice to me. If you see a better option, let me know. > > + > > /* > > * Optimization: srcu_read_lock() has a memory barrier which can > > * be expensive. It protects walking the *_fsnotify_marks lists. > > @@ -369,14 +378,17 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > > * SRCU because we have no references to any objects and do not > > * need SRCU to keep them "alive". > > */ > > - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks && > > + if (!sb->s_fsnotify_marks && > > (!mnt || !mnt->mnt_fsnotify_marks) && > > + (!inode || !inode->i_fsnotify_marks) && > > (!child || !child->i_fsnotify_marks)) > > return 0; > > > > - marks_mask = to_tell->i_fsnotify_mask | sb->s_fsnotify_mask; > > + marks_mask = sb->s_fsnotify_mask; > > if (mnt) > > marks_mask |= mnt->mnt_fsnotify_mask; > > + if (inode) > > + marks_mask |= inode->i_fsnotify_mask; > > if (child) > > marks_mask |= child->i_fsnotify_mask; > > > > @@ -390,14 +402,15 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, > > > > iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); > > > > - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = > > - fsnotify_first_mark(&to_tell->i_fsnotify_marks); > > iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = > > fsnotify_first_mark(&sb->s_fsnotify_marks); > > if (mnt) { > > iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = > > fsnotify_first_mark(&mnt->mnt_fsnotify_marks); > > } > > + if (inode) > > + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = > > + fsnotify_first_mark(&inode->i_fsnotify_marks); > > if (child) { > > iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] = > > fsnotify_first_mark(&child->i_fsnotify_marks); > > diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h > > index 044cae3a0628..61dccaf21e7b 100644 > > --- a/include/linux/fsnotify.h > > +++ b/include/linux/fsnotify.h > > @@ -131,7 +131,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > > u32 fs_cookie = fsnotify_get_cookie(); > > __u32 old_dir_mask = FS_MOVED_FROM; > > __u32 new_dir_mask = FS_MOVED_TO; > > - __u32 mask = FS_MOVE_SELF; > > const struct qstr *new_name = &moved->d_name; > > > > if (old_dir == new_dir) > > @@ -140,7 +139,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > > if (isdir) { > > old_dir_mask |= FS_ISDIR; > > new_dir_mask |= FS_ISDIR; > > - mask |= FS_ISDIR; > > } > > > > fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie); > > @@ -149,8 +147,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, > > if (target) > > fsnotify_link_count(target); > > > > - if (source) > > - fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0); > > + fsnotify_dentry(moved, FS_MOVE_SELF); > > I'm somewhat unsure about this. Does this mean that 'moved' is guaranteed > to be positive or that you've made sure that all the code below > fsnotify_dentry() is actually fine with a negative dentry? I don't find > either trivial to verify so some note in a changelog or maybe even a > separate patch for this would be useful. > Oh, it's true. I should've mentioned it or separate this change. I guess my reaction was the opposite of yours - it seemed obvious to me that moved dentry is positive - vfs_rename() is called under lock_rename() and it seemed obvious to me that callers verified positive source, but in any case, vfs_rename() starts with may_delete() that verifies positive rename victim and debugfs_rename(), the other caller of fsnotify_move() also verifies positive victim. I will add this information to the commit message. Thanks, Amir.
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 6683c77a5b13..0faf5b09a73e 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -352,6 +352,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, struct super_block *sb = to_tell->i_sb; struct inode *dir = S_ISDIR(to_tell->i_mode) ? to_tell : NULL; struct mount *mnt = NULL; + struct inode *inode = NULL; struct inode *child = NULL; int ret = 0; __u32 test_mask, marks_mask; @@ -362,6 +363,14 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, if (mask & FS_EVENT_ON_CHILD) child = fsnotify_data_inode(data, data_type); + /* + * If event is "on child" then to_tell is a watching parent. + * An event "on child" may be sent to mount/sb mark with parent/name + * info, but not appropriate for watching parent (e.g. FS_MOVE_SELF). + */ + if (!child || (mask & FS_EVENTS_POSS_ON_CHILD)) + inode = to_tell; + /* * Optimization: srcu_read_lock() has a memory barrier which can * be expensive. It protects walking the *_fsnotify_marks lists. @@ -369,14 +378,17 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, * SRCU because we have no references to any objects and do not * need SRCU to keep them "alive". */ - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks && + if (!sb->s_fsnotify_marks && (!mnt || !mnt->mnt_fsnotify_marks) && + (!inode || !inode->i_fsnotify_marks) && (!child || !child->i_fsnotify_marks)) return 0; - marks_mask = to_tell->i_fsnotify_mask | sb->s_fsnotify_mask; + marks_mask = sb->s_fsnotify_mask; if (mnt) marks_mask |= mnt->mnt_fsnotify_mask; + if (inode) + marks_mask |= inode->i_fsnotify_mask; if (child) marks_mask |= child->i_fsnotify_mask; @@ -390,14 +402,15 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type, iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = - fsnotify_first_mark(&to_tell->i_fsnotify_marks); iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = fsnotify_first_mark(&sb->s_fsnotify_marks); if (mnt) { iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = fsnotify_first_mark(&mnt->mnt_fsnotify_marks); } + if (inode) + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = + fsnotify_first_mark(&inode->i_fsnotify_marks); if (child) { iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] = fsnotify_first_mark(&child->i_fsnotify_marks); diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 044cae3a0628..61dccaf21e7b 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -131,7 +131,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, u32 fs_cookie = fsnotify_get_cookie(); __u32 old_dir_mask = FS_MOVED_FROM; __u32 new_dir_mask = FS_MOVED_TO; - __u32 mask = FS_MOVE_SELF; const struct qstr *new_name = &moved->d_name; if (old_dir == new_dir) @@ -140,7 +139,6 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, if (isdir) { old_dir_mask |= FS_ISDIR; new_dir_mask |= FS_ISDIR; - mask |= FS_ISDIR; } fsnotify_name(old_dir, old_dir_mask, source, old_name, fs_cookie); @@ -149,8 +147,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, if (target) fsnotify_link_count(target); - if (source) - fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0); + fsnotify_dentry(moved, FS_MOVE_SELF); audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE); } diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index a7363c33211e..28f6cf704875 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -89,7 +89,7 @@ * It may include events that can be sent to an inode/sb/mount mark, but cannot * be sent to a parent watching children. */ -#define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD) +#define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD | FS_MOVE_SELF) /* Events that can be reported to backends */ #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \
MOVE_SELF event does not get reported to a parent watching children when a child is moved, but it can be reported to sb/mount mark with parent/name info if group is interested in parent/name info. Use the fsnotify_parent() helper to send a MOVE_SELF event and adjust fsnotify() to handle the case of an event "on child" that should not be sent to the watching parent's inode mark. Signed-off-by: Amir Goldstein <amir73il@gmail.com> --- fs/notify/fsnotify.c | 21 +++++++++++++++++---- include/linux/fsnotify.h | 5 +---- include/linux/fsnotify_backend.h | 2 +- 3 files changed, 19 insertions(+), 9 deletions(-)