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fanotify: introduce FAN_MARK_IGNORE
This flag is a new way to configure ignore mask which allows adding and removing the event flags FAN_ONDIR and FAN_EVENT_ON_CHILD in ignore mask. The legacy FAN_MARK_IGNORED_MASK flag would always ignore events on directories and would ignore events on children depending on whether the FAN_EVENT_ON_CHILD flag was set in the (non ignored) mask. FAN_MARK_IGNORE can be used to ignore events on children without setting FAN_EVENT_ON_CHILD in the mark's mask and will not ignore events on directories unconditionally, only when FAN_ONDIR is set in ignore mask. The new behavior is non-downgradable. After calling fanotify_mark() with FAN_MARK_IGNORE once, calling fanotify_mark() with FAN_MARK_IGNORED_MASK on the same object will return EEXIST error. Setting the event flags with FAN_MARK_IGNORE on a non-dir inode mark has no meaning and will return ENOTDIR error. The meaning of FAN_MARK_IGNORED_SURV_MODIFY is preserved with the new FAN_MARK_IGNORE flag, but with a few semantic differences: 1. FAN_MARK_IGNORED_SURV_MODIFY is required for filesystem and mount marks and on an inode mark on a directory. Omitting this flag will return EINVAL or EISDIR error. 2. An ignore mask on a non-directory inode that survives modify could never be downgraded to an ignore mask that does not survive modify. With new FAN_MARK_IGNORE semantics we make that rule explicit - trying to update a surviving ignore mask without the flag FAN_MARK_IGNORED_SURV_MODIFY will return EEXIST error. The conveniene macro FAN_MARK_IGNORE_SURV is added for (FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY), because the common case should use short constant names. Link: https://lore.kernel.org/r/20220629144210.2983229-4-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
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@ -499,6 +499,8 @@ static inline unsigned int fanotify_mark_user_flags(struct fsnotify_mark *mark)
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mflags |= FAN_MARK_IGNORED_SURV_MODIFY;
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mflags |= FAN_MARK_IGNORED_SURV_MODIFY;
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if (mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)
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if (mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)
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mflags |= FAN_MARK_EVICTABLE;
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mflags |= FAN_MARK_EVICTABLE;
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if (mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
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mflags |= FAN_MARK_IGNORE;
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return mflags;
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return mflags;
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}
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}
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@ -1009,7 +1009,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
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mask &= ~umask;
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mask &= ~umask;
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spin_lock(&fsn_mark->lock);
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spin_lock(&fsn_mark->lock);
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oldmask = fsnotify_calc_mask(fsn_mark);
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oldmask = fsnotify_calc_mask(fsn_mark);
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if (!(flags & FAN_MARK_IGNORED_MASK)) {
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if (!(flags & FANOTIFY_MARK_IGNORE_BITS)) {
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fsn_mark->mask &= ~mask;
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fsn_mark->mask &= ~mask;
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} else {
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} else {
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fsn_mark->ignore_mask &= ~mask;
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fsn_mark->ignore_mask &= ~mask;
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@ -1085,15 +1085,24 @@ static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
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unsigned int fan_flags)
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unsigned int fan_flags)
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{
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{
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bool want_iref = !(fan_flags & FAN_MARK_EVICTABLE);
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bool want_iref = !(fan_flags & FAN_MARK_EVICTABLE);
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unsigned int ignore = fan_flags & FANOTIFY_MARK_IGNORE_BITS;
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bool recalc = false;
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bool recalc = false;
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/*
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* When using FAN_MARK_IGNORE for the first time, mark starts using
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* independent event flags in ignore mask. After that, trying to
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* update the ignore mask with the old FAN_MARK_IGNORED_MASK API
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* will result in EEXIST error.
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*/
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if (ignore == FAN_MARK_IGNORE)
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fsn_mark->flags |= FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS;
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/*
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/*
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* Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to
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* Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to
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* the removal of the FS_MODIFY bit in calculated mask if it was set
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* the removal of the FS_MODIFY bit in calculated mask if it was set
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* because of an ignore mask that is now going to survive FS_MODIFY.
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* because of an ignore mask that is now going to survive FS_MODIFY.
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*/
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*/
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if ((fan_flags & FAN_MARK_IGNORED_MASK) &&
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if (ignore && (fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
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(fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
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!(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) {
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!(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) {
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fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
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fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
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if (!(fsn_mark->mask & FS_MODIFY))
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if (!(fsn_mark->mask & FS_MODIFY))
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@ -1120,7 +1129,7 @@ static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
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bool recalc;
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bool recalc;
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spin_lock(&fsn_mark->lock);
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spin_lock(&fsn_mark->lock);
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if (!(fan_flags & FAN_MARK_IGNORED_MASK))
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if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS))
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fsn_mark->mask |= mask;
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fsn_mark->mask |= mask;
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else
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else
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fsn_mark->ignore_mask |= mask;
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fsn_mark->ignore_mask |= mask;
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@ -1197,6 +1206,24 @@ static int fanotify_may_update_existing_mark(struct fsnotify_mark *fsn_mark,
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!(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
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!(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
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return -EEXIST;
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return -EEXIST;
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/*
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* New ignore mask semantics cannot be downgraded to old semantics.
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*/
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if (fan_flags & FAN_MARK_IGNORED_MASK &&
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fsn_mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
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return -EEXIST;
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/*
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* An ignore mask that survives modify could never be downgraded to not
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* survive modify. With new FAN_MARK_IGNORE semantics we make that rule
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* explicit and return an error when trying to update the ignore mask
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* without the original FAN_MARK_IGNORED_SURV_MODIFY value.
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*/
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if (fan_flags & FAN_MARK_IGNORE &&
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!(fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
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fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)
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return -EEXIST;
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return 0;
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return 0;
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}
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}
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@ -1231,7 +1258,8 @@ static int fanotify_add_mark(struct fsnotify_group *group,
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* Error events are pre-allocated per group, only if strictly
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* Error events are pre-allocated per group, only if strictly
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* needed (i.e. FAN_FS_ERROR was requested).
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* needed (i.e. FAN_FS_ERROR was requested).
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*/
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*/
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if (!(fan_flags & FAN_MARK_IGNORED_MASK) && (mask & FAN_FS_ERROR)) {
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if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS) &&
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(mask & FAN_FS_ERROR)) {
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ret = fanotify_group_init_error_pool(group);
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ret = fanotify_group_init_error_pool(group);
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if (ret)
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if (ret)
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goto out;
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goto out;
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@ -1275,7 +1303,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
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* an ignore mask, unless that ignore mask is supposed to survive
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* an ignore mask, unless that ignore mask is supposed to survive
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* modification changes anyway.
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* modification changes anyway.
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*/
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*/
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if ((flags & FAN_MARK_IGNORED_MASK) &&
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if ((flags & FANOTIFY_MARK_IGNORE_BITS) &&
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!(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
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!(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
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inode_is_open_for_write(inode))
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inode_is_open_for_write(inode))
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return 0;
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return 0;
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@ -1531,7 +1559,8 @@ static int fanotify_events_supported(struct fsnotify_group *group,
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unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
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unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
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/* Strict validation of events in non-dir inode mask with v5.17+ APIs */
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/* Strict validation of events in non-dir inode mask with v5.17+ APIs */
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bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) ||
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bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) ||
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(mask & FAN_RENAME);
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(mask & FAN_RENAME) ||
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(flags & FAN_MARK_IGNORE);
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/*
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/*
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* Some filesystems such as 'proc' acquire unusual locks when opening
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* Some filesystems such as 'proc' acquire unusual locks when opening
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@ -1569,7 +1598,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
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u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
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u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
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unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
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unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
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unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
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unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
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bool ignore = flags & FAN_MARK_IGNORED_MASK;
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unsigned int ignore = flags & FANOTIFY_MARK_IGNORE_BITS;
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unsigned int obj_type, fid_mode;
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unsigned int obj_type, fid_mode;
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u32 umask = 0;
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u32 umask = 0;
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int ret;
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int ret;
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@ -1618,12 +1647,19 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
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if (mask & ~valid_mask)
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if (mask & ~valid_mask)
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return -EINVAL;
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return -EINVAL;
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/* We don't allow FAN_MARK_IGNORE & FAN_MARK_IGNORED_MASK together */
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if (ignore == (FAN_MARK_IGNORE | FAN_MARK_IGNORED_MASK))
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return -EINVAL;
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/*
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/*
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* Event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) have no effect with
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* Event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) have no effect with
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* FAN_MARK_IGNORED_MASK.
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* FAN_MARK_IGNORED_MASK.
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*/
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*/
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if (ignore)
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if (ignore == FAN_MARK_IGNORED_MASK) {
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mask &= ~FANOTIFY_EVENT_FLAGS;
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mask &= ~FANOTIFY_EVENT_FLAGS;
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umask = FANOTIFY_EVENT_FLAGS;
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}
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f = fdget(fanotify_fd);
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f = fdget(fanotify_fd);
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if (unlikely(!f.file))
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if (unlikely(!f.file))
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else
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else
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mnt = path.mnt;
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mnt = path.mnt;
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ret = mnt ? -EINVAL : -EISDIR;
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/* FAN_MARK_IGNORE requires SURV_MODIFY for sb/mount/dir marks */
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if (mark_cmd == FAN_MARK_ADD && ignore == FAN_MARK_IGNORE &&
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(mnt || S_ISDIR(inode->i_mode)) &&
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!(flags & FAN_MARK_IGNORED_SURV_MODIFY))
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goto path_put_and_out;
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/* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */
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/* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */
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if (mnt || !S_ISDIR(inode->i_mode)) {
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if (mnt || !S_ISDIR(inode->i_mode)) {
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mask &= ~FAN_EVENT_ON_CHILD;
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mask &= ~FAN_EVENT_ON_CHILD;
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@ -1819,7 +1862,7 @@ static int __init fanotify_user_setup(void)
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BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
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BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
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BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
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BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
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BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 10);
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BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 11);
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fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
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fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
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SLAB_PANIC|SLAB_ACCOUNT);
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SLAB_PANIC|SLAB_ACCOUNT);
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@ -62,11 +62,14 @@
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#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
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#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
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FAN_MARK_FLUSH)
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FAN_MARK_FLUSH)
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#define FANOTIFY_MARK_IGNORE_BITS (FAN_MARK_IGNORED_MASK | \
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FAN_MARK_IGNORE)
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#define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
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#define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
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FANOTIFY_MARK_CMD_BITS | \
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FANOTIFY_MARK_CMD_BITS | \
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FANOTIFY_MARK_IGNORE_BITS | \
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FAN_MARK_DONT_FOLLOW | \
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FAN_MARK_DONT_FOLLOW | \
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FAN_MARK_ONLYDIR | \
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FAN_MARK_ONLYDIR | \
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FAN_MARK_IGNORED_MASK | \
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FAN_MARK_IGNORED_SURV_MODIFY | \
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FAN_MARK_IGNORED_SURV_MODIFY | \
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FAN_MARK_EVICTABLE)
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FAN_MARK_EVICTABLE)
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@ -83,12 +83,20 @@
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#define FAN_MARK_FLUSH 0x00000080
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#define FAN_MARK_FLUSH 0x00000080
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/* FAN_MARK_FILESYSTEM is 0x00000100 */
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/* FAN_MARK_FILESYSTEM is 0x00000100 */
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#define FAN_MARK_EVICTABLE 0x00000200
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#define FAN_MARK_EVICTABLE 0x00000200
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/* This bit is mutually exclusive with FAN_MARK_IGNORED_MASK bit */
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#define FAN_MARK_IGNORE 0x00000400
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/* These are NOT bitwise flags. Both bits can be used togther. */
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/* These are NOT bitwise flags. Both bits can be used togther. */
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#define FAN_MARK_INODE 0x00000000
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#define FAN_MARK_INODE 0x00000000
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#define FAN_MARK_MOUNT 0x00000010
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#define FAN_MARK_MOUNT 0x00000010
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#define FAN_MARK_FILESYSTEM 0x00000100
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#define FAN_MARK_FILESYSTEM 0x00000100
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/*
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* Convenience macro - FAN_MARK_IGNORE requires FAN_MARK_IGNORED_SURV_MODIFY
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* for non-inode mark types.
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*/
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#define FAN_MARK_IGNORE_SURV (FAN_MARK_IGNORE | FAN_MARK_IGNORED_SURV_MODIFY)
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/* Deprecated - do not use this in programs and do not add new flags here! */
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/* Deprecated - do not use this in programs and do not add new flags here! */
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#define FAN_ALL_MARK_FLAGS (FAN_MARK_ADD |\
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#define FAN_ALL_MARK_FLAGS (FAN_MARK_ADD |\
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FAN_MARK_REMOVE |\
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FAN_MARK_REMOVE |\
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