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fsnotify: introduce marks iteration helpers

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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 <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Amir Goldstein 2018-04-20 16:10:51 -07:00 committed by Jan Kara
parent 5b0457ad02
commit d9a6f30bb8
1 changed files with 49 additions and 25 deletions
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74
fs/notify/fsnotify.c
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@ -260,6 +260,53 @@ static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark)
return hlist_entry_safe(node, struct fsnotify_mark, obj_list);
}
/*
* iter_info is a multi head priority queue of marks.
* Pick a subset of marks from queue heads, all with the
* same group and set the report_mask for selected subset.
* Returns the report_mask of the selected subset.
*/
static unsigned int fsnotify_iter_select_report_types(
struct fsnotify_iter_info *iter_info)
{
struct fsnotify_mark *inode_mark = iter_info->inode_mark;
struct fsnotify_mark *vfsmount_mark = iter_info->vfsmount_mark;
int cmp;
if (!inode_mark && !vfsmount_mark)
return 0;
if (inode_mark && vfsmount_mark) {
cmp = fsnotify_compare_groups(inode_mark->group,
vfsmount_mark->group);
} else {
cmp = inode_mark ? -1 : 1;
}
iter_info->report_mask = 0;
if (cmp <= 0)
iter_info->report_mask |= FSNOTIFY_OBJ_TYPE_INODE_FL;
if (cmp >= 0)
iter_info->report_mask |= FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL;
return iter_info->report_mask;
}
/*
* Pop from iter_info multi head queue, the marks that were iterated in the
* current iteration step.
*/
static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
{
if (iter_info->report_mask & FSNOTIFY_OBJ_TYPE_INODE_FL)
iter_info->inode_mark =
fsnotify_next_mark(iter_info->inode_mark);
if (iter_info->report_mask & FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL)
iter_info->vfsmount_mark =
fsnotify_next_mark(iter_info->vfsmount_mark);
}
/*
* This is the main call to fsnotify. The VFS calls into hook specific functions
* in linux/fsnotify.h. Those functions then in turn call here. Here will call
@ -321,37 +368,14 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is,
* ignore masks are properly reflected for mount mark notifications.
* That's why this traversal is so complicated...
*/
while (iter_info.inode_mark || iter_info.vfsmount_mark) {
struct fsnotify_mark *inode_mark = iter_info.inode_mark;
struct fsnotify_mark *vfsmount_mark = iter_info.vfsmount_mark;
int cmp;
if (inode_mark && vfsmount_mark) {
cmp = fsnotify_compare_groups(inode_mark->group,
vfsmount_mark->group);
} else {
cmp = inode_mark ? -1 : 1;
}
iter_info.report_mask = 0;
if (cmp <= 0)
iter_info.report_mask |= FSNOTIFY_OBJ_TYPE_INODE_FL;
if (cmp >= 0)
iter_info.report_mask |= FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL;
while (fsnotify_iter_select_report_types(&iter_info)) {
ret = send_to_group(to_tell, mask, data, data_is, cookie,
file_name, &iter_info);
if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
goto out;
if (iter_info.report_mask & FSNOTIFY_OBJ_TYPE_INODE_FL)
iter_info.inode_mark =
fsnotify_next_mark(iter_info.inode_mark);
if (iter_info.report_mask & FSNOTIFY_OBJ_TYPE_VFSMOUNT_FL)
iter_info.vfsmount_mark =
fsnotify_next_mark(iter_info.vfsmount_mark);
fsnotify_iter_next(&iter_info);
}
ret = 0;
out: