Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Directory notifications for Linux.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (C) 2000,2001,2002 Stephen Rothwell
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * Copyright (C) 2009 Eric Paris <Red Hat Inc>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  * dnotify was largly rewritten to use the new fsnotify infrastructure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/sched/signal.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/dnotify.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/fdtable.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/fsnotify_backend.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) int dir_notify_enable __read_mostly = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) static struct kmem_cache *dnotify_struct_cache __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) static struct kmem_cache *dnotify_mark_cache __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) static struct fsnotify_group *dnotify_group __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29)  * dnotify will attach one of these to each inode (i_fsnotify_marks) which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  * is being watched by dnotify.  If multiple userspace applications are watching
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  * the same directory with dnotify their information is chained in dn
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) struct dnotify_mark {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	struct fsnotify_mark fsn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	struct dnotify_struct *dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  * When a process starts or stops watching an inode the set of events which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  * dnotify cares about for that inode may change.  This function runs the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  * list of everything receiving dnotify events about this directory and calculates
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * the set of all those events.  After it updates what dnotify is interested in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  * it calls the fsnotify function so it can update the set of all events relevant
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  * to this inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	__u32 new_mask = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	struct dnotify_struct *dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	struct dnotify_mark *dn_mark  = container_of(fsn_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 						     struct dnotify_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 						     fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	assert_spin_locked(&fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	for (dn = dn_mark->dn; dn != NULL; dn = dn->dn_next)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 		new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	if (fsn_mark->mask == new_mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	fsn_mark->mask = new_mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	fsnotify_recalc_mask(fsn_mark->connector);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66)  * Mains fsnotify call where events are delivered to dnotify.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67)  * Find the dnotify mark on the relevant inode, run the list of dnotify structs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68)  * on that mark and determine which of them has expressed interest in receiving
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69)  * events of this type.  When found send the correct process and signal and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70)  * destroy the dnotify struct if it was not registered to receive multiple
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71)  * events.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) static int dnotify_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 				struct inode *inode, struct inode *dir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 				const struct qstr *name, u32 cookie)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	struct dnotify_mark *dn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	struct dnotify_struct *dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	struct dnotify_struct **prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	struct fown_struct *fown;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	__u32 test_mask = mask & ~FS_EVENT_ON_CHILD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	/* not a dir, dnotify doesn't care */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (!dir && !(mask & FS_ISDIR))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	dn_mark = container_of(inode_mark, struct dnotify_mark, fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	spin_lock(&inode_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	prev = &dn_mark->dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	while ((dn = *prev) != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 		if ((dn->dn_mask & test_mask) == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			prev = &dn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 		fown = &dn->dn_filp->f_owner;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		send_sigio(fown, dn->dn_fd, POLL_MSG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		if (dn->dn_mask & FS_DN_MULTISHOT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 			prev = &dn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 			*prev = dn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 			kmem_cache_free(dnotify_struct_cache, dn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 			dnotify_recalc_inode_mask(inode_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	spin_unlock(&inode_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) static void dnotify_free_mark(struct fsnotify_mark *fsn_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	struct dnotify_mark *dn_mark = container_of(fsn_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 						    struct dnotify_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 						    fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	BUG_ON(dn_mark->dn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	kmem_cache_free(dnotify_mark_cache, dn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) static const struct fsnotify_ops dnotify_fsnotify_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	.handle_inode_event = dnotify_handle_event,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	.free_mark = dnotify_free_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  * Called every time a file is closed.  Looks first for a dnotify mark on the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  * inode.  If one is found run all of the ->dn structures attached to that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  * mark for one relevant to this process closing the file and remove that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  * dnotify_struct.  If that was the last dnotify_struct also remove the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)  * fsnotify_mark.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) void dnotify_flush(struct file *filp, fl_owner_t id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	struct fsnotify_mark *fsn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	struct dnotify_mark *dn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	struct dnotify_struct *dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	struct dnotify_struct **prev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	bool free = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	inode = file_inode(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 	if (!S_ISDIR(inode->i_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, dnotify_group);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	if (!fsn_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	mutex_lock(&dnotify_group->mark_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	spin_lock(&fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	prev = &dn_mark->dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	while ((dn = *prev) != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 		if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 			*prev = dn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 			kmem_cache_free(dnotify_struct_cache, dn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 			dnotify_recalc_inode_mask(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		prev = &dn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	spin_unlock(&fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	/* nothing else could have found us thanks to the dnotify_groups
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	   mark_mutex */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	if (dn_mark->dn == NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 		fsnotify_detach_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 		free = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	mutex_unlock(&dnotify_group->mark_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	if (free)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		fsnotify_free_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	fsnotify_put_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) /* this conversion is done only at watch creation */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) static __u32 convert_arg(unsigned long arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	__u32 new_mask = FS_EVENT_ON_CHILD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if (arg & DN_MULTISHOT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		new_mask |= FS_DN_MULTISHOT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	if (arg & DN_DELETE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		new_mask |= (FS_DELETE | FS_MOVED_FROM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	if (arg & DN_MODIFY)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		new_mask |= FS_MODIFY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	if (arg & DN_ACCESS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 		new_mask |= FS_ACCESS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	if (arg & DN_ATTRIB)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		new_mask |= FS_ATTRIB;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	if (arg & DN_RENAME)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		new_mask |= FS_DN_RENAME;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	if (arg & DN_CREATE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 		new_mask |= (FS_CREATE | FS_MOVED_TO);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	return new_mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)  * If multiple processes watch the same inode with dnotify there is only one
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208)  * dnotify mark in inode->i_fsnotify_marks but we chain a dnotify_struct
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)  * onto that mark.  This function either attaches the new dnotify_struct onto
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)  * that list, or it |= the mask onto an existing dnofiy_struct.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark *dn_mark,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 		     fl_owner_t id, int fd, struct file *filp, __u32 mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	struct dnotify_struct *odn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	odn = dn_mark->dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	while (odn != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 		/* adding more events to existing dnofiy_struct? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 		if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 			odn->dn_fd = fd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 			odn->dn_mask |= mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 			return -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		odn = odn->dn_next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 	dn->dn_mask = mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 	dn->dn_fd = fd;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	dn->dn_filp = filp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 	dn->dn_owner = id;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	dn->dn_next = dn_mark->dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 	dn_mark->dn = dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)  * When a process calls fcntl to attach a dnotify watch to a directory it ends
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)  * up here.  Allocate both a mark for fsnotify to add and a dnotify_struct to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241)  * attached to the fsnotify_mark.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	struct dnotify_mark *new_dn_mark, *dn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	struct fsnotify_mark *new_fsn_mark, *fsn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	struct dnotify_struct *dn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	fl_owner_t id = current->files;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	struct file *f;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	int destroy = 0, error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	__u32 mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	/* we use these to tell if we need to kfree */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	new_fsn_mark = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	dn = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	if (!dir_notify_enable) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 		error = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	/* a 0 mask means we are explicitly removing the watch */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	if ((arg & ~DN_MULTISHOT) == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		dnotify_flush(filp, id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	/* dnotify only works on directories */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	inode = file_inode(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	if (!S_ISDIR(inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 		error = -ENOTDIR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 	 * convert the userspace DN_* "arg" to the internal FS_*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	 * defined in fsnotify
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	mask = convert_arg(arg);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	error = security_path_notify(&filp->f_path, mask,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 			FSNOTIFY_OBJ_TYPE_INODE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	if (error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	/* expect most fcntl to add new rather than augment old */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	dn = kmem_cache_alloc(dnotify_struct_cache, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	if (!dn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	/* new fsnotify mark, we expect most fcntl calls to add a new mark */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	if (!new_dn_mark) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 		error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 		goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 	/* set up the new_fsn_mark and new_dn_mark */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 	new_fsn_mark = &new_dn_mark->fsn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 	fsnotify_init_mark(new_fsn_mark, dnotify_group);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	new_fsn_mark->mask = mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 	new_dn_mark->dn = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	/* this is needed to prevent the fcntl/close race described below */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	mutex_lock(&dnotify_group->mark_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 	/* add the new_fsn_mark or find an old one. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, dnotify_group);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	if (fsn_mark) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 		dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 		spin_lock(&fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 		error = fsnotify_add_inode_mark_locked(new_fsn_mark, inode, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 		if (error) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 			mutex_unlock(&dnotify_group->mark_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 			goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		spin_lock(&new_fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 		fsn_mark = new_fsn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 		dn_mark = new_dn_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 		/* we used new_fsn_mark, so don't free it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 		new_fsn_mark = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	f = fcheck(fd);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	/* if (f != filp) means that we lost a race and another task/thread
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	 * actually closed the fd we are still playing with before we grabbed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	 * the dnotify_groups mark_mutex and fsn_mark->lock.  Since closing the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	 * fd is the only time we clean up the marks we need to get our mark
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	 * off the list. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	if (f != filp) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 		/* if we added ourselves, shoot ourselves, it's possible that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 		 * the flush actually did shoot this fsn_mark.  That's fine too
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) 		 * since multiple calls to destroy_mark is perfectly safe, if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 		 * we found a dn_mark already attached to the inode, just sod
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 		 * off silently as the flush at close time dealt with it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) 		if (dn_mark == new_dn_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 			destroy = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) 		error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 	__f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) 	error = attach_dn(dn, dn_mark, id, fd, filp, mask);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 	/* !error means that we attached the dn to the dn_mark, so don't free it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) 	if (!error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) 		dn = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) 	/* -EEXIST means that we didn't add this new dn and used an old one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) 	 * that isn't an error (and the unused dn should be freed) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) 	else if (error == -EEXIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) 		error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) 	dnotify_recalc_inode_mask(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) 	spin_unlock(&fsn_mark->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) 	if (destroy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) 		fsnotify_detach_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) 	mutex_unlock(&dnotify_group->mark_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) 	if (destroy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) 		fsnotify_free_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) 	fsnotify_put_mark(fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) 	if (new_fsn_mark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) 		fsnotify_put_mark(new_fsn_mark);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) 	if (dn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) 		kmem_cache_free(dnotify_struct_cache, dn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) 	return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) static int __init dnotify_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) 	dnotify_struct_cache = KMEM_CACHE(dnotify_struct,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) 					  SLAB_PANIC|SLAB_ACCOUNT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) 	dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC|SLAB_ACCOUNT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) 	dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) 	if (IS_ERR(dnotify_group))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) 		panic("unable to allocate fsnotify group for dnotify\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) module_init(dnotify_init)