[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/fs/notify/dnotify/dnotify.c b/src/kernel/linux/v4.14/fs/notify/dnotify/dnotify.c
new file mode 100644
index 0000000..63a1ca4
--- /dev/null
+++ b/src/kernel/linux/v4.14/fs/notify/dnotify/dnotify.c
@@ -0,0 +1,396 @@
+/*
+ * Directory notifications for Linux.
+ *
+ * Copyright (C) 2000,2001,2002 Stephen Rothwell
+ *
+ * Copyright (C) 2009 Eric Paris <Red Hat Inc>
+ * dnotify was largly rewritten to use the new fsnotify infrastructure
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/dnotify.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/fdtable.h>
+#include <linux/fsnotify_backend.h>
+
+int dir_notify_enable __read_mostly = 1;
+
+static struct kmem_cache *dnotify_struct_cache __read_mostly;
+static struct kmem_cache *dnotify_mark_cache __read_mostly;
+static struct fsnotify_group *dnotify_group __read_mostly;
+
+/*
+ * dnotify will attach one of these to each inode (i_fsnotify_marks) which
+ * is being watched by dnotify. If multiple userspace applications are watching
+ * the same directory with dnotify their information is chained in dn
+ */
+struct dnotify_mark {
+ struct fsnotify_mark fsn_mark;
+ struct dnotify_struct *dn;
+};
+
+/*
+ * When a process starts or stops watching an inode the set of events which
+ * dnotify cares about for that inode may change. This function runs the
+ * list of everything receiving dnotify events about this directory and calculates
+ * the set of all those events. After it updates what dnotify is interested in
+ * it calls the fsnotify function so it can update the set of all events relevant
+ * to this inode.
+ */
+static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark)
+{
+ __u32 new_mask = 0;
+ struct dnotify_struct *dn;
+ struct dnotify_mark *dn_mark = container_of(fsn_mark,
+ struct dnotify_mark,
+ fsn_mark);
+
+ assert_spin_locked(&fsn_mark->lock);
+
+ for (dn = dn_mark->dn; dn != NULL; dn = dn->dn_next)
+ new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT);
+ if (fsn_mark->mask == new_mask)
+ return;
+ fsn_mark->mask = new_mask;
+
+ fsnotify_recalc_mask(fsn_mark->connector);
+}
+
+/*
+ * Mains fsnotify call where events are delivered to dnotify.
+ * Find the dnotify mark on the relevant inode, run the list of dnotify structs
+ * on that mark and determine which of them has expressed interest in receiving
+ * events of this type. When found send the correct process and signal and
+ * destroy the dnotify struct if it was not registered to receive multiple
+ * events.
+ */
+static int dnotify_handle_event(struct fsnotify_group *group,
+ struct inode *inode,
+ struct fsnotify_mark *inode_mark,
+ struct fsnotify_mark *vfsmount_mark,
+ u32 mask, const void *data, int data_type,
+ const unsigned char *file_name, u32 cookie,
+ struct fsnotify_iter_info *iter_info)
+{
+ struct dnotify_mark *dn_mark;
+ struct dnotify_struct *dn;
+ struct dnotify_struct **prev;
+ struct fown_struct *fown;
+ __u32 test_mask = mask & ~FS_EVENT_ON_CHILD;
+
+ /* not a dir, dnotify doesn't care */
+ if (!S_ISDIR(inode->i_mode))
+ return 0;
+
+ BUG_ON(vfsmount_mark);
+
+ dn_mark = container_of(inode_mark, struct dnotify_mark, fsn_mark);
+
+ spin_lock(&inode_mark->lock);
+ prev = &dn_mark->dn;
+ while ((dn = *prev) != NULL) {
+ if ((dn->dn_mask & test_mask) == 0) {
+ prev = &dn->dn_next;
+ continue;
+ }
+ fown = &dn->dn_filp->f_owner;
+ send_sigio(fown, dn->dn_fd, POLL_MSG);
+ if (dn->dn_mask & FS_DN_MULTISHOT)
+ prev = &dn->dn_next;
+ else {
+ *prev = dn->dn_next;
+ kmem_cache_free(dnotify_struct_cache, dn);
+ dnotify_recalc_inode_mask(inode_mark);
+ }
+ }
+
+ spin_unlock(&inode_mark->lock);
+
+ return 0;
+}
+
+static void dnotify_free_mark(struct fsnotify_mark *fsn_mark)
+{
+ struct dnotify_mark *dn_mark = container_of(fsn_mark,
+ struct dnotify_mark,
+ fsn_mark);
+
+ BUG_ON(dn_mark->dn);
+
+ kmem_cache_free(dnotify_mark_cache, dn_mark);
+}
+
+static const struct fsnotify_ops dnotify_fsnotify_ops = {
+ .handle_event = dnotify_handle_event,
+ .free_mark = dnotify_free_mark,
+};
+
+/*
+ * Called every time a file is closed. Looks first for a dnotify mark on the
+ * inode. If one is found run all of the ->dn structures attached to that
+ * mark for one relevant to this process closing the file and remove that
+ * dnotify_struct. If that was the last dnotify_struct also remove the
+ * fsnotify_mark.
+ */
+void dnotify_flush(struct file *filp, fl_owner_t id)
+{
+ struct fsnotify_mark *fsn_mark;
+ struct dnotify_mark *dn_mark;
+ struct dnotify_struct *dn;
+ struct dnotify_struct **prev;
+ struct inode *inode;
+ bool free = false;
+
+ inode = file_inode(filp);
+ if (!S_ISDIR(inode->i_mode))
+ return;
+
+ fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, dnotify_group);
+ if (!fsn_mark)
+ return;
+ dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
+
+ mutex_lock(&dnotify_group->mark_mutex);
+
+ spin_lock(&fsn_mark->lock);
+ prev = &dn_mark->dn;
+ while ((dn = *prev) != NULL) {
+ if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
+ *prev = dn->dn_next;
+ kmem_cache_free(dnotify_struct_cache, dn);
+ dnotify_recalc_inode_mask(fsn_mark);
+ break;
+ }
+ prev = &dn->dn_next;
+ }
+
+ spin_unlock(&fsn_mark->lock);
+
+ /* nothing else could have found us thanks to the dnotify_groups
+ mark_mutex */
+ if (dn_mark->dn == NULL) {
+ fsnotify_detach_mark(fsn_mark);
+ free = true;
+ }
+
+ mutex_unlock(&dnotify_group->mark_mutex);
+
+ if (free)
+ fsnotify_free_mark(fsn_mark);
+ fsnotify_put_mark(fsn_mark);
+}
+
+/* this conversion is done only at watch creation */
+static __u32 convert_arg(unsigned long arg)
+{
+ __u32 new_mask = FS_EVENT_ON_CHILD;
+
+ if (arg & DN_MULTISHOT)
+ new_mask |= FS_DN_MULTISHOT;
+ if (arg & DN_DELETE)
+ new_mask |= (FS_DELETE | FS_MOVED_FROM);
+ if (arg & DN_MODIFY)
+ new_mask |= FS_MODIFY;
+ if (arg & DN_ACCESS)
+ new_mask |= FS_ACCESS;
+ if (arg & DN_ATTRIB)
+ new_mask |= FS_ATTRIB;
+ if (arg & DN_RENAME)
+ new_mask |= FS_DN_RENAME;
+ if (arg & DN_CREATE)
+ new_mask |= (FS_CREATE | FS_MOVED_TO);
+
+ return new_mask;
+}
+
+/*
+ * If multiple processes watch the same inode with dnotify there is only one
+ * dnotify mark in inode->i_fsnotify_marks but we chain a dnotify_struct
+ * onto that mark. This function either attaches the new dnotify_struct onto
+ * that list, or it |= the mask onto an existing dnofiy_struct.
+ */
+static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark *dn_mark,
+ fl_owner_t id, int fd, struct file *filp, __u32 mask)
+{
+ struct dnotify_struct *odn;
+
+ odn = dn_mark->dn;
+ while (odn != NULL) {
+ /* adding more events to existing dnofiy_struct? */
+ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
+ odn->dn_fd = fd;
+ odn->dn_mask |= mask;
+ return -EEXIST;
+ }
+ odn = odn->dn_next;
+ }
+
+ dn->dn_mask = mask;
+ dn->dn_fd = fd;
+ dn->dn_filp = filp;
+ dn->dn_owner = id;
+ dn->dn_next = dn_mark->dn;
+ dn_mark->dn = dn;
+
+ return 0;
+}
+
+/*
+ * When a process calls fcntl to attach a dnotify watch to a directory it ends
+ * up here. Allocate both a mark for fsnotify to add and a dnotify_struct to be
+ * attached to the fsnotify_mark.
+ */
+int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
+{
+ struct dnotify_mark *new_dn_mark, *dn_mark;
+ struct fsnotify_mark *new_fsn_mark, *fsn_mark;
+ struct dnotify_struct *dn;
+ struct inode *inode;
+ fl_owner_t id = current->files;
+ struct file *f;
+ int destroy = 0, error = 0;
+ __u32 mask;
+
+ /* we use these to tell if we need to kfree */
+ new_fsn_mark = NULL;
+ dn = NULL;
+
+ if (!dir_notify_enable) {
+ error = -EINVAL;
+ goto out_err;
+ }
+
+ /* a 0 mask means we are explicitly removing the watch */
+ if ((arg & ~DN_MULTISHOT) == 0) {
+ dnotify_flush(filp, id);
+ error = 0;
+ goto out_err;
+ }
+
+ /* dnotify only works on directories */
+ inode = file_inode(filp);
+ if (!S_ISDIR(inode->i_mode)) {
+ error = -ENOTDIR;
+ goto out_err;
+ }
+
+ /* expect most fcntl to add new rather than augment old */
+ dn = kmem_cache_alloc(dnotify_struct_cache, GFP_KERNEL);
+ if (!dn) {
+ error = -ENOMEM;
+ goto out_err;
+ }
+
+ /* new fsnotify mark, we expect most fcntl calls to add a new mark */
+ new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL);
+ if (!new_dn_mark) {
+ error = -ENOMEM;
+ goto out_err;
+ }
+
+ /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */
+ mask = convert_arg(arg);
+
+ /* set up the new_fsn_mark and new_dn_mark */
+ new_fsn_mark = &new_dn_mark->fsn_mark;
+ fsnotify_init_mark(new_fsn_mark, dnotify_group);
+ new_fsn_mark->mask = mask;
+ new_dn_mark->dn = NULL;
+
+ /* this is needed to prevent the fcntl/close race described below */
+ mutex_lock(&dnotify_group->mark_mutex);
+
+ /* add the new_fsn_mark or find an old one. */
+ fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, dnotify_group);
+ if (fsn_mark) {
+ dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
+ spin_lock(&fsn_mark->lock);
+ } else {
+ error = fsnotify_add_mark_locked(new_fsn_mark, inode, NULL, 0);
+ if (error) {
+ mutex_unlock(&dnotify_group->mark_mutex);
+ goto out_err;
+ }
+ spin_lock(&new_fsn_mark->lock);
+ fsn_mark = new_fsn_mark;
+ dn_mark = new_dn_mark;
+ /* we used new_fsn_mark, so don't free it */
+ new_fsn_mark = NULL;
+ }
+
+ rcu_read_lock();
+ f = fcheck(fd);
+ rcu_read_unlock();
+
+ /* if (f != filp) means that we lost a race and another task/thread
+ * actually closed the fd we are still playing with before we grabbed
+ * the dnotify_groups mark_mutex and fsn_mark->lock. Since closing the
+ * fd is the only time we clean up the marks we need to get our mark
+ * off the list. */
+ if (f != filp) {
+ /* if we added ourselves, shoot ourselves, it's possible that
+ * the flush actually did shoot this fsn_mark. That's fine too
+ * since multiple calls to destroy_mark is perfectly safe, if
+ * we found a dn_mark already attached to the inode, just sod
+ * off silently as the flush at close time dealt with it.
+ */
+ if (dn_mark == new_dn_mark)
+ destroy = 1;
+ error = 0;
+ goto out;
+ }
+
+ __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
+
+ error = attach_dn(dn, dn_mark, id, fd, filp, mask);
+ /* !error means that we attached the dn to the dn_mark, so don't free it */
+ if (!error)
+ dn = NULL;
+ /* -EEXIST means that we didn't add this new dn and used an old one.
+ * that isn't an error (and the unused dn should be freed) */
+ else if (error == -EEXIST)
+ error = 0;
+
+ dnotify_recalc_inode_mask(fsn_mark);
+out:
+ spin_unlock(&fsn_mark->lock);
+
+ if (destroy)
+ fsnotify_detach_mark(fsn_mark);
+ mutex_unlock(&dnotify_group->mark_mutex);
+ if (destroy)
+ fsnotify_free_mark(fsn_mark);
+ fsnotify_put_mark(fsn_mark);
+out_err:
+ if (new_fsn_mark)
+ fsnotify_put_mark(new_fsn_mark);
+ if (dn)
+ kmem_cache_free(dnotify_struct_cache, dn);
+ return error;
+}
+
+static int __init dnotify_init(void)
+{
+ dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC);
+ dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC);
+
+ dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops);
+ if (IS_ERR(dnotify_group))
+ panic("unable to allocate fsnotify group for dnotify\n");
+ return 0;
+}
+
+module_init(dnotify_init)