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authormerge <null@invalid>2009-01-22 13:55:32 +0000
committerAndy Green <agreen@octopus.localdomain>2009-01-22 13:55:32 +0000
commitaa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 (patch)
treefbb786d0ac6f8a774fd834e9ce951197e60fbffa /fs/notify/dnotify
parentf2d78193eae5dccd3d588d2c8ea0866efc368332 (diff)
MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141
pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage: From: merge <null@invalid> MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage: From: merge <null@invalid> MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage: From: Andy Green <andy@openmoko.com> fix-stray-endmenu.patch Signed-off-by: Andy Green <andy@openmoko.com>
Diffstat (limited to 'fs/notify/dnotify')
-rw-r--r--fs/notify/dnotify/Kconfig10
-rw-r--r--fs/notify/dnotify/Makefile1
-rw-r--r--fs/notify/dnotify/dnotify.c191
3 files changed, 202 insertions, 0 deletions
diff --git a/fs/notify/dnotify/Kconfig b/fs/notify/dnotify/Kconfig
new file mode 100644
index 00000000000..26adf5dfa64
--- /dev/null
+++ b/fs/notify/dnotify/Kconfig
@@ -0,0 +1,10 @@
+config DNOTIFY
+ bool "Dnotify support"
+ default y
+ help
+ Dnotify is a directory-based per-fd file change notification system
+ that uses signals to communicate events to user-space. There exist
+ superior alternatives, but some applications may still rely on
+ dnotify.
+
+ If unsure, say Y.
diff --git a/fs/notify/dnotify/Makefile b/fs/notify/dnotify/Makefile
new file mode 100644
index 00000000000..f145251dcad
--- /dev/null
+++ b/fs/notify/dnotify/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_DNOTIFY) += dnotify.o
diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
new file mode 100644
index 00000000000..b0aa2cde80b
--- /dev/null
+++ b/fs/notify/dnotify/dnotify.c
@@ -0,0 +1,191 @@
+/*
+ * Directory notifications for Linux.
+ *
+ * Copyright (C) 2000,2001,2002 Stephen Rothwell
+ *
+ * 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>
+
+int dir_notify_enable __read_mostly = 1;
+
+static struct kmem_cache *dn_cache __read_mostly;
+
+static void redo_inode_mask(struct inode *inode)
+{
+ unsigned long new_mask;
+ struct dnotify_struct *dn;
+
+ new_mask = 0;
+ for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next)
+ new_mask |= dn->dn_mask & ~DN_MULTISHOT;
+ inode->i_dnotify_mask = new_mask;
+}
+
+void dnotify_flush(struct file *filp, fl_owner_t id)
+{
+ struct dnotify_struct *dn;
+ struct dnotify_struct **prev;
+ struct inode *inode;
+
+ inode = filp->f_path.dentry->d_inode;
+ if (!S_ISDIR(inode->i_mode))
+ return;
+ spin_lock(&inode->i_lock);
+ prev = &inode->i_dnotify;
+ while ((dn = *prev) != NULL) {
+ if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
+ *prev = dn->dn_next;
+ redo_inode_mask(inode);
+ kmem_cache_free(dn_cache, dn);
+ break;
+ }
+ prev = &dn->dn_next;
+ }
+ spin_unlock(&inode->i_lock);
+}
+
+int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
+{
+ struct dnotify_struct *dn;
+ struct dnotify_struct *odn;
+ struct dnotify_struct **prev;
+ struct inode *inode;
+ fl_owner_t id = current->files;
+ struct file *f;
+ int error = 0;
+
+ if ((arg & ~DN_MULTISHOT) == 0) {
+ dnotify_flush(filp, id);
+ return 0;
+ }
+ if (!dir_notify_enable)
+ return -EINVAL;
+ inode = filp->f_path.dentry->d_inode;
+ if (!S_ISDIR(inode->i_mode))
+ return -ENOTDIR;
+ dn = kmem_cache_alloc(dn_cache, GFP_KERNEL);
+ if (dn == NULL)
+ return -ENOMEM;
+ spin_lock(&inode->i_lock);
+ prev = &inode->i_dnotify;
+ while ((odn = *prev) != NULL) {
+ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
+ odn->dn_fd = fd;
+ odn->dn_mask |= arg;
+ inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
+ goto out_free;
+ }
+ prev = &odn->dn_next;
+ }
+
+ rcu_read_lock();
+ f = fcheck(fd);
+ rcu_read_unlock();
+ /* we'd lost the race with close(), sod off silently */
+ /* note that inode->i_lock prevents reordering problems
+ * between accesses to descriptor table and ->i_dnotify */
+ if (f != filp)
+ goto out_free;
+
+ error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
+ if (error)
+ goto out_free;
+
+ dn->dn_mask = arg;
+ dn->dn_fd = fd;
+ dn->dn_filp = filp;
+ dn->dn_owner = id;
+ inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
+ dn->dn_next = inode->i_dnotify;
+ inode->i_dnotify = dn;
+ spin_unlock(&inode->i_lock);
+ return 0;
+
+out_free:
+ spin_unlock(&inode->i_lock);
+ kmem_cache_free(dn_cache, dn);
+ return error;
+}
+
+void __inode_dir_notify(struct inode *inode, unsigned long event)
+{
+ struct dnotify_struct * dn;
+ struct dnotify_struct **prev;
+ struct fown_struct * fown;
+ int changed = 0;
+
+ spin_lock(&inode->i_lock);
+ prev = &inode->i_dnotify;
+ while ((dn = *prev) != NULL) {
+ if ((dn->dn_mask & event) == 0) {
+ prev = &dn->dn_next;
+ continue;
+ }
+ fown = &dn->dn_filp->f_owner;
+ send_sigio(fown, dn->dn_fd, POLL_MSG);
+ if (dn->dn_mask & DN_MULTISHOT)
+ prev = &dn->dn_next;
+ else {
+ *prev = dn->dn_next;
+ changed = 1;
+ kmem_cache_free(dn_cache, dn);
+ }
+ }
+ if (changed)
+ redo_inode_mask(inode);
+ spin_unlock(&inode->i_lock);
+}
+
+EXPORT_SYMBOL(__inode_dir_notify);
+
+/*
+ * This is hopelessly wrong, but unfixable without API changes. At
+ * least it doesn't oops the kernel...
+ *
+ * To safely access ->d_parent we need to keep d_move away from it. Use the
+ * dentry's d_lock for this.
+ */
+void dnotify_parent(struct dentry *dentry, unsigned long event)
+{
+ struct dentry *parent;
+
+ if (!dir_notify_enable)
+ return;
+
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent;
+ if (parent->d_inode->i_dnotify_mask & event) {
+ dget(parent);
+ spin_unlock(&dentry->d_lock);
+ __inode_dir_notify(parent->d_inode, event);
+ dput(parent);
+ } else {
+ spin_unlock(&dentry->d_lock);
+ }
+}
+EXPORT_SYMBOL_GPL(dnotify_parent);
+
+static int __init dnotify_init(void)
+{
+ dn_cache = kmem_cache_create("dnotify_cache",
+ sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL);
+ return 0;
+}
+
+module_init(dnotify_init)