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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/dnotify.c
downloadlinux-linaro-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/dnotify.c')
-rw-r--r--fs/dnotify.c183
1 files changed, 183 insertions, 0 deletions
diff --git a/fs/dnotify.c b/fs/dnotify.c
new file mode 100644
index 000000000000..f3b540dd5d11
--- /dev/null
+++ b/fs/dnotify.c
@@ -0,0 +1,183 @@
+/*
+ * 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>
+
+int dir_notify_enable = 1;
+
+static kmem_cache_t *dn_cache;
+
+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_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;
+ int error = 0;
+
+ if ((arg & ~DN_MULTISHOT) == 0) {
+ dnotify_flush(filp, id);
+ return 0;
+ }
+ if (!dir_notify_enable)
+ return -EINVAL;
+ inode = filp->f_dentry->d_inode;
+ if (!S_ISDIR(inode->i_mode))
+ return -ENOTDIR;
+ dn = kmem_cache_alloc(dn_cache, SLAB_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;
+ }
+
+ error = f_setown(filp, current->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);
+
+ if (filp->f_op && filp->f_op->dir_notify)
+ return filp->f_op->dir_notify(filp, arg);
+ 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, NULL);
+ return 0;
+}
+
+module_init(dnotify_init)