[RFC/PATCH 0/2] fsnotify/inotify split

[RFC/PATCH 0/2] fsnotify/inotify split

[Chris Wright]

The following two patches simply split fsnotify from inotify.
There should be no functional change to inotify at all.  Perhaps the
split will help identify the interface bits that can easily converge
for inotify and audit.  They're completely untested...  I started with
inotify-45 in 2.6.13-rc2-mm1, and worked against base 2.6.13-rc2.

My first pass was trivial split, this is my second pass which moves
dnotify and inotify functionality out of fsnotify.h into their respective
corners.  I'm sure audit can at least use the hooks, and perhaps more
base inode watch functionality could be shared (at no cost to you! ;-)
moving forward.

thanks,
-chris

[RFC/PATCH 1/2] fsnotify

[Chris Wright]

Add fsnotify as infrastructure for various fs notifcation schemes.
Move dnotify to fsnotify.


 fs/attr.c                |   33 +------------
 fs/compat.c              |   12 +++-
 fs/file_table.c          |    3 +
 fs/namei.c               |   30 ++++++-----
 fs/nfsd/vfs.c            |    6 +-
 fs/open.c                |    3 -
 fs/read_write.c          |   15 +++--
 fs/sysfs/file.c          |    7 --
 fs/xattr.c               |    5 +
 include/linux/dnotify.h  |  101 ++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h       |    1 
 include/linux/fsnotify.h |  118 +++++++++++++++++++++++++++++++++++++++++++++++
 12 files changed, 270 insertions(+), 64 deletions(-)

Index: linux-2.6.13-rc2-fsnotify-2/fs/attr.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/attr.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/attr.c
@@ -10,7 +10,7 @@
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/smp_lock.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/fcntl.h>
 #include <linux/quotaops.h>
 #include <linux/security.h>
@@ -107,31 +107,8 @@ int inode_setattr(struct inode * inode, 
 out:
 	return error;
 }
-
 EXPORT_SYMBOL(inode_setattr);
 
-int setattr_mask(unsigned int ia_valid)
-{
-	unsigned long dn_mask = 0;
-
-	if (ia_valid & ATTR_UID)
-		dn_mask |= DN_ATTRIB;
-	if (ia_valid & ATTR_GID)
-		dn_mask |= DN_ATTRIB;
-	if (ia_valid & ATTR_SIZE)
-		dn_mask |= DN_MODIFY;
-	/* both times implies a utime(s) call */
-	if ((ia_valid & (ATTR_ATIME|ATTR_MTIME)) == (ATTR_ATIME|ATTR_MTIME))
-		dn_mask |= DN_ATTRIB;
-	else if (ia_valid & ATTR_ATIME)
-		dn_mask |= DN_ACCESS;
-	else if (ia_valid & ATTR_MTIME)
-		dn_mask |= DN_MODIFY;
-	if (ia_valid & ATTR_MODE)
-		dn_mask |= DN_ATTRIB;
-	return dn_mask;
-}
-
 int notify_change(struct dentry * dentry, struct iattr * attr)
 {
 	struct inode *inode = dentry->d_inode;
@@ -197,11 +174,9 @@ int notify_change(struct dentry * dentry
 	if (ia_valid & ATTR_SIZE)
 		up_write(&dentry->d_inode->i_alloc_sem);
 
-	if (!error) {
-		unsigned long dn_mask = setattr_mask(ia_valid);
-		if (dn_mask)
-			dnotify_parent(dentry, dn_mask);
-	}
+	if (!error)
+		fsnotify_change(dentry, ia_valid);
+
 	return error;
 }
 
Index: linux-2.6.13-rc2-fsnotify-2/fs/compat.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/compat.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/compat.c
@@ -37,7 +37,7 @@
 #include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/dirent.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/highuid.h>
 #include <linux/sunrpc/svc.h>
 #include <linux/nfsd/nfsd.h>
@@ -1307,9 +1307,13 @@ static ssize_t compat_do_readv_writev(in
 out:
 	if (iov != iovstack)
 		kfree(iov);
-	if ((ret + (type == READ)) > 0)
-		dnotify_parent(file->f_dentry,
-				(type == READ) ? DN_ACCESS : DN_MODIFY);
+	if ((ret + (type == READ)) > 0) {
+		struct dentry *dentry = file->f_dentry;
+		if (type == READ)
+			fsnotify_access(dentry);
+		else
+			fsnotify_modify(dentry);
+	}
 	return ret;
 }
 
Index: linux-2.6.13-rc2-fsnotify-2/fs/file_table.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/file_table.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/file_table.c
@@ -16,6 +16,7 @@
 #include <linux/eventpoll.h>
 #include <linux/mount.h>
 #include <linux/cdev.h>
+#include <linux/fsnotify.h>
 
 /* sysctl tunables... */
 struct files_stat_struct files_stat = {
@@ -126,6 +127,8 @@ void fastcall __fput(struct file *file)
 	struct inode *inode = dentry->d_inode;
 
 	might_sleep();
+
+	fsnotify_close(file);
 	/*
 	 * The function eventpoll_release() should be the first called
 	 * in the file cleanup chain.
Index: linux-2.6.13-rc2-fsnotify-2/fs/namei.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/namei.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/namei.c
@@ -21,7 +21,7 @@
 #include <linux/namei.h>
 #include <linux/quotaops.h>
 #include <linux/pagemap.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/smp_lock.h>
 #include <linux/personality.h>
 #include <linux/security.h>
@@ -1312,7 +1312,7 @@ int vfs_create(struct inode *dir, struct
 	DQUOT_INIT(dir);
 	error = dir->i_op->create(dir, dentry, mode, nd);
 	if (!error) {
-		inode_dir_notify(dir, DN_CREATE);
+		fsnotify_create(dir, dentry->d_name.name);
 		security_inode_post_create(dir, dentry, mode);
 	}
 	return error;
@@ -1637,7 +1637,7 @@ int vfs_mknod(struct inode *dir, struct 
 	DQUOT_INIT(dir);
 	error = dir->i_op->mknod(dir, dentry, mode, dev);
 	if (!error) {
-		inode_dir_notify(dir, DN_CREATE);
+		fsnotify_create(dir, dentry->d_name.name);
 		security_inode_post_mknod(dir, dentry, mode, dev);
 	}
 	return error;
@@ -1710,7 +1710,7 @@ int vfs_mkdir(struct inode *dir, struct 
 	DQUOT_INIT(dir);
 	error = dir->i_op->mkdir(dir, dentry, mode);
 	if (!error) {
-		inode_dir_notify(dir, DN_CREATE);
+		fsnotify_mkdir(dir, dentry->d_name.name);
 		security_inode_post_mkdir(dir,dentry, mode);
 	}
 	return error;
@@ -1801,7 +1801,7 @@ int vfs_rmdir(struct inode *dir, struct 
 	}
 	up(&dentry->d_inode->i_sem);
 	if (!error) {
-		inode_dir_notify(dir, DN_DELETE);
+		fsnotify_rmdir(dentry, dentry->d_inode, dir);
 		d_delete(dentry);
 	}
 	dput(dentry);
@@ -1874,9 +1874,10 @@ int vfs_unlink(struct inode *dir, struct
 
 	/* We don't d_delete() NFS sillyrenamed files--they still exist. */
 	if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
+		fsnotify_unlink(dentry, dir);
 		d_delete(dentry);
-		inode_dir_notify(dir, DN_DELETE);
 	}
+
 	return error;
 }
 
@@ -1950,7 +1951,7 @@ int vfs_symlink(struct inode *dir, struc
 	DQUOT_INIT(dir);
 	error = dir->i_op->symlink(dir, dentry, oldname);
 	if (!error) {
-		inode_dir_notify(dir, DN_CREATE);
+		fsnotify_create(dir, dentry->d_name.name);
 		security_inode_post_symlink(dir, dentry, oldname);
 	}
 	return error;
@@ -2023,7 +2024,7 @@ int vfs_link(struct dentry *old_dentry, 
 	error = dir->i_op->link(old_dentry, dir, new_dentry);
 	up(&old_dentry->d_inode->i_sem);
 	if (!error) {
-		inode_dir_notify(dir, DN_CREATE);
+		fsnotify_create(dir, new_dentry->d_name.name);
 		security_inode_post_link(old_dentry, dir, new_dentry);
 	}
 	return error;
@@ -2187,6 +2188,7 @@ int vfs_rename(struct inode *old_dir, st
 {
 	int error;
 	int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
+	const char *old_name;
 
 	if (old_dentry->d_inode == new_dentry->d_inode)
  		return 0;
@@ -2208,18 +2210,18 @@ int vfs_rename(struct inode *old_dir, st
 	DQUOT_INIT(old_dir);
 	DQUOT_INIT(new_dir);
 
+	old_name = fsnotify_oldname_init(old_dentry->d_name.name);
+
 	if (is_dir)
 		error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
 	else
 		error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
 	if (!error) {
-		if (old_dir == new_dir)
-			inode_dir_notify(old_dir, DN_RENAME);
-		else {
-			inode_dir_notify(old_dir, DN_DELETE);
-			inode_dir_notify(new_dir, DN_CREATE);
-		}
+		const char *new_name = old_dentry->d_name.name;
+		fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir);
 	}
+	fsnotify_oldname_free(old_name);
+
 	return error;
 }
 
Index: linux-2.6.13-rc2-fsnotify-2/fs/nfsd/vfs.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/nfsd/vfs.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/nfsd/vfs.c
@@ -45,7 +45,7 @@
 #endif /* CONFIG_NFSD_V3 */
 #include <linux/nfsd/nfsfh.h>
 #include <linux/quotaops.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
 #ifdef CONFIG_NFSD_V4
@@ -860,7 +860,7 @@ nfsd_vfs_read(struct svc_rqst *rqstp, st
 		nfsdstats.io_read += err;
 		*count = err;
 		err = 0;
-		dnotify_parent(file->f_dentry, DN_ACCESS);
+		fsnotify_access(file->f_dentry);
 	} else 
 		err = nfserrno(err);
 out:
@@ -916,7 +916,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s
 	set_fs(oldfs);
 	if (err >= 0) {
 		nfsdstats.io_write += cnt;
-		dnotify_parent(file->f_dentry, DN_MODIFY);
+		fsnotify_modify(file->f_dentry);
 	}
 
 	/* clear setuid/setgid flag after write */
Index: linux-2.6.13-rc2-fsnotify-2/fs/open.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/open.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/open.c
@@ -10,7 +10,7 @@
 #include <linux/file.h>
 #include <linux/smp_lock.h>
 #include <linux/quotaops.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/tty.h>
@@ -951,6 +951,7 @@ asmlinkage long sys_open(const char __us
 				put_unused_fd(fd);
 				fd = PTR_ERR(f);
 			} else {
+				fsnotify_open(f->f_dentry);
 				fd_install(fd, f);
 			}
 		}
Index: linux-2.6.13-rc2-fsnotify-2/fs/read_write.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/read_write.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/read_write.c
@@ -10,7 +10,7 @@
 #include <linux/file.h>
 #include <linux/uio.h>
 #include <linux/smp_lock.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/security.h>
 #include <linux/module.h>
 #include <linux/syscalls.h>
@@ -252,7 +252,7 @@ ssize_t vfs_read(struct file *file, char
 			else
 				ret = do_sync_read(file, buf, count, pos);
 			if (ret > 0) {
-				dnotify_parent(file->f_dentry, DN_ACCESS);
+				fsnotify_access(file->f_dentry);
 				current->rchar += ret;
 			}
 			current->syscr++;
@@ -303,7 +303,7 @@ ssize_t vfs_write(struct file *file, con
 			else
 				ret = do_sync_write(file, buf, count, pos);
 			if (ret > 0) {
-				dnotify_parent(file->f_dentry, DN_MODIFY);
+				fsnotify_modify(file->f_dentry);
 				current->wchar += ret;
 			}
 			current->syscw++;
@@ -539,9 +539,12 @@ static ssize_t do_readv_writev(int type,
 out:
 	if (iov != iovstack)
 		kfree(iov);
-	if ((ret + (type == READ)) > 0)
-		dnotify_parent(file->f_dentry,
-				(type == READ) ? DN_ACCESS : DN_MODIFY);
+	if ((ret + (type == READ)) > 0) {
+		if (type == READ)
+			fsnotify_access(file->f_dentry);
+		else
+			fsnotify_modify(file->f_dentry);
+	}
 	return ret;
 Efault:
 	ret = -EFAULT;
Index: linux-2.6.13-rc2-fsnotify-2/fs/sysfs/file.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/sysfs/file.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/sysfs/file.c
@@ -3,7 +3,7 @@
  */
 
 #include <linux/module.h>
-#include <linux/dnotify.h>
+#include <linux/fsnotify.h>
 #include <linux/kobject.h>
 #include <linux/namei.h>
 #include <asm/uaccess.h>
@@ -391,9 +391,6 @@ int sysfs_create_file(struct kobject * k
  * sysfs_update_file - update the modified timestamp on an object attribute.
  * @kobj: object we're acting for.
  * @attr: attribute descriptor.
- *
- * Also call dnotify for the dentry, which lots of userspace programs
- * use.
  */
 int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
 {
@@ -408,7 +405,7 @@ int sysfs_update_file(struct kobject * k
 		if (victim->d_inode && 
 		    (victim->d_parent->d_inode == dir->d_inode)) {
 			victim->d_inode->i_mtime = CURRENT_TIME;
-			dnotify_parent(victim, DN_MODIFY);
+			fsnotify_modify(victim);
 
 			/**
 			 * Drop reference from initial sysfs_get_dentry().
Index: linux-2.6.13-rc2-fsnotify-2/fs/xattr.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/xattr.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/xattr.c
@@ -16,6 +16,7 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/module.h>
+#include <linux/fsnotify.h>
 #include <asm/uaccess.h>
 
 /*
@@ -57,8 +58,10 @@ setxattr(struct dentry *d, char __user *
 		if (error)
 			goto out;
 		error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
-		if (!error)
+		if (!error) {
+			fsnotify_xattr(d);
 			security_inode_post_setxattr(d, kname, kvalue, size, flags);
+		}
 out:
 		up(&d->d_inode->i_sem);
 	}
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/fs.h
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/include/linux/fs.h
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/fs.h
@@ -1393,7 +1393,6 @@ extern void emergency_remount(void);
 extern int do_remount_sb(struct super_block *sb, int flags,
 			 void *data, int force);
 extern sector_t bmap(struct inode *, sector_t);
-extern int setattr_mask(unsigned int);
 extern int notify_change(struct dentry *, struct iattr *);
 extern int permission(struct inode *, int, struct nameidata *);
 extern int generic_permission(struct inode *, int,
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/fsnotify.h
===================================================================
--- /dev/null
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/fsnotify.h
@@ -0,0 +1,118 @@
+#ifndef _LINUX_FS_NOTIFY_H
+#define _LINUX_FS_NOTIFY_H
+
+/*
+ * include/linux/fsnotify.h - generic hooks for filesystem notification, to
+ * reduce in-source duplication from both dnotify and inotify.
+ *
+ * We don't compile any of this away in some complicated menagerie of ifdefs.
+ * Instead, we rely on the code inside to optimize away as needed.
+ *
+ * (C) Copyright 2005 Robert Love
+ */
+
+#ifdef __KERNEL__
+
+#include <linux/dnotify.h>
+
+/*
+ * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
+ */
+static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
+				 const char *old_name, const char *new_name,
+				 int isdir)
+{
+	dnotify_move(old_dir, new_dir, old_name, new_name, isdir);
+}
+
+/*
+ * fsnotify_unlink - file was unlinked
+ */
+static inline void fsnotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+	dnotify_unlink(dentry, dir);
+}
+
+/*
+ * fsnotify_rmdir - directory was removed
+ */
+static inline void fsnotify_rmdir(struct dentry *dentry, struct inode *inode,
+				  struct inode *dir)
+{
+	dnotify_rmdir(dentry, inode, dir);
+}
+
+/*
+ * fsnotify_create - 'name' was linked in
+ */
+static inline void fsnotify_create(struct inode *inode, const char *name)
+{
+	dnotify_create(inode, name);
+}
+
+/*
+ * fsnotify_mkdir - directory 'name' was created
+ */
+static inline void fsnotify_mkdir(struct inode *inode, const char *name)
+{
+	dnotify_mkdir(inode, name);
+}
+
+/*
+ * fsnotify_access - file was read
+ */
+static inline void fsnotify_access(struct dentry *dentry)
+{
+	dnotify_access(dentry);
+}
+
+/*
+ * fsnotify_modify - file was modified
+ */
+static inline void fsnotify_modify(struct dentry *dentry)
+{
+	dnotify_modify(dentry);
+}
+
+/*
+ * fsnotify_open - file was opened
+ */
+static inline void fsnotify_open(struct dentry *dentry)
+{
+}
+
+/*
+ * fsnotify_close - file was closed
+ */
+static inline void fsnotify_close(struct file *file)
+{
+}
+
+/*
+ * fsnotify_xattr - extended attributes were changed
+ */
+static inline void fsnotify_xattr(struct dentry *dentry)
+{
+}
+
+/*
+ * fsnotify_change - notify_change event.  file was modified and/or metadata
+ * was changed.
+ */
+static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
+{
+	dnotify_change(dentry, ia_valid);
+}
+
+static inline const char *fsnotify_oldname_init(const char *name)
+{
+	return NULL;
+}
+
+static inline void fsnotify_oldname_free(const char *old_name)
+{
+}
+
+#endif	/* __KERNEL__ */
+
+#endif	/* _LINUX_FS_NOTIFY_H */
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/dnotify.h
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/include/linux/dnotify.h
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/dnotify.h
@@ -33,8 +33,109 @@ static inline void inode_dir_notify(stru
 		__inode_dir_notify(inode, event);
 }
 
+static inline void dnotify_move(struct inode *old_dir, struct inode *new_dir,
+				 const char *old_name, const char *new_name,
+				 int isdir)
+{
+	if (old_dir == new_dir)
+		inode_dir_notify(old_dir, DN_RENAME);
+	else {
+		inode_dir_notify(old_dir, DN_DELETE);
+		inode_dir_notify(new_dir, DN_CREATE);
+	}
+}
+
+static inline void dnotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+	inode_dir_notify(dir, DN_DELETE);
+}
+
+static inline void dnotify_rmdir(struct dentry *dentry, struct inode *inode,
+				  struct inode *dir)
+{
+	inode_dir_notify(dir, DN_DELETE);
+}
+
+static inline void dnotify_create(struct inode *inode, const char *name)
+{
+	inode_dir_notify(inode, DN_CREATE);
+}
+
+static inline void dnotify_mkdir(struct inode *inode, const char *name)
+{
+	inode_dir_notify(inode, DN_CREATE);
+}
+
+static inline void dnotify_access(struct dentry *dentry)
+{
+	dnotify_parent(dentry, DN_ACCESS);
+}
+
+static inline void dnotify_modify(struct dentry *dentry)
+{
+	dnotify_parent(dentry, DN_MODIFY);
+}
+
+static inline void dnotify_change(struct dentry *dentry, unsigned int ia_valid)
+{
+	int dn_mask = 0;
+
+	if (ia_valid & ATTR_UID)
+		dn_mask |= DN_ATTRIB;
+	if (ia_valid & ATTR_GID)
+		dn_mask |= DN_ATTRIB;
+	if (ia_valid & ATTR_SIZE)
+		dn_mask |= DN_MODIFY;
+	/* both times implies a utime(s) call */
+	if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
+		dn_mask |= DN_ATTRIB;
+	else if (ia_valid & ATTR_ATIME)
+		dn_mask |= DN_ACCESS;
+	else if (ia_valid & ATTR_MTIME)
+		dn_mask |= DN_MODIFY;
+	if (ia_valid & ATTR_MODE)
+		dn_mask |= DN_ATTRIB;
+
+	if (dn_mask)
+		dnotify_parent(dentry, dn_mask);
+}
 #else
 
+static inline void dnotify_move(struct inode *old_dir, struct inode *new_dir,
+				 const char *old_name, const char *new_name,
+				 int isdir)
+{
+}
+
+static inline void dnotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+}
+
+static inline void dnotify_rmdir(struct dentry *dentry, struct inode *inode,
+				  struct inode *dir)
+{
+}
+
+static inline void dnotify_create(struct inode *inode, const char *name)
+{
+}
+
+static inline void dnotify_mkdir(struct inode *inode, const char *name)
+{
+}
+
+static inline void dnotify_access(struct dentry *dentry)
+{
+}
+
+static inline void dnotify_modify(struct dentry *dentry)
+{
+}
+
+static inline void dnotify_change(struct dentry *dentry, unsigned int ia_valid)
+{
+}
+
 static inline void __inode_dir_notify(struct inode *inode, unsigned long event)
 {
 }

[RFC/PATCH 2/2] inotify

[Chris Wright]

inotify

 Documentation/filesystems/inotify.txt |  155 +++++
 fs/Kconfig                            |   13 
 fs/Makefile                           |    1 
 fs/inode.c                            |    6 
 fs/inotify.c                          | 1011 ++++++++++++++++++++++++++++++++++
 include/linux/fs.h                    |    5 
 include/linux/fsnotify.h              |   34 +
 include/linux/inotify.h               |  301 ++++++++++
 include/linux/sched.h                 |    4 
 kernel/user.c                         |    4 
 10 files changed, 1534 insertions(+)

Index: linux-2.6.13-rc2-fsnotify-2/Documentation/filesystems/inotify.txt
===================================================================
--- /dev/null
+++ linux-2.6.13-rc2-fsnotify-2/Documentation/filesystems/inotify.txt
@@ -0,0 +1,155 @@
+				    inotify
+	     a powerful yet simple file change notification system
+
+
+
+Document started 15 Mar 2005 by Robert Love <rml@novell.com>
+
+(i) User Interface
+
+Inotify is controlled by a device node, /dev/inotify.  If you do not use udev,
+this device may need to be created manually.
+
+First step in using inotify is to open the device file:
+
+	int dev_fd = open ("/dev/inotify", O_RDONLY);
+
+Change events are managed by "watches".  A watch is an (object,mask) pair where
+the object is a file or directory and the mask is a bitmask of one or more
+inotify events that the application wishes to receive.  See <linux/inotify.h>
+for valid events.  A watch is referenced by a watch descriptor, or wd.
+
+Watches are added via a file descriptor to the file.
+
+Watches on a directory will return events on any files inside of the directory.
+
+Adding a watch is simple,
+
+	/* 'wd' represents the watch on fd with mask */
+	struct inotify_request req = { fd, mask };
+	int wd = ioctl (dev_fd, INOTIFY_WATCH, &req);
+
+You can add a large number of files via something like
+
+	for each file to watch {
+		struct inotify_request req;
+		int file_fd;
+
+		file_fd = open (file, O_RDONLY);
+		if (fd < 0) {
+			perror ("open");
+			break;
+		}
+
+		req.fd = file_fd;
+		req.mask = mask;
+
+		wd = ioctl (dev_fd, INOTIFY_WATCH, &req);
+
+		close (fd);
+	}
+
+You can update an existing watch in the same manner, by passing in a new mask.
+
+An existing watch is removed via the INOTIFY_IGNORE ioctl, for example
+
+	ioctl (dev_fd, INOTIFY_IGNORE, wd);
+
+Events are provided in the form of an inotify_event structure that is read(2)
+from /dev/inotify.  The filename is of dynamic length and follows the struct.
+It is of size len.  The filename is padded with null bytes to ensure proper
+alignment.  This padding is reflected in len.
+
+You can slurp multiple events by passing a large buffer, for example
+
+	size_t len = read (fd, buf, BUF_LEN);
+
+Will return as many events as are available and fit in BUF_LEN.
+
+/dev/inotify is also select()- and poll()-able.
+
+You can find the size of the current event queue via the FIONREAD ioctl.
+
+All watches are destroyed and cleaned up on close.
+
+
+(ii) Internal Kernel Implementation
+
+Each open inotify device is associated with an inotify_device structure.
+
+Each watch is associated with an inotify_watch structure.  Watches are chained
+off of each associated device and each associated inode.
+
+See fs/inotify.c for the locking and lifetime rules.
+
+
+(iii) Rationale
+
+Q: What is the design decision behind not tying the watch to the open fd of
+   the watched object?
+
+A: Watches are associated with an open inotify device, not an open file.
+   This solves the primary problem with dnotify: keeping the file open pins
+   the file and thus, worse, pins the mount.  Dnotify is therefore infeasible
+   for use on a desktop system with removable media as the media cannot be
+   unmounted.
+
+Q: What is the design decision behind using an-fd-per-device as opposed to
+   an fd-per-watch?
+
+A: An fd-per-watch quickly consumes more file descriptors than are allowed,
+   more fd's than are feasible to manage, and more fd's than are optimally
+   select()-able.  Yes, root can bump the per-process fd limit and yes, users
+   can use epoll, but requiring both is a silly and extraneous requirement.
+   A watch consumes less memory than an open file, separating the number
+   spaces is thus sensible.  The current design is what user-space developers
+   want: Users open the device, once, and add n watches, requiring but one fd
+   and no twiddling with fd limits.  Opening /dev/inotify two thousand times
+   is silly.  If we can implement user-space's preferences cleanly--and we
+   can, the idr layer makes stuff like this trivial--then we should.
+
+   There are other good arguments.  With a single fd, there is a single
+   item to block on, which is mapped to a single queue of events.  The single
+   fd returns all watch events and also any potential out-of-band data.  If
+   every fd was a separate watch,
+
+   - There would be no way to get event ordering.  Events on file foo and
+     file bar would pop poll() on both fd's, but there would be no way to tell
+     which happened first.  A single queue trivially gives you ordering.  Such
+     ordering is crucial to existing applications such as Beagle.  Imagine
+     "mv a b ; mv b a" events without ordering.
+
+   - We'd have to maintain n fd's and n internal queues with state,
+     versus just one.  It is a lot messier in the kernel.  A single, linear
+     queue is the data structure that makes sense.
+
+   - User-space developers prefer the current API.  The Beagle guys, for
+     example, love it.  Trust me, I asked.  It is not a surprise: Who'd want
+     to manage and block on 1000 fd's via select?
+
+   - You'd have to manage the fd's, as an example: Call close() when you
+     received a delete event.
+
+   - No way to get out of band data.
+
+   - 1024 is still too low.  ;-)
+
+   When you talk about designing a file change notification system that
+   scales to 1000s of directories, juggling 1000s of fd's just does not seem
+   the right interface.  It is too heavy.
+
+Q: Why a device node?
+
+A: The poor user-space interface is the second biggest problem with dnotify.
+   Signals are a terrible, terrible interface for file notification.  Or for
+   anything, for that matter.  The idea solution, from all perspectives, is a
+   file descriptor-based one that allows basic file I/O and poll/select.
+   Obtaining the fd and managing the watches could have been done either via a
+   device file or a family of new system calls.  We decided to implement a
+   device file because adding three or four new system calls that mirrored
+   open, close, and ioctl seemed silly.  A character device makes sense from
+   user-space and was easy to implement inside of the kernel.
+
+   Additionally, it _is_ possible to open /dev/inotify more than once and
+   juggle more than one queue and thus more than one associated fd.
+
Index: linux-2.6.13-rc2-fsnotify-2/fs/inode.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/inode.c
+++ linux-2.6.13-rc2-fsnotify-2/fs/inode.c
@@ -21,6 +21,7 @@
 #include <linux/pagemap.h>
 #include <linux/cdev.h>
 #include <linux/bootmem.h>
+#include <linux/inotify.h>
 
 /*
  * This is needed for the following functions:
@@ -202,6 +203,10 @@ void inode_init_once(struct inode *inode
 	INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
 	spin_lock_init(&inode->i_lock);
 	i_size_ordered_init(inode);
+#ifdef CONFIG_INOTIFY
+	INIT_LIST_HEAD(&inode->inotify_watches);
+	sema_init(&inode->inotify_sem, 1);
+#endif
 }
 
 EXPORT_SYMBOL(inode_init_once);
@@ -346,6 +351,7 @@ int invalidate_inodes(struct super_block
 
 	down(&iprune_sem);
 	spin_lock(&inode_lock);
+	inotify_unmount_inodes(&sb->s_inodes);
 	busy = invalidate_list(&sb->s_inodes, &throw_away);
 	spin_unlock(&inode_lock);
 
Index: linux-2.6.13-rc2-fsnotify-2/fs/inotify.c
===================================================================
--- /dev/null
+++ linux-2.6.13-rc2-fsnotify-2/fs/inotify.c
@@ -0,0 +1,1011 @@
+/*
+ * fs/inotify.c - inode-based file event notifications
+ *
+ * Authors:
+ *	John McCutchan	<ttb@tentacle.dhs.org>
+ *	Robert Love	<rml@novell.com>
+ *
+ * Copyright (C) 2005 John McCutchan
+ *
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/poll.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/writeback.h>
+#include <linux/inotify.h>
+
+#include <asm/ioctls.h>
+
+static atomic_t inotify_cookie;
+
+static kmem_cache_t *watch_cachep;
+static kmem_cache_t *event_cachep;
+
+static int max_user_devices;
+static int max_user_watches;
+static unsigned int max_queued_events;
+
+/*
+ * Lock ordering:
+ *
+ * dentry->d_lock (used to keep d_move() away from dentry->d_parent)
+ * iprune_sem (synchronize shrink_icache_memory())
+ * 	inode_lock (protects the super_block->s_inodes list)
+ * 	inode->inotify_sem (protects inode->inotify_watches and watches->i_list)
+ * 		inotify_dev->sem (protects inotify_device and watches->d_list)
+ */
+
+/*
+ * Lifetimes of the three main data structures--inotify_device, inode, and
+ * inotify_watch--are managed by reference count.
+ *
+ * inotify_device: Lifetime is from open until release.  Additional references
+ * can bump the count via get_inotify_dev() and drop the count via
+ * put_inotify_dev().
+ *
+ * inotify_watch: Lifetime is from create_watch() to destory_watch().
+ * Additional references can bump the count via get_inotify_watch() and drop
+ * the count via put_inotify_watch().
+ *
+ * inode: Pinned so long as the inode is associated with a watch, from
+ * create_watch() to put_inotify_watch().
+ */
+
+/*
+ * struct inotify_device - represents an open instance of an inotify device
+ *
+ * This structure is protected by the semaphore 'sem'.
+ */
+struct inotify_device {
+	wait_queue_head_t 	wq;		/* wait queue for i/o */
+	struct idr		idr;		/* idr mapping wd -> watch */
+	struct semaphore	sem;		/* protects this bad boy */
+	struct list_head 	events;		/* list of queued events */
+	struct list_head	watches;	/* list of watches */
+	atomic_t		count;		/* reference count */
+	struct user_struct	*user;		/* user who opened this dev */
+	unsigned int		queue_size;	/* size of the queue (bytes) */
+	unsigned int		event_count;	/* number of pending events */
+	unsigned int		max_events;	/* maximum number of events */
+};
+
+/*
+ * struct inotify_kernel_event - An inotify event, originating from a watch and
+ * queued for user-space.  A list of these is attached to each instance of the
+ * device.  In read(), this list is walked and all events that can fit in the
+ * buffer are returned.
+ *
+ * Protected by dev->sem of the device in which we are queued.
+ */
+struct inotify_kernel_event {
+	struct inotify_event	event;	/* the user-space event */
+	struct list_head        list;	/* entry in inotify_device's list */
+	char			*name;	/* filename, if any */
+};
+
+/*
+ * struct inotify_watch - represents a watch request on a specific inode
+ *
+ * d_list is protected by dev->sem of the associated watch->dev.
+ * i_list and mask are protected by inode->inotify_sem of the associated inode.
+ * dev, inode, and wd are never written to once the watch is created.
+ */
+struct inotify_watch {
+	struct list_head	d_list;	/* entry in inotify_device's list */
+	struct list_head	i_list;	/* entry in inode's list */
+	atomic_t		count;	/* reference count */
+	struct inotify_device	*dev;	/* associated device */
+	struct inode		*inode;	/* associated inode */
+	s32 			wd;	/* watch descriptor */
+	u32			mask;	/* event mask for this watch */
+};
+
+static ssize_t show_max_queued_events(struct class_device *class, char *buf)
+{
+	return sprintf(buf, "%d\n", max_queued_events);
+}
+
+static ssize_t store_max_queued_events(struct class_device *class,
+				       const char *buf, size_t count)
+{
+	unsigned int max;
+
+	if (sscanf(buf, "%u", &max) > 0 && max > 0) {
+		max_queued_events = max;
+		return strlen(buf);
+	}
+	return -EINVAL;
+}
+
+static ssize_t show_max_user_devices(struct class_device *class, char *buf)
+{
+	return sprintf(buf, "%d\n", max_user_devices);
+}
+
+static ssize_t store_max_user_devices(struct class_device *class,
+				      const char *buf, size_t count)
+{
+	int max;
+
+	if (sscanf(buf, "%d", &max) > 0 && max > 0) {
+		max_user_devices = max;
+		return strlen(buf);
+	}
+	return -EINVAL;
+}
+
+static ssize_t show_max_user_watches(struct class_device *class, char *buf)
+{
+	return sprintf(buf, "%d\n", max_user_watches);
+}
+
+static ssize_t store_max_user_watches(struct class_device *class,
+				      const char *buf, size_t count)
+{
+	int max;
+
+	if (sscanf(buf, "%d", &max) > 0 && max > 0) {
+		max_user_watches = max;
+		return strlen(buf);
+	}
+	return -EINVAL;
+}
+
+static CLASS_DEVICE_ATTR(max_queued_events, S_IRUGO | S_IWUSR,
+			 show_max_queued_events, store_max_queued_events);
+static CLASS_DEVICE_ATTR(max_user_devices, S_IRUGO | S_IWUSR,
+			 show_max_user_devices, store_max_user_devices);
+static CLASS_DEVICE_ATTR(max_user_watches, S_IRUGO | S_IWUSR,
+			 show_max_user_watches, store_max_user_watches);
+
+static inline void get_inotify_dev(struct inotify_device *dev)
+{
+	atomic_inc(&dev->count);
+}
+
+static inline void put_inotify_dev(struct inotify_device *dev)
+{
+	if (atomic_dec_and_test(&dev->count)) {
+		atomic_dec(&dev->user->inotify_devs);
+		free_uid(dev->user);
+		kfree(dev);
+	}
+}
+
+static inline void get_inotify_watch(struct inotify_watch *watch)
+{
+	atomic_inc(&watch->count);
+}
+
+/*
+ * put_inotify_watch - decrements the ref count on a given watch.  cleans up
+ * the watch and its references if the count reaches zero.
+ */
+static inline void put_inotify_watch(struct inotify_watch *watch)
+{
+	if (atomic_dec_and_test(&watch->count)) {
+		put_inotify_dev(watch->dev);
+		iput(watch->inode);
+		kmem_cache_free(watch_cachep, watch);
+	}
+}
+
+/*
+ * kernel_event - create a new kernel event with the given parameters
+ *
+ * This function can sleep.
+ */
+static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
+						  const char *name)
+{
+	struct inotify_kernel_event *kevent;
+
+	kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL);
+	if (unlikely(!kevent))
+		return NULL;
+
+	/* we hand this out to user-space, so zero it just in case */
+	memset(&kevent->event, 0, sizeof(struct inotify_event));
+
+	kevent->event.wd = wd;
+	kevent->event.mask = mask;
+	kevent->event.cookie = cookie;
+
+	INIT_LIST_HEAD(&kevent->list);
+
+	if (name) {
+		size_t len, rem, event_size = sizeof(struct inotify_event);
+
+		/*
+		 * We need to pad the filename so as to properly align an
+		 * array of inotify_event structures.  Because the structure is
+		 * small and the common case is a small filename, we just round
+		 * up to the next multiple of the structure's sizeof.  This is
+		 * simple and safe for all architectures.
+		 */
+		len = strlen(name) + 1;
+		rem = event_size - len;
+		if (len > event_size) {
+			rem = event_size - (len % event_size);
+			if (len % event_size == 0)
+				rem = 0;
+		}
+
+		kevent->name = kmalloc(len + rem, GFP_KERNEL);
+		if (unlikely(!kevent->name)) {
+			kmem_cache_free(event_cachep, kevent);
+			return NULL;
+		}
+		memcpy(kevent->name, name, len);
+		if (rem)
+			memset(kevent->name + len, 0, rem);
+		kevent->event.len = len + rem;
+	} else {
+		kevent->event.len = 0;
+		kevent->name = NULL;
+	}
+
+	return kevent;
+}
+
+/*
+ * inotify_dev_get_event - return the next event in the given dev's queue
+ *
+ * Caller must hold dev->sem.
+ */
+static inline struct inotify_kernel_event *
+inotify_dev_get_event(struct inotify_device *dev)
+{
+	return list_entry(dev->events.next, struct inotify_kernel_event, list);
+}
+
+/*
+ * inotify_dev_queue_event - add a new event to the given device
+ *
+ * Caller must hold dev->sem.  Can sleep (calls kernel_event()).
+ */
+static void inotify_dev_queue_event(struct inotify_device *dev,
+				    struct inotify_watch *watch, u32 mask,
+				    u32 cookie, const char *name)
+{
+	struct inotify_kernel_event *kevent, *last;
+
+	/* coalescing: drop this event if it is a dupe of the previous */
+	last = inotify_dev_get_event(dev);
+	if (last && last->event.mask == mask && last->event.wd == watch->wd &&
+			last->event.cookie == cookie) {
+		const char *lastname = last->name;
+
+		if (!name && !lastname)
+			return;
+		if (name && lastname && !strcmp(lastname, name))
+			return;
+	}
+
+	/* the queue overflowed and we already sent the Q_OVERFLOW event */
+	if (unlikely(dev->event_count > dev->max_events))
+		return;
+
+	/* if the queue overflows, we need to notify user space */
+	if (unlikely(dev->event_count == dev->max_events))
+		kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL);
+	else
+		kevent = kernel_event(watch->wd, mask, cookie, name);
+
+	if (unlikely(!kevent))
+		return;
+
+	/* queue the event and wake up anyone waiting */
+	dev->event_count++;
+	dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
+	list_add_tail(&kevent->list, &dev->events);
+	wake_up_interruptible(&dev->wq);
+}
+
+/*
+ * remove_kevent - cleans up and ultimately frees the given kevent
+ *
+ * Caller must hold dev->sem.
+ */
+static void remove_kevent(struct inotify_device *dev,
+			  struct inotify_kernel_event *kevent)
+{
+	list_del(&kevent->list);
+
+	dev->event_count--;
+	dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len;
+
+	kfree(kevent->name);
+	kmem_cache_free(event_cachep, kevent);
+}
+
+/*
+ * inotify_dev_event_dequeue - destroy an event on the given device
+ *
+ * Caller must hold dev->sem.
+ */
+static void inotify_dev_event_dequeue(struct inotify_device *dev)
+{
+	if (!list_empty(&dev->events)) {
+		struct inotify_kernel_event *kevent;
+		kevent = inotify_dev_get_event(dev);
+		remove_kevent(dev, kevent);
+	}
+}
+
+/*
+ * inotify_dev_get_wd - returns the next WD for use by the given dev
+ *
+ * Callers must hold dev->sem.  This function can sleep.
+ */
+static int inotify_dev_get_wd(struct inotify_device *dev,
+			      struct inotify_watch *watch)
+{
+	int ret;
+
+	do {
+		if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL)))
+			return -ENOSPC;
+		ret = idr_get_new(&dev->idr, watch, &watch->wd);
+	} while (ret == -EAGAIN);
+
+	return ret;
+}
+
+/*
+ * create_watch - creates a watch on the given device.
+ *
+ * Callers must hold dev->sem.  Calls inotify_dev_get_wd() so may sleep.
+ * Both 'dev' and 'inode' (by way of nameidata) need to be pinned.
+ */
+static struct inotify_watch *create_watch(struct inotify_device *dev,
+					  u32 mask, struct inode *inode)
+{
+	struct inotify_watch *watch;
+	int ret;
+
+	if (atomic_read(&dev->user->inotify_watches) >= max_user_watches)
+		return ERR_PTR(-ENOSPC);
+
+	watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
+	if (unlikely(!watch))
+		return ERR_PTR(-ENOMEM);
+
+	ret = inotify_dev_get_wd(dev, watch);
+	if (unlikely(ret)) {
+		kmem_cache_free(watch_cachep, watch);
+		return ERR_PTR(ret);
+	}
+
+	watch->mask = mask;
+	atomic_set(&watch->count, 0);
+	INIT_LIST_HEAD(&watch->d_list);
+	INIT_LIST_HEAD(&watch->i_list);
+
+	/* save a reference to device and bump the count to make it official */
+	get_inotify_dev(dev);
+	watch->dev = dev;
+
+	/*
+	 * Save a reference to the inode and bump the ref count to make it
+	 * official.  We hold a reference to nameidata, which makes this safe.
+	 */
+	watch->inode = igrab(inode);
+
+	/* bump our own count, corresponding to our entry in dev->watches */
+	get_inotify_watch(watch);
+
+	atomic_inc(&dev->user->inotify_watches);
+
+	return watch;
+}
+
+/*
+ * inotify_find_dev - find the watch associated with the given inode and dev
+ *
+ * Callers must hold inode->inotify_sem.
+ */
+static struct inotify_watch *inode_find_dev(struct inode *inode,
+					    struct inotify_device *dev)
+{
+	struct inotify_watch *watch;
+
+	list_for_each_entry(watch, &inode->inotify_watches, i_list) {
+		if (watch->dev == dev)
+			return watch;
+	}
+
+	return NULL;
+}
+
+/*
+ * remove_watch_no_event - remove_watch() without the IN_IGNORED event.
+ */
+static void remove_watch_no_event(struct inotify_watch *watch,
+				  struct inotify_device *dev)
+{
+	list_del(&watch->i_list);
+	list_del(&watch->d_list);
+
+	atomic_dec(&dev->user->inotify_watches);
+	idr_remove(&dev->idr, watch->wd);
+	put_inotify_watch(watch);
+}
+
+/*
+ * remove_watch - Remove a watch from both the device and the inode.  Sends
+ * the IN_IGNORED event to the given device signifying that the inode is no
+ * longer watched.
+ *
+ * Callers must hold both inode->inotify_sem and dev->sem.  We drop a
+ * reference to the inode before returning.
+ *
+ * The inode is not iput() so as to remain atomic.  If the inode needs to be
+ * iput(), the call returns one.  Otherwise, it returns zero.
+ */
+static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev)
+{
+	inotify_dev_queue_event(dev, watch, IN_IGNORED, 0, NULL);
+	remove_watch_no_event(watch, dev);
+}
+
+/*
+ * inotify_inode_watched - returns nonzero if there are watches on this inode
+ * and zero otherwise.  We call this lockless, we do not care if we race.
+ */
+static inline int inotify_inode_watched(struct inode *inode)
+{
+	return !list_empty(&inode->inotify_watches);
+}
+
+/* Kernel API */
+
+/**
+ * inotify_inode_queue_event - queue an event to all watches on this inode
+ * @inode: inode event is originating from
+ * @mask: event mask describing this event
+ * @cookie: cookie for synchronization, or zero
+ * @name: filename, if any
+ */
+void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie,
+			       const char *name)
+{
+	struct inotify_watch *watch, *next;
+
+	if (!inotify_inode_watched(inode))
+		return;
+
+	down(&inode->inotify_sem);
+	list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) {
+		u32 watch_mask = watch->mask;
+		if (watch_mask & mask) {
+			struct inotify_device *dev = watch->dev;
+			get_inotify_watch(watch);
+			down(&dev->sem);
+			inotify_dev_queue_event(dev, watch, mask, cookie, name);
+			if (watch_mask & IN_ONESHOT)
+				remove_watch_no_event(watch, dev);
+			up(&dev->sem);
+			put_inotify_watch(watch);
+		}
+	}
+	up(&inode->inotify_sem);
+}
+EXPORT_SYMBOL_GPL(inotify_inode_queue_event);
+
+/**
+ * inotify_dentry_parent_queue_event - queue an event to a dentry's parent
+ * @dentry: the dentry in question, we queue against this dentry's parent
+ * @mask: event mask describing this event
+ * @cookie: cookie for synchronization, or zero
+ * @name: filename, if any
+ */
+void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask,
+				       u32 cookie, const char *name)
+{
+	struct dentry *parent;
+	struct inode *inode;
+
+	spin_lock(&dentry->d_lock);
+	parent = dentry->d_parent;
+	inode = parent->d_inode;
+
+	if (inotify_inode_watched(inode)) {
+		dget(parent);
+		spin_unlock(&dentry->d_lock);
+		inotify_inode_queue_event(inode, mask, cookie, name);
+		dput(parent);
+	} else
+		spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event);
+
+/**
+ * inotify_get_cookie - return a unique cookie for use in synchronizing events.
+ */
+u32 inotify_get_cookie(void)
+{
+	return atomic_inc_return(&inotify_cookie);
+}
+EXPORT_SYMBOL_GPL(inotify_get_cookie);
+
+/**
+ * inotify_unmount_inodes - an sb is unmounting.  handle any watched inodes.
+ * @list: list of inodes being unmounted (sb->s_inodes)
+ *
+ * Called with inode_lock held, protecting the unmounting super block's list
+ * of inodes, and with iprune_sem held, keeping shrink_icache_memory() at bay.
+ * We temporarily drop inode_lock, however, and CAN block.
+ */
+void inotify_unmount_inodes(struct list_head *list)
+{
+	struct inode *inode, *next_i, *need_iput = NULL;
+
+	list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
+		struct inotify_watch *watch, *next_w;
+		struct inode *need_iput_tmp;
+		struct list_head *watches;
+
+		/*
+		 * If i_count is zero, the inode cannot have any watches and
+		 * doing an __iget/iput with MS_ACTIVE clear would actually
+		 * evict all inodes with zero i_count from icache which is
+		 * unnecessarily violent and may in fact be illegal to do.
+		 */
+		if (!atomic_read(&inode->i_count))
+			continue;
+
+		/*
+		 * We cannot __iget() an inode in state I_CLEAR, I_FREEING, or
+		 * I_WILL_FREE which is fine because by that point the inode
+		 * cannot have any associated watches.
+		 */
+		if (inode->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))
+			continue;
+
+		need_iput_tmp = need_iput;
+		need_iput = NULL;
+		/* In case the remove_watch() drops a reference. */
+		if (inode != need_iput_tmp)
+			__iget(inode);
+		else
+			need_iput_tmp = NULL;
+		/* In case the dropping of a reference would nuke next_i. */
+		if ((&next_i->i_sb_list != list) &&
+				atomic_read(&next_i->i_count) &&
+				!(next_i->i_state & (I_CLEAR | I_FREEING |
+					I_WILL_FREE))) {
+			__iget(next_i);
+			need_iput = next_i;
+		}
+
+		/*
+		 * We can safely drop inode_lock here because we hold
+		 * references on both inode and next_i.  Also no new inodes
+		 * will be added since the umount has begun.  Finally,
+		 * iprune_sem keeps shrink_icache_memory() away.
+		 */
+		spin_unlock(&inode_lock);
+
+		if (need_iput_tmp)
+			iput(need_iput_tmp);
+
+		/* for each watch, send IN_UNMOUNT and then remove it */
+		down(&inode->inotify_sem);
+		watches = &inode->inotify_watches;
+		list_for_each_entry_safe(watch, next_w, watches, i_list) {
+			struct inotify_device *dev = watch->dev;
+			down(&dev->sem);
+			inotify_dev_queue_event(dev, watch, IN_UNMOUNT,0,NULL);
+			remove_watch(watch, dev);
+			up(&dev->sem);
+		}
+		up(&inode->inotify_sem);
+		iput(inode);
+
+		spin_lock(&inode_lock);
+	}
+}
+EXPORT_SYMBOL_GPL(inotify_unmount_inodes);
+
+/**
+ * inotify_inode_is_dead - an inode has been deleted, cleanup any watches
+ * @inode: inode that is about to be removed
+ */
+void inotify_inode_is_dead(struct inode *inode)
+{
+	struct inotify_watch *watch, *next;
+
+	down(&inode->inotify_sem);
+	list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) {
+		struct inotify_device *dev = watch->dev;
+		down(&dev->sem);
+		remove_watch(watch, dev);
+		up(&dev->sem);
+	}
+	up(&inode->inotify_sem);
+}
+EXPORT_SYMBOL_GPL(inotify_inode_is_dead);
+
+/* Device Interface */
+
+static unsigned int inotify_poll(struct file *file, poll_table *wait)
+{
+	struct inotify_device *dev = file->private_data;
+	int ret = 0;
+
+	poll_wait(file, &dev->wq, wait);
+	down(&dev->sem);
+	if (!list_empty(&dev->events))
+		ret = POLLIN | POLLRDNORM;
+	up(&dev->sem);
+
+	return ret;
+}
+
+static ssize_t inotify_read(struct file *file, char __user *buf,
+			    size_t count, loff_t *pos)
+{
+	size_t event_size = sizeof (struct inotify_event);
+	struct inotify_device *dev;
+	char __user *start;
+	int ret;
+	DEFINE_WAIT(wait);
+
+	start = buf;
+	dev = file->private_data;
+
+	while (1) {
+		int events;
+
+		prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE);
+
+		down(&dev->sem);
+		events = !list_empty(&dev->events);
+		up(&dev->sem);
+		if (events) {
+			ret = 0;
+			break;
+		}
+
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		schedule();
+	}
+
+	finish_wait(&dev->wq, &wait);
+	if (ret)
+		return ret;
+
+	down(&dev->sem);
+	while (1) {
+		struct inotify_kernel_event *kevent;
+
+		ret = buf - start;
+		if (list_empty(&dev->events))
+			break;
+
+		kevent = inotify_dev_get_event(dev);
+		if (event_size + kevent->event.len > count)
+			break;
+
+		if (copy_to_user(buf, &kevent->event, event_size)) {
+			ret = -EFAULT;
+			break;
+		}
+		buf += event_size;
+		count -= event_size;
+
+		if (kevent->name) {
+			if (copy_to_user(buf, kevent->name, kevent->event.len)){
+				ret = -EFAULT;
+				break;
+			}
+			buf += kevent->event.len;
+			count -= kevent->event.len;
+		}
+
+		remove_kevent(dev, kevent);
+	}
+	up(&dev->sem);
+
+	return ret;
+}
+
+static int _inotify_open(struct inode *inode, struct file *file)
+{
+	struct inotify_device *dev;
+	struct user_struct *user;
+	int ret;
+
+	user = get_uid(current->user);
+
+	if (unlikely(atomic_read(&user->inotify_devs) >= max_user_devices)) {
+		ret = -EMFILE;
+		goto out_err;
+	}
+
+	dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
+	if (unlikely(!dev)) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	idr_init(&dev->idr);
+	INIT_LIST_HEAD(&dev->events);
+	INIT_LIST_HEAD(&dev->watches);
+	init_waitqueue_head(&dev->wq);
+	sema_init(&dev->sem, 1);
+	dev->event_count = 0;
+	dev->queue_size = 0;
+	dev->max_events = max_queued_events;
+	dev->user = user;
+	atomic_set(&dev->count, 0);
+
+	get_inotify_dev(dev);
+	atomic_inc(&user->inotify_devs);
+
+	file->private_data = dev;
+
+	ret = nonseekable_open(inode, file);
+	if (ret)
+		goto out_err;
+
+	return 0;
+out_err:
+	free_uid(user);
+	return ret;
+}
+
+static int inotify_release(struct inode *ignored, struct file *file)
+{
+	struct inotify_device *dev = file->private_data;
+
+	/*
+	 * Destroy all of the watches on this device.  Unfortunately, not very
+	 * pretty.  We cannot do a simple iteration over the list, because we
+	 * do not know the inode until we iterate to the watch.  But we need to
+	 * hold inode->inotify_sem before dev->sem.  The following works.
+	 */
+	while (1) {
+		struct inotify_watch *watch;
+		struct list_head *watches;
+		struct inode *inode;
+
+		down(&dev->sem);
+		watches = &dev->watches;
+		if (list_empty(watches)) {
+			up(&dev->sem);
+			break;
+		}
+		watch = list_entry(watches->next, struct inotify_watch, d_list);
+		get_inotify_watch(watch);
+		up(&dev->sem);
+
+		inode = watch->inode;
+		down(&inode->inotify_sem);
+		down(&dev->sem);
+		remove_watch_no_event(watch, dev);
+		up(&dev->sem);
+		up(&inode->inotify_sem);
+		put_inotify_watch(watch);
+	}
+
+	/* destroy all of the events on this device */
+	down(&dev->sem);
+	while (!list_empty(&dev->events))
+		inotify_dev_event_dequeue(dev);
+	up(&dev->sem);
+
+	/* free this device: the put matching the get in inotify_open() */
+	put_inotify_dev(dev);
+
+	return 0;
+}
+
+static int inotify_add_watch(struct inotify_device *dev, int fd, u32 mask)
+{
+	struct inotify_watch *watch, *old;
+	struct inode *inode;
+	struct file *filp;
+	int ret;
+
+	filp = fget(fd);
+	if (!filp)
+		return -EBADF;
+	inode = filp->f_dentry->d_inode;
+
+	down(&inode->inotify_sem);
+	down(&dev->sem);
+
+	/* don't let user-space set invalid bits: we don't want flags set */
+	mask &= IN_ALL_EVENTS;
+	if (!mask) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Handle the case of re-adding a watch on an (inode,dev) pair that we
+	 * are already watching.  We just update the mask and return its wd.
+	 */
+	old = inode_find_dev(inode, dev);
+	if (unlikely(old)) {
+		old->mask = mask;
+		ret = old->wd;
+		goto out;
+	}
+
+	watch = create_watch(dev, mask, inode);
+	if (unlikely(IS_ERR(watch))) {
+		ret = PTR_ERR(watch);
+		goto out;
+	}
+
+	/* Add the watch to the device's and the inode's list */
+	list_add(&watch->d_list, &dev->watches);
+	list_add(&watch->i_list, &inode->inotify_watches);
+	ret = watch->wd;
+
+out:
+	up(&dev->sem);
+	up(&inode->inotify_sem);
+	fput(filp);
+
+	return ret;
+}
+
+/*
+ * inotify_ignore - handle the INOTIFY_IGNORE ioctl, asking that a given wd be
+ * removed from the device.
+ *
+ * Can sleep.
+ */
+static int inotify_ignore(struct inotify_device *dev, s32 wd)
+{
+	struct inotify_watch *watch;
+	struct inode *inode;
+
+	down(&dev->sem);
+	watch = idr_find(&dev->idr, wd);
+	if (unlikely(!watch)) {
+		up(&dev->sem);
+		return -EINVAL;
+	}
+	get_inotify_watch(watch);
+	inode = watch->inode;
+	up(&dev->sem);
+
+	down(&inode->inotify_sem);
+	down(&dev->sem);
+
+	/* make sure that we did not race */
+	watch = idr_find(&dev->idr, wd);
+	if (likely(watch))
+		remove_watch(watch, dev);
+
+	up(&dev->sem);
+	up(&inode->inotify_sem);
+	put_inotify_watch(watch);
+
+	return 0;
+}
+
+static long inotify_ioctl(struct file *file, unsigned int cmd,
+			  unsigned long arg)
+{
+	struct inotify_device *dev;
+	struct inotify_watch_request request;
+	void __user *p;
+	int ret = -ENOTTY;
+	s32 wd;
+
+	dev = file->private_data;
+	p = (void __user *) arg;
+
+	switch (cmd) {
+	case INOTIFY_WATCH:
+		if (unlikely(copy_from_user(&request, p, sizeof (request)))) {
+			ret = -EFAULT;
+			break;
+		}
+		ret = inotify_add_watch(dev, request.fd, request.mask);
+		break;
+	case INOTIFY_IGNORE:
+		if (unlikely(get_user(wd, (int __user *) p))) {
+			ret = -EFAULT;
+			break;
+		}
+		ret = inotify_ignore(dev, wd);
+		break;
+	case FIONREAD:
+		ret = put_user(dev->queue_size, (int __user *) p);
+		break;
+	}
+
+	return ret;
+}
+
+static struct file_operations inotify_fops = {
+	.owner		= THIS_MODULE,
+	.poll		= inotify_poll,
+	.read		= inotify_read,
+	.open		= _inotify_open,
+	.release	= inotify_release,
+	.unlocked_ioctl	= inotify_ioctl,
+	.compat_ioctl	= inotify_ioctl,
+};
+
+static struct miscdevice inotify_device = {
+	.minor  = MISC_DYNAMIC_MINOR,
+	.name	= "inotify",
+	.fops	= &inotify_fops,
+};
+
+/*
+ * inotify_init - Our initialization function.  Note that we cannnot return
+ * error because we have compiled-in VFS hooks.  So an (unlikely) failure here
+ * must result in panic().
+ */
+static int __init inotify_init(void)
+{
+	struct class_device *class;
+	int ret;
+
+	ret = misc_register(&inotify_device);
+	if (unlikely(ret))
+		panic("inotify: misc_register returned %d\n", ret);
+
+	max_queued_events = 8192;
+	max_user_devices = 128;
+	max_user_watches = 8192;
+
+	class = inotify_device.class;
+	class_device_create_file(class, &class_device_attr_max_queued_events);
+	class_device_create_file(class, &class_device_attr_max_user_devices);
+	class_device_create_file(class, &class_device_attr_max_user_watches);
+
+	atomic_set(&inotify_cookie, 0);
+
+	watch_cachep = kmem_cache_create("inotify_watch_cache",
+					 sizeof(struct inotify_watch),
+					 0, SLAB_PANIC, NULL, NULL);
+	event_cachep = kmem_cache_create("inotify_event_cache",
+					 sizeof(struct inotify_kernel_event),
+					 0, SLAB_PANIC, NULL, NULL);
+
+	printk(KERN_INFO "inotify device minor=%d\n", inotify_device.minor);
+
+	return 0;
+}
+
+module_init(inotify_init);
Index: linux-2.6.13-rc2-fsnotify-2/fs/Kconfig
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/Kconfig
+++ linux-2.6.13-rc2-fsnotify-2/fs/Kconfig
@@ -356,6 +356,19 @@ config ROMFS_FS
 	  If you don't know whether you need it, then you don't need it:
 	  answer N.
 
+config INOTIFY
+	bool "Inotify file change notification support"
+	default y
+	---help---
+	  Say Y here to enable inotify support and the /dev/inotify character
+	  device.  Inotify is a file change notification system and a
+	  replacement for dnotify.  Inotify fixes numerous shortcomings in
+	  dnotify and introduces several new features.  It allows monitoring
+	  of both files and directories via a single open fd.  Multiple file
+	  events are supported.
+
+	  If unsure, say Y.
+
 config QUOTA
 	bool "Quota support"
 	help
Index: linux-2.6.13-rc2-fsnotify-2/fs/Makefile
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/fs/Makefile
+++ linux-2.6.13-rc2-fsnotify-2/fs/Makefile
@@ -12,6 +12,7 @@ obj-y :=	open.o read_write.o file_table.
 		seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
 		ioprio.o
 
+obj-$(CONFIG_INOTIFY)		+= inotify.o
 obj-$(CONFIG_EPOLL)		+= eventpoll.o
 obj-$(CONFIG_COMPAT)		+= compat.o
 
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/fs.h
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/include/linux/fs.h
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/fs.h
@@ -474,6 +474,11 @@ struct inode {
 	struct dnotify_struct	*i_dnotify; /* for directory notifications */
 #endif
 
+#ifdef CONFIG_INOTIFY
+	struct list_head	inotify_watches; /* watches on this inode */
+	struct semaphore	inotify_sem;	/* protects the watches list */
+#endif
+
 	unsigned long		i_state;
 	unsigned long		dirtied_when;	/* jiffies of first dirtying */
 
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/inotify.h
===================================================================
--- /dev/null
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/inotify.h
@@ -0,0 +1,301 @@
+/*
+ * Inode based directory notification for Linux
+ *
+ * Copyright (C) 2005 John McCutchan
+ */
+
+#ifndef _LINUX_INOTIFY_H
+#define _LINUX_INOTIFY_H
+
+#include <linux/types.h>
+
+/*
+ * struct inotify_event - structure read from the inotify device for each event
+ *
+ * When you are watching a directory, you will receive the filename for events
+ * such as IN_CREATE, IN_DELETE, IN_OPEN, IN_CLOSE, ..., relative to the wd.
+ */
+struct inotify_event {
+	__s32		wd;		/* watch descriptor */
+	__u32		mask;		/* watch mask */
+	__u32		cookie;		/* cookie to synchronize two events */
+	__u32		len;		/* length (including nulls) of name */
+	char		name[0];	/* stub for possible name */
+};
+
+/*
+ * struct inotify_watch_request - represents a watch request
+ *
+ * Pass to the inotify device via the INOTIFY_WATCH ioctl
+ */
+struct inotify_watch_request {
+	int		fd;		/* fd of filename to watch */
+	__u32		mask;		/* event mask */
+};
+
+/* the following are legal, implemented events that user-space can watch for */
+#define IN_ACCESS		0x00000001	/* File was accessed */
+#define IN_MODIFY		0x00000002	/* File was modified */
+#define IN_ATTRIB		0x00000004	/* Metadata changed */
+#define IN_CLOSE_WRITE		0x00000008	/* Writtable file was closed */
+#define IN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
+#define IN_OPEN			0x00000020	/* File was opened */
+#define IN_MOVED_FROM		0x00000040	/* File was moved from X */
+#define IN_MOVED_TO		0x00000080	/* File was moved to Y */
+#define IN_CREATE		0x00000100	/* Subfile was created */
+#define IN_DELETE		0x00000200	/* Subfile was deleted */
+#define IN_DELETE_SELF		0x00000400	/* Self was deleted */
+
+/* the following are legal events.  they are sent as needed to any watch */
+#define IN_UNMOUNT		0x00002000	/* Backing fs was unmounted */
+#define IN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
+#define IN_IGNORED		0x00008000	/* File was ignored */
+
+/* helper events */
+#define IN_CLOSE		(IN_CLOSE_WRITE | IN_CLOSE_NOWRITE) /* close */
+#define IN_MOVE			(IN_MOVED_FROM | IN_MOVED_TO) /* moves */
+
+/* special flags */
+#define IN_ISDIR		0x40000000	/* event occurred against dir */
+#define IN_ONESHOT		0x80000000	/* only send event once */
+
+/*
+ * All of the events - we build the list by hand so that we can add flags in
+ * the future and not break backward compatibility.  Apps will get only the
+ * events that they originally wanted.  Be sure to add new events here!
+ */
+#define IN_ALL_EVENTS	(IN_ACCESS | IN_MODIFY | IN_ATTRIB | IN_CLOSE_WRITE | \
+			 IN_CLOSE_NOWRITE | IN_OPEN | IN_MOVED_FROM | \
+			 IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF)
+
+#define INOTIFY_IOCTL_MAGIC	'Q'
+#define INOTIFY_IOCTL_MAXNR	2
+
+#define INOTIFY_WATCH  		_IOR(INOTIFY_IOCTL_MAGIC, 1, struct inotify_watch_request)
+#define INOTIFY_IGNORE 		_IOR(INOTIFY_IOCTL_MAGIC, 2, int)
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+#include <linux/fs.h>
+#include <linux/config.h>
+
+#ifdef CONFIG_INOTIFY
+
+extern void inotify_inode_queue_event(struct inode *, __u32, __u32,
+				      const char *);
+extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32,
+					      const char *);
+extern void inotify_unmount_inodes(struct list_head *);
+extern void inotify_inode_is_dead(struct inode *);
+extern u32 inotify_get_cookie(void);
+
+static inline void inotify_move(struct inode *old_dir, struct inode *new_dir,
+				const char *old_name, const char *new_name,
+				int isdir)
+{
+	u32 cookie = inotify_get_cookie();
+	if (isdir)
+		isdir = IN_ISDIR;
+	inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name);
+	inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name);
+}
+
+static inline void inotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+	struct inode *inode = dentry->d_inode;
+
+	inotify_inode_queue_event(dir, IN_DELETE, 0, dentry->d_name.name);
+	inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL);
+	inotify_inode_is_dead(inode);
+}
+
+static inline void inotify_rmdir(struct dentry *dentry, struct inode *inode,
+				 struct inode *dir)
+{
+	inotify_inode_queue_event(dir,IN_DELETE|IN_ISDIR,0,dentry->d_name.name);
+	inotify_inode_queue_event(inode, IN_DELETE_SELF | IN_ISDIR, 0, NULL);
+	inotify_inode_is_dead(inode);
+}
+
+static inline void inotify_create(struct inode *inode, const char *name)
+{
+	inotify_inode_queue_event(inode, IN_CREATE, 0, name);
+}
+
+static inline void inotify_mkdir(struct inode *inode, const char *name)
+{
+	inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, name);
+}
+
+static inline void inotify_access(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	u32 mask = IN_ACCESS;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= IN_ISDIR;
+
+	inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+	inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+static inline void inotify_modify(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	u32 mask = IN_MODIFY;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= IN_ISDIR;
+
+	inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+	inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+static inline void inotify_open(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	u32 mask = IN_OPEN;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= IN_ISDIR;
+
+	inotify_inode_queue_event(inode, mask, 0, NULL);
+	inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+}
+
+static inline void inotify_close(struct file *file)
+{
+	struct dentry *dentry = file->f_dentry;
+	struct inode *inode = dentry->d_inode;
+	const char *name = dentry->d_name.name;
+	mode_t mode = file->f_mode;
+	u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= IN_ISDIR;
+
+	inotify_dentry_parent_queue_event(dentry, mask, 0, name);
+	inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+static inline void inotify_xattr(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	u32 mask = IN_ATTRIB;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= IN_ISDIR;
+
+	inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+	inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+static inline void inotify_change(struct dentry *dentry, unsigned int ia_valid)
+{
+	struct inode *inode = dentry->d_inode;
+	u32 in_mask = 0;
+
+	if (ia_valid & ATTR_UID)
+		in_mask |= IN_ATTRIB;
+	if (ia_valid & ATTR_GID)
+		in_mask |= IN_ATTRIB;
+	if (ia_valid & ATTR_SIZE)
+		in_mask |= IN_MODIFY;
+	/* both times implies a utime(s) call */
+	if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
+		in_mask |= IN_ATTRIB;
+	else if (ia_valid & ATTR_ATIME)
+		in_mask |= IN_ACCESS;
+	else if (ia_valid & ATTR_MTIME)
+		in_mask |= IN_MODIFY;
+	if (ia_valid & ATTR_MODE)
+		in_mask |= IN_ATTRIB;
+	
+	if (in_mask) {
+		if (S_ISDIR(inode->i_mode))
+			in_mask |= IN_ISDIR;
+		inotify_inode_queue_event(inode, in_mask, 0, NULL);
+		inotify_dentry_parent_queue_event(dentry, in_mask, 0,
+						  dentry->d_name.name);
+	}
+}
+
+#else
+
+static inline void inotify_inode_queue_event(struct inode *inode,
+					     __u32 mask, __u32 cookie,
+					     const char *filename)
+{
+}
+
+static inline void inotify_dentry_parent_queue_event(struct dentry *dentry,
+						     __u32 mask, __u32 cookie,
+						     const char *filename)
+{
+}
+
+static inline void inotify_unmount_inodes(struct list_head *list)
+{
+}
+
+static inline void inotify_inode_is_dead(struct inode *inode)
+{
+}
+
+static inline u32 inotify_get_cookie(void)
+{
+	return 0;
+}
+
+static inline void inotify_move(struct inode *old_dir, struct inode *new_dir,
+				const char *old_name, const char *new_name,
+				int isdir)
+{
+}
+
+static inline void inotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+}
+
+static inline void inotify_rmdir(struct dentry *dentry, struct inode *inode,
+				 struct inode *dir)
+{
+}
+
+static inline void inotify_create(struct inode *inode, const char *name)
+{
+}
+
+static inline void inotify_mkdir(struct inode *inode, const char *name)
+{
+}
+
+static inline void inotify_access(struct dentry *dentry)
+{
+}
+
+static inline void inotify_modify(struct dentry *dentry)
+{
+}
+
+static inline void inotify_open(struct dentry *dentry)
+{
+}
+
+static inline void inotify_close(struct file *file)
+{
+}
+
+static inline void inotify_xattr(struct dentry *dentry)
+{
+}
+
+static inline void inotify_change(struct dentry *dentry, unsigned int ia_valid){
+{
+}
+#endif	/* CONFIG_INOTIFY */
+
+#endif	/* __KERNEL __ */
+
+#endif	/* _LINUX_INOTIFY_H */
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/sched.h
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/include/linux/sched.h
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/sched.h
@@ -410,6 +410,10 @@ struct user_struct {
 	atomic_t processes;	/* How many processes does this user have? */
 	atomic_t files;		/* How many open files does this user have? */
 	atomic_t sigpending;	/* How many pending signals does this user have? */
+#ifdef CONFIG_INOTIFY
+	atomic_t inotify_watches; /* How many inotify watches does this user have? */
+	atomic_t inotify_devs;	/* How many inotify devs does this user have opened? */
+#endif
 	/* protected by mq_lock	*/
 	unsigned long mq_bytes;	/* How many bytes can be allocated to mqueue? */
 	unsigned long locked_shm; /* How many pages of mlocked shm ? */
Index: linux-2.6.13-rc2-fsnotify-2/kernel/user.c
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/kernel/user.c
+++ linux-2.6.13-rc2-fsnotify-2/kernel/user.c
@@ -120,6 +120,10 @@ struct user_struct * alloc_uid(uid_t uid
 		atomic_set(&new->processes, 0);
 		atomic_set(&new->files, 0);
 		atomic_set(&new->sigpending, 0);
+#ifdef CONFIG_INOTIFY
+		atomic_set(&new->inotify_watches, 0);
+		atomic_set(&new->inotify_devs, 0);
+#endif
 
 		new->mq_bytes = 0;
 		new->locked_shm = 0;
Index: linux-2.6.13-rc2-fsnotify-2/include/linux/fsnotify.h
===================================================================
--- linux-2.6.13-rc2-fsnotify-2.orig/include/linux/fsnotify.h
+++ linux-2.6.13-rc2-fsnotify-2/include/linux/fsnotify.h
@@ -14,6 +14,7 @@
 #ifdef __KERNEL__
 
 #include <linux/dnotify.h>
+#include <linux/inotify.h>
 
 /*
  * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
@@ -23,6 +24,7 @@ static inline void fsnotify_move(struct 
 				 int isdir)
 {
 	dnotify_move(old_dir, new_dir, old_name, new_name, isdir);
+	inotify_move(old_dir, new_dir, old_name, new_name, isdir);
 }
 
 /*
@@ -31,6 +33,7 @@ static inline void fsnotify_move(struct 
 static inline void fsnotify_unlink(struct dentry *dentry, struct inode *dir)
 {
 	dnotify_unlink(dentry, dir);
+	inotify_unlink(dentry, dir);
 }
 
 /*
@@ -40,6 +43,7 @@ static inline void fsnotify_rmdir(struct
 				  struct inode *dir)
 {
 	dnotify_rmdir(dentry, inode, dir);
+	inotify_rmdir(dentry, inode, dir);
 }
 
 /*
@@ -48,6 +52,7 @@ static inline void fsnotify_rmdir(struct
 static inline void fsnotify_create(struct inode *inode, const char *name)
 {
 	dnotify_create(inode, name);
+	inotify_create(inode, name);
 }
 
 /*
@@ -56,6 +61,7 @@ static inline void fsnotify_create(struc
 static inline void fsnotify_mkdir(struct inode *inode, const char *name)
 {
 	dnotify_mkdir(inode, name);
+	inotify_mkdir(inode, name);
 }
 
 /*
@@ -64,6 +70,7 @@ static inline void fsnotify_mkdir(struct
 static inline void fsnotify_access(struct dentry *dentry)
 {
 	dnotify_access(dentry);
+	inotify_access(dentry);
 }
 
 /*
@@ -72,6 +79,7 @@ static inline void fsnotify_access(struc
 static inline void fsnotify_modify(struct dentry *dentry)
 {
 	dnotify_modify(dentry);
+	inotify_modify(dentry);
 }
 
 /*
@@ -79,6 +87,7 @@ static inline void fsnotify_modify(struc
  */
 static inline void fsnotify_open(struct dentry *dentry)
 {
+	inotify_open(dentry);
 }
 
 /*
@@ -86,6 +95,7 @@ static inline void fsnotify_open(struct 
  */
 static inline void fsnotify_close(struct file *file)
 {
+	inotify_close(file);
 }
 
 /*
@@ -93,6 +103,7 @@ static inline void fsnotify_close(struct
  */
 static inline void fsnotify_xattr(struct dentry *dentry)
 {
+	inotify_xattr(dentry);
 }
 
 /*
@@ -102,8 +113,29 @@ static inline void fsnotify_xattr(struct
 static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
 {
 	dnotify_change(dentry, ia_valid);
+	inotify_change(dentry, ia_valid);
 }
 
+#ifdef CONFIG_INOTIFY	/* inotify helpers */
+
+/*
+ * fsnotify_oldname_init - save off the old filename before we change it
+ */
+static inline const char *fsnotify_oldname_init(const char *name)
+{
+	return kstrdup(name, GFP_KERNEL);
+}
+
+/*
+ * snotify_oldname_free - free the name we got from fsnotify_oldname_init
+ */
+static inline void fsnotify_oldname_free(const char *old_name)
+{
+	kfree(old_name);
+}
+
+#else	/* CONFIG_INOTIFY */
+
 static inline const char *fsnotify_oldname_init(const char *name)
 {
 	return NULL;
@@ -113,6 +145,8 @@ static inline void fsnotify_oldname_free
 {
 }
 
+#endif	/* ! CONFIG_INOTIFY */
+
 #endif	/* __KERNEL__ */
 
 #endif	/* _LINUX_FS_NOTIFY_H */

Re: [RFC/PATCH 1/2] fsnotify

[David Woodhouse]

On Fri, 2005-07-08 at 18:26 -0700, Chris Wright wrote:
> Add fsnotify as infrastructure for various fs notifcation schemes.
> Move dnotify to fsnotify.

-               inode_dir_notify(dir, DN_CREATE);
+               fsnotify_create(dir, new_dentry->d_name.name);
....
+ * We don't compile any of this away in some complicated menagerie of ifdefs.
+ * Instead, we rely on the code inside to optimize away as needed.
....
+static inline void fsnotify_create(struct inode *inode, const char *name)
+{
+       dnotify_create(inode, name);
+}
....
+static inline void dnotify_create(struct inode *inode, const char *name)
+{
+       inode_dir_notify(inode, DN_CREATE);
+}

To be honest, I don't really see that this is in any way better than
what we had before. Yes, two different pieces of code actually use hooks
in similar places in the VFS code. But this 'infrastructure' just to
share those hooks is overkill as far as I can tell. It really isn't any
better than having both inotify and audit hooks side by side where we
can actually see what's going on at a glance. In fact, it's worse.

What would make sense, perhaps, would be to actually merge those hooks;
not just a cosmetic amalgamation of the calling sites. Currently, each
of inotify and the audit code does its own filtering when its hooks are
triggered, and then acts upon the event only if it affects a watched
inode. 

To actually merge that filtering code would make sense -- and then both
inotify and auditfs would just register watches on certain inodes and
receive notification as appropriate.

There are features of each which would probably be desirable in the
merged result. The inotify version grows the inode structure by quite a
lot, while the auditfs version recognises that watches will be
relatively infrequent, so uses only a bit in i_flags as a
quickly-accessible indication that an inode is 'interesting' and
maintains its actual data for that inode elsewhere. The auditfs version
is also capable of handling the "Child named 'XXXX' of this inode" kind
of watch, where watches are placed on objects which don't yet exist.
Also, the auditfs code already calls back to a separate function
auditfs_attach_wdata() in the _real_ audit code, which actually reports
when the watch is triggered; it shouldn't be hard to make it call into
an inotify function instead, depending on the type of watch which is
hit.

On the other hand, the inotify triggers require a little more
information from the original hook, which audit_notify_watch() would
need to pass through if the audit code were used as the basis for a
merged 'core watch' functionality.

-- 
dwmw2

Re: [RFC/PATCH 1/2] fsnotify

[Robert Love]

On Mon, 2005-07-11 at 13:52 +0100, David Woodhouse wrote:

> To be honest, I don't really see that this is in any way better than
> what we had before. Yes, two different pieces of code actually use hooks
> in similar places in the VFS code. But this 'infrastructure' just to
> share those hooks is overkill as far as I can tell. It really isn't any
> better than having both inotify and audit hooks side by side where we
> can actually see what's going on at a glance. In fact, it's worse.

I think what makes this patch look superfluous is that Chris added a set
of wrappers for dnotify, too.

In the inotify patch, the fsnotify wrappers call directly into the
inotify and dnotify interfaces and they do consolidate code and clean
things up.  I added fsnotify at hch's request.

Now that audit is coming along, fsnotify makes even more sense.

I would like to share some more code at a lower level, though, as you
pointed out.

I planned to look at redoing dnotify entirely on top of inotify, once
inotify is in the kernel proper, for example.

	Robert Love

Re: [RFC/PATCH 1/2] fsnotify

[Chris Wright]

* David Woodhouse (dwmw2@infradead.org) wrote:
> What would make sense, perhaps, would be to actually merge those hooks;
> not just a cosmetic amalgamation of the calling sites. Currently, each
> of inotify and the audit code does its own filtering when its hooks are
> triggered, and then acts upon the event only if it affects a watched
> inode. 

That's exactly what my intention was by posting this.  The hook site is
just enough to get the conversation going.  The really useful bits to
merge are at inode watch level.

thanks,
-chris