[PATCH] inotify

inotify is intended to correct the deficiencies of dnotify, particularly
its inability to scale and its terrible user interface:

        * dnotify requires the opening of one fd per each directory
          that you intend to watch. This quickly results in too many
          open files and pins removable media, preventing unmount.
        * dnotify is directory-based. You only learn about changes to
          directories. Sure, a change to a file in a directory affects
          the directory, but you are then forced to keep a cache of
          stat structures.
        * dnotify's interface to user-space is awful.  Signals?

inotify provides a more usable, simple, powerful solution to file change
notification:

        * inotify's interface is a system call that returns a fd, not SIGIO.
	  You get a single fd, which is select()-able.
        * inotify has an event that says "the filesystem that the item
          you were watching is on was unmounted."
        * inotify can watch directories or files.

Inotify is currently used by Beagle (a desktop search infrastructure),
Gamin (a FAM replacement), and other projects.

See Documentation/filesystems/inotify.txt.

Signed-off-by: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 16 insertions, 14 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 1d93cb4f7c5f..02a824cd3c5c 100644
--- a/fs/namei.c
+++ b/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 dentry *dentry, int mode,
         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 dentry *dentry, int mode, dev_t dev)
         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 dentry *dentry, int mode)
         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 dentry *dentry)
         }
         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 dentry *dentry)
 
         /* 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, struct dentry *dentry, const char *oldname, i
         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, struct inode *dir, struct dentry *new_de
         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, struct dentry *old_dentry,
 {
         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, struct dentry *old_dentry,
         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;
 }