[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>
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index e25e4c7..a7cb377 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -296,8 +296,11 @@
#define __NR_keyctl 288
#define __NR_ioprio_set 289
#define __NR_ioprio_get 290
+#define __NR_inotify_init 291
+#define __NR_inotify_add_watch 292
+#define __NR_inotify_rm_watch 293
-#define NR_syscalls 291
+#define NR_syscalls 294
/*
* user-visible error numbers are in the range -1 - -128: see
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 302ec20..c9bf374 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -474,6 +474,11 @@
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 */
@@ -1393,7 +1398,6 @@
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,
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
new file mode 100644
index 0000000..eb581b6
--- /dev/null
+++ b/include/linux/fsnotify.h
@@ -0,0 +1,248 @@
+#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>
+#include <linux/inotify.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)
+{
+ u32 cookie = inotify_get_cookie();
+
+ 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);
+ }
+
+ 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);
+}
+
+/*
+ * fsnotify_unlink - file was unlinked
+ */
+static inline void fsnotify_unlink(struct dentry *dentry, struct inode *dir)
+{
+ struct inode *inode = dentry->d_inode;
+
+ inode_dir_notify(dir, DN_DELETE);
+ 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);
+}
+
+/*
+ * fsnotify_rmdir - directory was removed
+ */
+static inline void fsnotify_rmdir(struct dentry *dentry, struct inode *inode,
+ struct inode *dir)
+{
+ inode_dir_notify(dir, DN_DELETE);
+ 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);
+}
+
+/*
+ * fsnotify_create - 'name' was linked in
+ */
+static inline void fsnotify_create(struct inode *inode, const char *name)
+{
+ inode_dir_notify(inode, DN_CREATE);
+ inotify_inode_queue_event(inode, IN_CREATE, 0, name);
+}
+
+/*
+ * fsnotify_mkdir - directory 'name' was created
+ */
+static inline void fsnotify_mkdir(struct inode *inode, const char *name)
+{
+ inode_dir_notify(inode, DN_CREATE);
+ inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, name);
+}
+
+/*
+ * fsnotify_access - file was read
+ */
+static inline void fsnotify_access(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_ACCESS;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ dnotify_parent(dentry, DN_ACCESS);
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_modify - file was modified
+ */
+static inline void fsnotify_modify(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ u32 mask = IN_MODIFY;
+
+ if (S_ISDIR(inode->i_mode))
+ mask |= IN_ISDIR;
+
+ dnotify_parent(dentry, DN_MODIFY);
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+ inotify_inode_queue_event(inode, mask, 0, NULL);
+}
+
+/*
+ * fsnotify_open - file was opened
+ */
+static inline void fsnotify_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);
+}
+
+/*
+ * fsnotify_close - file was closed
+ */
+static inline void fsnotify_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);
+}
+
+/*
+ * fsnotify_xattr - extended attributes were changed
+ */
+static inline void fsnotify_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);
+}
+
+/*
+ * 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)
+{
+ struct inode *inode = dentry->d_inode;
+ int dn_mask = 0;
+ u32 in_mask = 0;
+
+ if (ia_valid & ATTR_UID) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+ if (ia_valid & ATTR_GID) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+ if (ia_valid & ATTR_SIZE) {
+ in_mask |= IN_MODIFY;
+ dn_mask |= DN_MODIFY;
+ }
+ /* both times implies a utime(s) call */
+ if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
+ {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ } else if (ia_valid & ATTR_ATIME) {
+ in_mask |= IN_ACCESS;
+ dn_mask |= DN_ACCESS;
+ } else if (ia_valid & ATTR_MTIME) {
+ in_mask |= IN_MODIFY;
+ dn_mask |= DN_MODIFY;
+ }
+ if (ia_valid & ATTR_MODE) {
+ in_mask |= IN_ATTRIB;
+ dn_mask |= DN_ATTRIB;
+ }
+
+ if (dn_mask)
+ dnotify_parent(dentry, dn_mask);
+ 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);
+ }
+}
+
+#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);
+}
+
+/*
+ * fsnotify_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;
+}
+
+static inline void fsnotify_oldname_free(const char *old_name)
+{
+}
+
+#endif /* ! CONFIG_INOTIFY */
+
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_FS_NOTIFY_H */
diff --git a/include/linux/inotify.h b/include/linux/inotify.h
new file mode 100644
index 0000000..a40c2bf
--- /dev/null
+++ b/include/linux/inotify.h
@@ -0,0 +1,108 @@
+/*
+ * 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 */
+};
+
+/* 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)
+
+#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);
+
+#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;
+}
+
+#endif /* CONFIG_INOTIFY */
+
+#endif /* __KERNEL __ */
+
+#endif /* _LINUX_INOTIFY_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ff48815..dec5827 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -410,6 +410,10 @@
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 ? */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 5b5f434..ce19a2a 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -61,7 +61,8 @@
CTL_DEV=7, /* Devices */
CTL_BUS=8, /* Busses */
CTL_ABI=9, /* Binary emulation */
- CTL_CPU=10 /* CPU stuff (speed scaling, etc) */
+ CTL_CPU=10, /* CPU stuff (speed scaling, etc) */
+ CTL_INOTIFY=11 /* Inotify */
};
/* CTL_BUS names: */
@@ -70,6 +71,14 @@
CTL_BUS_ISA=1 /* ISA */
};
+/* CTL_INOTIFY names: */
+enum
+{
+ INOTIFY_MAX_USER_DEVICES=1, /* max number of inotify device instances per user */
+ INOTIFY_MAX_USER_WATCHES=2, /* max number of inotify watches per user */
+ INOTIFY_MAX_QUEUED_EVENTS=3 /* Max number of queued events per inotify device instance */
+};
+
/* CTL_KERN names: */
enum
{