From 0eeca28300df110bd6ed54b31193c83b87921443 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Tue, 12 Jul 2005 17:06:03 -0400 Subject: [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 Cc: John McCutchan Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fs.h | 6 +- include/linux/fsnotify.h | 248 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/inotify.h | 108 +++++++++++++++++++++ include/linux/sched.h | 4 + include/linux/sysctl.h | 11 ++- 5 files changed, 375 insertions(+), 2 deletions(-) create mode 100644 include/linux/fsnotify.h create mode 100644 include/linux/inotify.h (limited to 'include/linux') diff --git a/include/linux/fs.h b/include/linux/fs.h index 302ec20838c..c9bf3746a9f 100644 --- a/include/linux/fs.h +++ b/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 */ @@ -1393,7 +1398,6 @@ 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, diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h new file mode 100644 index 00000000000..eb581b6cfca --- /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 +#include + +/* + * 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 00000000000..a40c2bf0408 --- /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 + +/* + * 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 +#include +#include + +#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 ff48815bd3a..dec5827c774 100644 --- a/include/linux/sched.h +++ b/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 ? */ diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 5b5f434ac9a..ce19a2aa0b2 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -61,7 +61,8 @@ enum 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 @@ enum 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 { -- cgit v1.2.3