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[PATCH] inotify

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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>
This commit is contained in:
Robert Love
2005-07-12 17:06:03 -04:00
committed by Linus Torvalds
parent bd4c625c06
commit 0eeca28300
24 changed files with 1639 additions and 67 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
fs/attr.c
View File

@@ -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, struct iattr * attr)
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, struct iattr * attr)
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;
}