[PATCH] inotify: fix event loss on hardlinked files

People have run into a problem when they do this:

watch (file1, all_events);
watch (file2, some_events);

if file2 is a hard link to file1, some events will be missed because by
default we replace the mask.  The patch below adds a flag IN_MASK_ADD which
will cause inotify to add to the existing mask if present.

Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
John McCutchan
2005-09-06 15:18:02 -07:00
committed by Linus Torvalds
parent 8191151d09
commit 7ea6040b0e
2 changed files with 9 additions and 1 deletions

View File

@ -931,6 +931,7 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
struct nameidata nd;
struct file *filp;
int ret, fput_needed;
int mask_add = 0;
filp = fget_light(fd, &fput_needed);
if (unlikely(!filp))
@ -953,6 +954,9 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
down(&inode->inotify_sem);
down(&dev->sem);
if (mask & IN_MASK_ADD)
mask_add = 1;
/* don't let user-space set invalid bits: we don't want flags set */
mask &= IN_ALL_EVENTS;
if (unlikely(!mask)) {
@ -966,7 +970,10 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
*/
old = inode_find_dev(inode, dev);
if (unlikely(old)) {
old->mask = mask;
if (mask_add)
old->mask |= mask;
else
old->mask = mask;
ret = old->wd;
goto out;
}