From 7ea6040b0eff07d3a9a4e2d248ac137c6ad02d42 Mon Sep 17 00:00:00 2001 From: John McCutchan Date: Tue, 6 Sep 2005 15:18:02 -0700 Subject: [PATCH] [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 Signed-off-by: Robert Love Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/inotify.c | 9 ++++++++- include/linux/inotify.h | 1 + 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/inotify.c b/fs/inotify.c index 2fd97ef547ff..a37e9fb1da58 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -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; } diff --git a/include/linux/inotify.h b/include/linux/inotify.h index 93bb3afe646b..ee5b239092ed 100644 --- a/include/linux/inotify.h +++ b/include/linux/inotify.h @@ -47,6 +47,7 @@ struct inotify_event { #define IN_MOVE (IN_MOVED_FROM | IN_MOVED_TO) /* moves */ /* special flags */ +#define IN_MASK_ADD 0x20000000 /* add to the mask of an already existing watch */ #define IN_ISDIR 0x40000000 /* event occurred against dir */ #define IN_ONESHOT 0x80000000 /* only send event once */ -- GitLab