The patch titled
inotify fix for unexected IDR behaviour
has been added to the -mm tree. Its filename is
inotify-fix-for-unexpected-idr-behaviour.patch
Patches currently in -mm which might be from [EMAIL PROTECTED] are
inotify-fix-for-unexpected-idr-behaviour.patch
inotify-speedup.patch
fsnotify-hook-on-removexattr-too.patch
From: John McCutchan <[EMAIL PROTECTED]>
Jim Houston <[EMAIL PROTECTED]> wrote:
>
> It looks like we have an "off by one" problem with idr_get_new_above()
> which may be part of the inotify problem. I'm not sure if the problem
> is the behavior or the name & comments. The start_id parameter is the
> starting point for the idr allocation search, and if it is available, it
> will be allocated. If you pass in the last id allocated as the start_id
> and it has already been freed (by an idr_remove call), it will be
> allocated again. The obvious fix would be to increment start_id
> in idr_get_new_above().
This fixed the inotify problem. But where to put the fix is turning into a
bit of a mess. Some callers like drivers/md/dm.c:682 call
idr_get_new_above as if it will return >= starting_id. The comment says
that it will return > starting_id, and the function name leads people to
believe the same thing.
In the patch below I change inotify do add one to the value was pass into
idr. I also change the comment to more accurately reflect what the
function does. The function name doesn't fit, but it never did.
Signed-off-by: John McCutchan <[EMAIL PROTECTED]>
Cc: Robert Love <[EMAIL PROTECTED]>
Cc: george anzinger <[email protected]>
Cc: Neil Brown <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
fs/inotify.c | 2 +-
lib/idr.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff -puN fs/inotify.c~inotify-fix-for-unexpected-idr-behaviour fs/inotify.c
--- devel/fs/inotify.c~inotify-fix-for-unexpected-idr-behaviour 2005-08-26
11:55:02.000000000 -0700
+++ devel-akpm/fs/inotify.c 2005-08-26 11:55:02.000000000 -0700
@@ -353,7 +353,7 @@ static int inotify_dev_get_wd(struct ino
do {
if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL)))
return -ENOSPC;
- ret = idr_get_new_above(&dev->idr, watch, dev->last_wd,
&watch->wd);
+ ret = idr_get_new_above(&dev->idr, watch, dev->last_wd+1,
&watch->wd);
} while (ret == -EAGAIN);
return ret;
diff -puN lib/idr.c~inotify-fix-for-unexpected-idr-behaviour lib/idr.c
--- devel/lib/idr.c~inotify-fix-for-unexpected-idr-behaviour 2005-08-26
11:55:02.000000000 -0700
+++ devel-akpm/lib/idr.c 2005-08-26 11:55:02.000000000 -0700
@@ -207,7 +207,7 @@ build_up:
}
/**
- * idr_get_new_above - allocate new idr entry above a start id
+ * idr_get_new_above - allocate new idr entry above or equal to a start id
* @idp: idr handle
* @ptr: pointer you want associated with the ide
* @start_id: id to start search at
_
-
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