From: Maneesh Soni <firstname.lastname@example.org> To: James W McMechan <email@example.com> Cc: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org Subject: Re: Oops with tmpfs on both 2.4.22 & 2.6.0-test11 Date: Wed, 3 Dec 2003 17:32:44 +0530 [thread overview] Message-ID: <20031203120244.GA1311@in.ibm.com> (raw) In-Reply-To: <email@example.com> On Wed, Dec 03, 2003 at 03:06:14AM -0800, James W McMechan wrote: [..] > > > > The cursor adjustment in dcache_dir_lseek() (fs/libfs.c: line 90) > > always puts the cursor just before the last looked dentry in the > > while loop. > > > > But it is problematic when we have an empty directory and > > (file->f_pos == 2) > > In this case we have the loop counter p pointing to the cursor and > > doing list_del and list_add_tail of the same list node results in oops. > > > This is where I get mildly lost, from what you are saying here I > would have expected a test on list_empty rather than on > fpos==2 also this occurs in every file, will starting in a different > pos in the list cause problems? The cursor dentry is added in d_subdirs list in the ->open call for the directory. So even if directory is empty from a user point of view, the d_subdirs list will ateast have the cursor dentry. In other words when we come to ->lseek or ->readdir call, we will not have empty d_subdirs list. > > With further testing it also Oops even when the dir is not empty > I did a "touch /dev/shm/1 /dev/shm/2 /dev/shm/3" to put some > entries in the dir first and the original still oops at offset 2 > > I should do more testing, to see if I can find out what happens > on non empty dirs, because I was thinking it was due to the > dir being empty, which now appears not to be true. humm.. yeah.. the original case will always oops for offset 2 irrespective of whether directory is empty or not. Because in case of non-empty dir also we will have p pointing to cursor dentry for offset 2. Thanks for letting me know one more fact. > > > The following patch takes (file->f_post == 2) as a special case and > > adjusts the cursor dentry by putting it right at the beginning of the > > d_subdirs list. > > > Also is the new variable dentry needed or just a optimization? > It looks functionally equivalent, but perhaps it is needed for > something I am not seeing at the moment. That's just to make code readable, without this it will have line beyond 80 columns and also it has to de-reference multiple levels of pointers. Thanks Maneesh -- Maneesh Soni Linux Technology Center, IBM Software Lab, Bangalore, India email: firstname.lastname@example.org Phone: 91-80-5044999 Fax: 91-80-5268553 T/L : 9243696
next prev parent reply other threads:[~2003-12-03 12:04 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-12-03 11:06 James W McMechan 2003-12-03 12:02 ` Maneesh Soni [this message] [not found] <email@example.com> 2003-12-08 5:10 ` Maneesh Soni -- strict thread matches above, loose matches on Subject: below -- 2003-12-07 22:48 James McMechan 2003-12-01 2:59 James W McMechan 2003-12-01 11:37 ` Maneesh Soni 2003-12-01 2:06 James W McMechan 2003-12-01 4:51 ` William Lee Irwin III 2003-12-01 1:06 James W McMechan 2003-12-01 3:43 ` William Lee Irwin III 2003-11-30 21:17 James W McMechan 2003-12-01 1:21 ` William Lee Irwin III 2003-12-01 7:58 ` Andries Brouwer 2003-12-01 8:00 ` William Lee Irwin III 2003-11-30 17:34 James W McMechan 2003-11-30 20:06 ` William Lee Irwin III 2003-11-30 21:21 ` Oleg Drokin 2003-11-30 16:57 James W McMechan 2003-11-30 19:27 ` William Lee Irwin III
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