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authorVasily Averin <vvs@sw.ru>2006-10-28 10:38:44 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-28 11:30:53 -0700
commit6eac3f93f5e6b7256fb20b7608d62ec192da12be (patch)
treea829571b473072fb764e179499a8610789ba284e
parentebed4bfc8da8df5b6b0bc4a5064a949f04683509 (diff)
[PATCH] missing unused dentry in prune_dcache()?
On the the following patch: http://linux.bkbits.net:8080/linux-2.6/gnupatch@449b144ecSF1rYskg3q-SeR2vf88zg # ChangeSet # 2006/06/22 15:05:57-07:00 neilb@suse.de # [PATCH] Fix dcache race during umount # If prune_dcache finds a dentry that it cannot free, it leaves it where it # is (at the tail of the list) and exits, on the assumption that some other # thread will be removing that dentry soon. However as far as I see this comment is not correct: when we cannot take s_umount rw_semaphore (for example because it was taken in do_remount) this dentry is already extracted from dentry_unused list and we do not add it into the list again. Therefore dentry will not be found by prune_dcache() and shrink_dcache_sb() and will leave in memory very long time until the partition will be unmounted. The patch adds this dentry into tail of the dentry_unused list. Signed-off-by: Vasily Averin <vvs@sw.ru> Cc: Neil Brown <neilb@suse.de> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/dcache.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index a1ff91eef10..a5b76b647c6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -478,11 +478,12 @@ static void prune_dcache(int count, struct super_block *sb)
up_read(s_umount);
}
spin_unlock(&dentry->d_lock);
- /* Cannot remove the first dentry, and it isn't appropriate
- * to move it to the head of the list, so give up, and try
- * later
+ /*
+ * Insert dentry at the head of the list as inserting at the
+ * tail leads to a cycle.
*/
- break;
+ list_add(&dentry->d_lru, &dentry_unused);
+ dentry_stat.nr_unused++;
}
spin_unlock(&dcache_lock);
}