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authorChristoph Hellwig <hch@lst.de>2010-06-09 15:31:01 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-06-11 12:58:08 +0200
commit29cb48594b873f6193d6327097e504bd3e2314de (patch)
tree1c93364fd70d93d42c6749c261f96f84a66d71e2 /fs
parent334132ae921a14ac2b2ba48e174136f7f2c9aae1 (diff)
writeback: fix pin_sb_for_writeback
We need to check for s_instances to make sure we don't bother working against a filesystem that is beeing unmounted, and we need to call put_super to make sure a superblock is freed when we race against umount. Also no need to keep sb_lock after we got a reference on it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/fs-writeback.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 3a066e91ec8..0609607d395 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -534,19 +534,21 @@ select_queue:
static bool pin_sb_for_writeback(struct super_block *sb)
{
spin_lock(&sb_lock);
+ if (list_empty(&sb->s_instances)) {
+ spin_unlock(&sb_lock);
+ return false;
+ }
+
sb->s_count++;
+ spin_unlock(&sb_lock);
+
if (down_read_trylock(&sb->s_umount)) {
- if (sb->s_root) {
- spin_unlock(&sb_lock);
+ if (sb->s_root)
return true;
- }
- /*
- * umounted, drop rwsem again and fall through to failure
- */
up_read(&sb->s_umount);
}
- sb->s_count--;
- spin_unlock(&sb_lock);
+
+ put_super(sb);
return false;
}