linux-kernel - [PATCH 2/2] jffs2: handle INO_STATE_CLEARING in jffs2_do_read

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Date:   Wed, 20 Feb 2019 18:21:33 +0800
From:   Hou Tao <houtao1@...wei.com>
To:     <linux-mtd@...ts.infradead.org>
CC:     David Woodhouse <dwmw2@...radead.org>,
        Richard Weinberger <richard@....at>,
        <linux-kernel@...r.kernel.org>, <houtao1@...wei.com>
Subject: [PATCH 2/2] jffs2: handle INO_STATE_CLEARING in jffs2_do_read_inode()

For inode that fails to be created midway, GC procedure may
try to GC its dnode, and in the following case BUG() will be
triggered:

CPU 0                       CPU 1
in jffs2_do_create()        in jffs2_garbage_collect_pass()

jffs2_write_dnode succeed
// for dirent
jffs2_reserve_space fail

			    inum = ic->ino
			    nlink = ic->pino_nlink (> 0)

iget_failed
  make_bad_inode
    remove_inode_hash
  iput
    jffs2_evict_inode
      jffs2_do_clear_inode
        jffs2_set_inocache_state(INO_STATE_CLEARING)

			    jffs2_gc_fetch_inode
			      jffs2_iget
			        // a new inode is created because
			        // the old inode had been unhashed
			        iget_locked
			      jffs2_do_read_inode
			        jffs2_get_ino_cache
				// assert BUG()
				f->inocache->state = INO_STATE_CLEARING

Fix it by waiting for its state changes to INO_STATE_CHECKEDABSENT.

Fixes: 67e345d17ff8 ("[JFFS2] Prevent ino cache removal for inodes in use")
Cc: stable@...r.kernel.org
Signed-off-by: Hou Tao <houtao1@...wei.com>
---
 fs/jffs2/readinode.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index 389ea53ea487..0bae0583106e 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -1328,6 +1328,7 @@ int jffs2_do_read_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
 
 		case INO_STATE_CHECKING:
 		case INO_STATE_GC:
+		case INO_STATE_CLEARING:
 			/* If it's in either of these states, we need
 			   to wait for whoever's got it to finish and
 			   put it back. */
-- 
2.16.2.dirty