| Message ID | 95327ddd01e86d0160c2d678f4306a737cb6a085.1524823321.git.h.grohne@intenta.de |
|---|---|
| State | New, archived |
| Delegated to: | David Woodhouse |
| Headers | show |
| Series | jffs2: fix lockdep warning | expand |
On Fri, Apr 27, 2018 at 12:37 PM Helmut Grohne <h.grohne@intenta.de> wrote: > > At the point where f->sem is taken, we know that we have a locked I_NEW > inode. Since jffs2_iget is the only function processing I_NEW inodes and > iget_locked blocks on I_NEW inodes, we know that we are the only user of > the inode until we unlock_new_inode it. Since 7aaea7605c0 ("jffs2: fix > unbalanced locking"), jffs2_do_read_inode no longer touches f->sem and > does not make the inode visible to others either. Thus we can call it > without f->sem acquired. Nextup, inode->i_mode is protected until > unlock_new_inode. > > After deferring the locking, we can decide upon the proper lock class > depending on inode->i_mode. > > Signed-off-by: Helmut Grohne <h.grohne@intenta.de> > Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Richard Weinberger <richard@nod.at>
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c index eab04eca95a3..89a10b398d00 100644 --- a/fs/jffs2/fs.c +++ b/fs/jffs2/fs.c @@ -270,13 +270,15 @@ struct inode *jffs2_iget(struct super_block *sb, unsigned long ino) c = JFFS2_SB_INFO(inode->i_sb); jffs2_init_inode_info(f); - mutex_lock(&f->sem); ret = jffs2_do_read_inode(c, f, inode->i_ino, &latest_node); if (ret) goto error; inode->i_mode = jemode_to_cpu(latest_node.mode); + + mutex_lock(&f->sem); + i_uid_write(inode, je16_to_cpu(latest_node.uid)); i_gid_write(inode, je16_to_cpu(latest_node.gid)); inode->i_size = je32_to_cpu(latest_node.isize);
At the point where f->sem is taken, we know that we have a locked I_NEW inode. Since jffs2_iget is the only function processing I_NEW inodes and iget_locked blocks on I_NEW inodes, we know that we are the only user of the inode until we unlock_new_inode it. Since 7aaea7605c0 ("jffs2: fix unbalanced locking"), jffs2_do_read_inode no longer touches f->sem and does not make the inode visible to others either. Thus we can call it without f->sem acquired. Nextup, inode->i_mode is protected until unlock_new_inode. After deferring the locking, we can decide upon the proper lock class depending on inode->i_mode. Signed-off-by: Helmut Grohne <h.grohne@intenta.de> Cc: Peter Zijlstra <peterz@infradead.org> --- fs/jffs2/fs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)