From: Josef Bacik Date: Fri, 19 Nov 2010 20:36:10 +0000 (+0000) Subject: Btrfs: hold i_mutex when calling btrfs_log_dentry_safe X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=495e86779f4f319828bc10dfc0c9ac2161868077;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git Btrfs: hold i_mutex when calling btrfs_log_dentry_safe Since we walk up the path logging all of the parts of the inode's path, we need to hold i_mutex to make sure that the inode is not renamed while we're logging everything. btrfs_log_dentry_safe does dget_parent and all of that jazz, but we may get unexpected results if the rename changes the inode's location while we're higher up the path logging those dentries, so do this for safety reasons. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index e354c33df082..c1faded5fca0 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1047,8 +1047,14 @@ out: if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) { trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + num_written = PTR_ERR(trans); + goto done; + } + mutex_lock(&inode->i_mutex); ret = btrfs_log_dentry_safe(trans, root, file->f_dentry); + mutex_unlock(&inode->i_mutex); if (ret == 0) { ret = btrfs_sync_log(trans, root); if (ret == 0) @@ -1067,6 +1073,7 @@ out: (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT); } } +done: current->backing_dev_info = NULL; return num_written ? num_written : err; }