From 2ba9d57e65044859f7ff133bcb0a902769bf3bc6 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 3 Jan 2018 18:54:41 +0200 Subject: [PATCH] ovl: take mnt_want_write() for work/index dir setup There are several write operations on upper fs not covered by mnt_want_write(): - test set/remove OPAQUE xattr - test create O_TMPFILE - set ORIGIN xattr in ovl_verify_origin() - cleanup of index entries in ovl_indexdir_cleanup() Some of these go way back, but this patch only applies over the v4.14 re-factoring of ovl_fill_super(). Cc: #v4.14 Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/super.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 1a436fa92a04..3387e6d639a5 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -521,10 +521,6 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, bool retried = false; bool locked = false; - err = mnt_want_write(mnt); - if (err) - goto out_err; - inode_lock_nested(dir, I_MUTEX_PARENT); locked = true; @@ -589,7 +585,6 @@ retry: goto out_err; } out_unlock: - mnt_drop_write(mnt); if (locked) inode_unlock(dir); @@ -930,12 +925,17 @@ out: static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) { + struct vfsmount *mnt = ofs->upper_mnt; struct dentry *temp; int err; + err = mnt_want_write(mnt); + if (err) + return err; + ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); if (!ofs->workdir) - return 0; + goto out; /* * Upper should support d_type, else whiteouts are visible. Given @@ -945,7 +945,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) */ err = ovl_check_d_type_supported(workpath); if (err < 0) - return err; + goto out; /* * We allowed this configuration and don't want to break users over @@ -969,6 +969,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) if (err) { ofs->noxattr = true; pr_warn("overlayfs: upper fs does not support xattr.\n"); + err = 0; } else { vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE); } @@ -980,7 +981,9 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); } - return 0; +out: + mnt_drop_write(mnt); + return err; } static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath) @@ -1027,8 +1030,13 @@ out: static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe, struct path *upperpath) { + struct vfsmount *mnt = ofs->upper_mnt; int err; + err = mnt_want_write(mnt); + if (err) + return err; + /* Verify lower root is upper root origin */ err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry, false, true); @@ -1056,6 +1064,7 @@ static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe, pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); out: + mnt_drop_write(mnt); return err; } -- 2.39.5