This is a note to let you know that I've just added the patch titled

ovl: take mnt_want_write() for work/index dir setup

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ovl-take-mnt_want_write-for-work-index-dir-setup.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 2ba9d57e65044859f7ff133bcb0a902769bf3bc6 Mon Sep 17 00:00:00 2001

From: Amir Goldstein amir73il@gmail.com Date: Wed, 3 Jan 2018 18:54:41 +0200 Subject: ovl: take mnt_want_write() for work/index dir setup

From: Amir Goldstein amir73il@gmail.com

commit 2ba9d57e65044859f7ff133bcb0a902769bf3bc6 upstream.

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().

Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/overlayfs/super.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)

--- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -520,10 +520,6 @@ static struct dentry *ovl_workdir_create 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;

@@ -588,7 +584,6 @@ 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_f */ 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_f 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_f 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_f 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; }

Patches currently in stable-queue which might be from amir73il@gmail.com are

queue-4.15/ovl-take-mnt_want_write-for-removing-impure-xattr.patch queue-4.15/ovl-take-mnt_want_write-for-work-index-dir-setup.patch queue-4.15/ovl-hash-directory-inodes-for-fsnotify.patch queue-4.15/ovl-force-r-o-mount-when-index-dir-creation-fails.patch queue-4.15/ovl-fix-failure-to-fsync-lower-dir.patch