kernel.git/fs/overlayfs/export.c, branch linux-6.7.y

ovl: reorder ovl_want_write() after ovl_inode_lock()

2023-10-30T22:12:57Z

Make the locking order of ovl_inode_lock() strictly between the two vfs stacked layers, i.e.: - ovl vfs locks: sb_writers, inode_lock, ... - ovl_inode_lock - upper vfs locks: sb_writers, inode_lock, ... To that effect, move ovl_want_write() into the helpers ovl_nlink_start() and ovl_copy_up_start which currently take the ovl_inode_lock() after ovl_want_write(). Signed-off-by: Amir Goldstein

ovl: fix NULL pointer defer when encoding non-decodable lower fid

2023-10-03T06:24:11Z

A wrong return value from ovl_check_encode_origin() would cause ovl_dentry_to_fid() to try to encode fid from NULL upper dentry. Reported-by: syzbot+2208f82282740c1c8915@syzkaller.appspotmail.com Fixes: 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles") Signed-off-by: Amir Goldstein

ovl: make consistent use of OVL_FS()

2023-08-12T16:02:54Z

Always use OVL_FS() to retrieve the corresponding struct ovl_fs from a struct super_block. Reviewed-by: Amir Goldstein Signed-off-by: Andrea Righi Signed-off-by: Amir Goldstein

ovl: support encoding non-decodable file handles

2023-08-12T16:02:47Z

When all layers support file handles, we support encoding non-decodable file handles (a.k.a. fid) even with nfs_export=off. When file handles do not need to be decoded, we do not need to copy up redirected lower directories on encode, and we encode also non-indexed upper with lower file handle, so fid will not change on copy up. This enables reporting fanotify events with file handles on overlayfs with default config/mount options. Signed-off-by: Amir Goldstein

ovl: deduplicate lowerpath and lowerstack[]

2023-06-19T11:01:13Z

The ovl_inode contains a copy of lowerpath in lowerstack[0], so the lowerpath member can be removed. Use accessor ovl_lowerpath() to get the lowerpath whereever the member was accessed directly. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: move ovl_entry into ovl_inode

2023-06-19T11:01:13Z

The lower stacks of all the ovl inode aliases should be identical and there is redundant information in ovl_entry and ovl_inode. Move lowerstack into ovl_inode and keep only the OVL_E_FLAGS per overlay dentry. Following patches will deduplicate redundant ovl_inode fields. Note that for pure upper and negative dentries, OVL_E(dentry) may be NULL now, so it is imporatnt to use the ovl_numlower() accessor. Reviewed-by: Alexander Larsson Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: use ovl_numlower() and ovl_lowerstack() accessors

2023-06-19T11:01:13Z

This helps fortify against dereferencing a NULL ovl_entry, before we move the ovl_entry reference into ovl_inode. Reviewed-by: Alexander Larsson Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: use OVL_E() and OVL_E_FLAGS() accessors

2023-06-19T11:01:12Z

Instead of open coded instances, because we are about to split the two apart. Reviewed-by: Alexander Larsson Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

ovl: update of dentry revalidate flags after copy up

2023-06-19T11:01:12Z

After copy up, we may need to update d_flags if upper dentry is on a remote fs and lower dentries are not. Add helpers to allow incremental update of the revalidate flags. Fixes: bccece1ead36 ("ovl: allow remote upper") Reviewed-by: Gao Xiang Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi

fs: port ->permission() to pass mnt_idmap

2023-01-19T08:24:28Z

Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft)