linux-toradex.git/fs/open.c, branch v4.19-rc5

Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2018-08-22T01:19:09+00:00

Pull overlayfs updates from Miklos Szeredi:
 "This contains two new features:

   - Stack file operations: this allows removal of several hacks from
     the VFS, proper interaction of read-only open files with copy-up,
     possibility to implement fs modifying ioctls properly, and others.

   - Metadata only copy-up: when file is on lower layer and only
     metadata is modified (except size) then only copy up the metadata
     and continue to use the data from the lower file"

* tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits)
  ovl: Enable metadata only feature
  ovl: Do not do metacopy only for ioctl modifying file attr
  ovl: Do not do metadata only copy-up for truncate operation
  ovl: add helper to force data copy-up
  ovl: Check redirect on index as well
  ovl: Set redirect on upper inode when it is linked
  ovl: Set redirect on metacopy files upon rename
  ovl: Do not set dentry type ORIGIN for broken hardlinks
  ovl: Add an inode flag OVL_CONST_INO
  ovl: Treat metacopy dentries as type OVL_PATH_MERGE
  ovl: Check redirects for metacopy files
  ovl: Move some dir related ovl_lookup_single() code in else block
  ovl: Do not expose metacopy only dentry from d_real()
  ovl: Open file with data except for the case of fsync
  ovl: Add helper ovl_inode_realdata()
  ovl: Store lower data inode in ovl_inode
  ovl: Fix ovl_getattr() to get number of blocks from lower
  ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry
  ovl: Copy up meta inode data from lowest data inode
  ovl: Modify ovl_lookup() and friends to lookup metacopy dentry
  ...

Revert "vfs: do get_write_access() on upper layer of overlayfs"

2018-07-18T13:44:43+00:00

This reverts commit 4d0c5ba2ff79ef9f5188998b29fd28fcb05f3667.

We now get write access on both overlay and underlying layers so this patch
is no longer needed for correct operation.

Signed-off-by: Miklos Szeredi

Revert "vfs: add flags to d_real()"

2018-07-18T13:44:43+00:00

This reverts commit 495e642939114478a5237a7d91661ba93b76f15a.

No user of "flags" argument of d_real() remain.

Signed-off-by: Miklos Szeredi

Revert "ovl: don't allow writing ioctl on lower layer"

2018-07-18T13:44:43+00:00

This reverts commit 7c6893e3c9abf6a9676e060a1e35e5caca673d57.

Overlayfs no longer relies on the vfs for checking writability of files.

Signed-off-by: Miklos Szeredi

vfs: don't open real

2018-07-18T13:44:42+00:00

Let overlayfs do its thing when opening a file.

This enables stacking and fixes the corner case when a file is opened for
read, modified through a writable open, and data is read from the read-only
file.  After this patch the read-only open will not return stale data even
in this case.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro

vfs: make open_with_fake_path() not contribute to nr_files

2018-07-18T13:44:40+00:00

Stacking file operations in overlay will store an extra open file for each
overlay file opened.

The overhead is just that of "struct file" which is about 256bytes, because
overlay already pins an extra dentry and inode when the file is open, which
add up to a much larger overhead.

For fear of breaking working setups, don't start accounting the extra file.

Signed-off-by: Miklos Szeredi

new helper: open_with_fake_path()

2018-07-12T15:18:42+00:00

open a file by given inode, faking ->f_path.  Use with shitloads
of caution - at the very least you'd damn better make sure that
some dentry alias of that inode is pinned down by the path in
question.  Again, this is no general-purpose interface and I hope
it will eventually go away.  Right now overlayfs wants something
like that, but nothing else should.

Any out-of-tree code with bright idea of using this one *will*
eventually get hurt, with zero notice and great delight on my part.
I refuse to use EXPORT_SYMBOL_GPL(), especially in situations when
it's really EXPORT_SYMBOL_DONT_USE_IT(), but don't take that export
as "you are welcome to use it".

Signed-off-by: Al Viro

->atomic_open(): return 0 in all success cases

2018-07-12T14:04:21+00:00

FMODE_OPENED can be used to distingusish "successful open" from the
"called finish_no_open(), do it yourself" cases.  Since finish_no_open()
has been adjusted, no changes in the instances were actually needed.
The caller has been adjusted.

Acked-by: Linus Torvalds 
Signed-off-by: Al Viro

getting rid of 'opened' argument of ->atomic_open() - part 1

2018-07-12T14:04:19+00:00

'opened' argument of finish_open() is unused.  Kill it.

Signed-off-by Al Viro

switch all remaining checks for FILE_OPENED to FMODE_OPENED

2018-07-12T14:04:18+00:00

... and don't bother with setting FILE_OPENED at all.

Acked-by: Linus Torvalds 
Signed-off-by: Al Viro