linux.git/fs/ext2/file.c, branch v6.3

fs: rename current get acl method

2022-10-20T08:13:27+00:00

The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

The current inode operation for getting posix acls takes an inode
argument but various filesystems (e.g., 9p, cifs, overlayfs) need access
to the dentry. In contrast to the ->set_acl() inode operation we cannot
simply extend ->get_acl() to take a dentry argument. The ->get_acl()
inode operation is called from:

acl_permission_check()
-> check_acl()
   -> get_acl()

which is part of generic_permission() which in turn is part of
inode_permission(). Both generic_permission() and inode_permission() are
called in the ->permission() handler of various filesystems (e.g.,
overlayfs). So simply passing a dentry argument to ->get_acl() would
amount to also having to pass a dentry argument to ->permission(). We
should avoid this unnecessary change.

So instead of extending the existing inode operation rename it from
->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that
passes a dentry argument and which filesystems that need access to the
dentry can implement instead of ->get_inode_acl(). Filesystems like cifs
which allow setting and getting posix acls but not using them for
permission checking during lookup can simply not implement
->get_inode_acl().

This is intended to be a non-functional change.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Suggested-by/Inspired-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner (Microsoft)

ext2: Convert to using invalidate_lock

2021-07-13T12:29:00+00:00

Ext2 has its private dax_sem used for synchronizing page faults and
truncation. Use mapping->invalidate_lock instead as it is meant for this
purpose.

CC: 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara

ext2: convert to fileattr

2021-04-12T13:04:29+00:00

Use the fileattr API to let the VFS handle locking, permission checking and
conversion.

Signed-off-by: Miklos Szeredi 
Cc: Jan Kara

ext2: don't update mtime on COW faults

2020-09-05T17:00:05+00:00

When running in a dax mode, if the user maps a page with MAP_PRIVATE and
PROT_WRITE, the ext2 filesystem would incorrectly update ctime and mtime
when the user hits a COW fault.

This breaks building of the Linux kernel.  How to reproduce:

 1. extract the Linux kernel tree on dax-mounted ext2 filesystem
 2. run make clean
 3. run make -j12
 4. run make -j12

at step 4, make would incorrectly rebuild the whole kernel (although it
was already built in step 3).

The reason for the breakage is that almost all object files depend on
objtool.  When we run objtool, it takes COW page fault on its .data
section, and these faults will incorrectly update the timestamp of the
objtool binary.  The updated timestamp causes make to rebuild the whole
tree.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

ext2: code cleanup by removing ifdef macro surrounding

2020-05-22T13:11:00+00:00

Define ext2_listxattr to NULL when CONFIG_EROFS_FS_XATTR
is not enabled, then we can remove many ugly ifdef macros
in the code.

Link: https://lore.kernel.org/r/20200522044035.24190-2-cgxu519@mykernel.net
Signed-off-by: Chengguang Xu 
Signed-off-by: Jan Kara

ext2: support statx syscall

2019-02-18T14:14:43+00:00

Since statx, every filesystem should fill the attributes/attributes_mask
in routine getattr. But the generic_fillattr has not fill that, so add
ext2_getattr to do this. This can fix generic/424 while testing ext2.

Reviewed-by: zhangyi (F) 
Signed-off-by: yangerkun 
Signed-off-by: Jan Kara

dax: remove VM_MIXEDMAP for fsdax and device dax

2018-08-17T23:20:27+00:00

This patch is reworked from an earlier patch that Dan has posted:
https://patchwork.kernel.org/patch/10131727/

VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that
the memory page it is dealing with is not typical memory from the linear
map.  The get_user_pages_fast() path, since it does not resolve the vma,
is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we
use that as a VM_MIXEDMAP replacement in some locations.  In the cases
where there is no pte to consult we fallback to using vma_is_dax() to
detect the VM_MIXEDMAP special case.

Now that we have explicit driver pfn_t-flag opt-in/opt-out for
get_user_pages() support for DAX we can stop setting VM_MIXEDMAP.  This
also means we no longer need to worry about safely manipulating vm_flags
in a future where we support dynamically changing the dax mode of a
file.

DAX should also now be supported with madvise_behavior(), vma_merge(),
and copy_page_range().

This patch has been tested against ndctl unit test.  It has also been
tested against xfstests commit: 625515d using fake pmem created by
memmap and no additional issues have been observed.

Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang 
Acked-by: Dan Williams 
Cc: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs: ext2: Adding new return type vm_fault_t

2018-04-16T07:52:24+00:00

Use new return type vm_fault_t for page_mkwrite,
pfn_mkwrite and fault handler.

Signed-off-by: Souptick Joarder 
Reviewed-by: Matthew Wilcox 
Signed-off-by: Jan Kara

dax: pass detailed error code from dax_iomap_fault()

2018-01-07T21:38:43+00:00

Ext4 needs to pass through error from its iomap handler to the page
fault handler so that it can properly detect ENOSPC and force
transaction commit and retry the fault (and block allocation). Add
argument to dax_iomap_fault() for passing such error.

Reviewed-by: Ross Zwisler 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o