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  1. 06 Aug, 2023 4 commits
    • Christian Brauner's avatar
      fs: rely on ->iterate_shared to determine f_pos locking · 7d84d1b9
      Christian Brauner authored 
      Now that we removed ->iterate we don't need to check for either
->iterate or ->iterate_shared in file_needs_f_pos_lock(). Simply check
for ->iterate_shared instead. This will tell us whether we need to
unconditionally take the lock. Not just does it allow us to avoid
checking f_inode's mode it also actually clearly shows that we're
locking because of readdir.
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
      7d84d1b9
    • Linus Torvalds's avatar
      vfs: get rid of old '->iterate' directory operation · 3e327154
      Linus Torvalds authored 
      All users now just use '->iterate_shared()', which only takes the
directory inode lock for reading.

Filesystems that never got convered to shared mode now instead use a
wrapper that drops the lock, re-takes it in write mode, calls the old
function, and then downgrades the lock back to read mode.

This way the VFS layer and other callers no longer need to care about
filesystems that never got converted to the modern era.

The filesystems that use the new wrapper are ceph, coda, exfat, jfs,
ntfs, ocfs2, overlayfs, and vboxsf.

Honestly, several of them look like they really could just iterate their
directories in shared mode and skip the wrapper entirely, but the point
of this change is to not change semantics or fix filesystems that
haven't been fixed in the last 7+ years, but to finally get rid of the
dual iterators.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
      3e327154
    • Linus Torvalds's avatar
      proc: fix missing conversion to 'iterate_shared' · 0a2c2baa
      Linus Torvalds authored 
      I'm looking at the directory handling due to the discussion about f_pos
locking (see commit 79796425: "file: reinstate f_pos locking
optimization for regular files"), and wanting to clean that up.

And one source of ugliness is how we were supposed to move filesystems
over to the '->iterate_shared()' function that only takes the inode lock
for reading many many years ago, but several filesystems still use the
bad old '->iterate()' that takes the inode lock for exclusive access.

See commit 61922694 ("introduce a parallel variant of ->iterate()")
that also added some documentation stating

      Old method is only used if the new one is absent; eventually it will
      be removed.  Switch while you still can; the old one won't stay.

and that was back in April 2016.  Here we are, many years later, and the
old version is still clearly sadly alive and well.

Now, some of those old style iterators are probably just because the
filesystem may end up having per-inode mutable data that it uses for
iterating a directory, but at least one case is just a mistake.

Al switched over most filesystems to use '->iterate_shared()' back when
it was introduced.  In particular, the /proc filesystem was converted as
one of the first ones in commit f50752ea ("switch all procfs
directories ->iterate_shared()").

But then later one new user of '->iterate()' was then re-introduced by
commit 6d9c939d ("procfs: add smack subdir to attrs").

And that's clearly not what we wanted, since that new case just uses the
same 'proc_pident_readdir()' and 'proc_pident_lookup()' helper functions
that other /proc pident directories use, and they are most definitely
safe to use with the inode lock held shared.

So just fix it.

This still leaves a fair number of oddball filesystems using the
old-style directory iterator (ceph, coda, exfat, jfs, ntfs, ocfs2,
overlayfs, and vboxsf), but at least we don't have any remaining in the
core filesystems.

I'm going to add a wrapper function that just drops the read-lock and
takes it as a write lock, so that we can clean up the core vfs layer and
make all the ugly 'this filesystem needs exclusive inode locking' be
just filesystem-internal warts.

I just didn't want to make that conversion when we still had a core user
left.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
      0a2c2baa
    • Aleksa Sarai's avatar
      open: make RESOLVE_CACHED correctly test for O_TMPFILE · a0fc452a
      Aleksa Sarai authored 
      O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old
fast-path check for RESOLVE_CACHED would reject all users passing
O_DIRECTORY with -EAGAIN, when in fact the intended test was to check
for __O_TMPFILE.

Cc: stable@vger.kernel.org # v5.12+
Fixes: 99668f61 ("fs: expose LOOKUP_CACHED through openat2() RESOLVE_CACHED")
Signed-off-by: default avatarAleksa Sarai <cyphar@cyphar.com>
Message-Id: <20230806-resolve_cached-o_tmpfile-v1-1-7ba16308465e@cyphar.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
      a0fc452a
  3. 05 Aug, 2023 1 commit
    • Linus Torvalds's avatar
      Merge tag 'hyperv-fixes-signed-20230804' of... · 024ff300
      Linus Torvalds authored 
      Merge tag 'hyperv-fixes-signed-20230804' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv fixes from Wei Liu:

 - Fix a bug in a python script for Hyper-V (Ani Sinha)

 - Workaround a bug in Hyper-V when IBT is enabled (Michael Kelley)

 - Fix an issue parsing MP table when Linux runs in VTL2 (Saurabh
   Sengar)

 - Several cleanup patches (Nischala Yelchuri, Kameron Carr, YueHaibing,
   ZhiHu)

* tag 'hyperv-fixes-signed-20230804' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  Drivers: hv: vmbus: Remove unused extern declaration vmbus_ontimer()
  x86/hyperv: add noop functions to x86_init mpparse functions
  vmbus_testing: fix wrong python syntax for integer value comparison
  x86/hyperv: fix a warning in mshyperv.h
  x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction
  x86/hyperv: Improve code for referencing hyperv_pcpu_input_arg
  Drivers: hv: Change hv_free_hyperv_page() to take void * argument
      024ff300
  5. 04 Aug, 2023 10 commits
  7. 03 Aug, 2023 25 commits
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