linux.git/fs/gfs2, branch v5.13

Revert "gfs2: Fix mmap locking for write faults"

2021-06-01T21:16:42+00:00

This reverts commit b7f55d928e75557295c1ac280c291b738905b6fb.

As explained by Linus in [*], write faults on a mmap region are reads
from a filesysten point of view, so taking the inode glock exclusively
on write faults is incorrect.

Instead, when a page is marked writable, the .page_mkwrite vm operation
will be called, which is where the exclusive lock taking needs to
happen.  I got this wrong because of a broken test case that made me
believe .page_mkwrite isn't getting called when it actually is.

[*] https://lore.kernel.org/lkml/CAHk-=wj8EWr_D65i4oRSj2FTbrc6RdNydNNCGxeabRnwtoU=3Q@mail.gmail.com/

Signed-off-by: Andreas Gruenbacher

gfs2: Fix use-after-free in gfs2_glock_shrink_scan

2021-05-31T10:03:28+00:00

The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to
remove the glock from the lru list in __gfs2_glock_put().

On the shrink scan path, the same flag is cleared under lru_lock but because
of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the
put side can be made without deleting the glock from the lru list.

Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to
ensure correct behavior on both sides - clear GLF_LRU after list_del under
lru_lock.

Reported-by: syzbot 
Signed-off-by: Hillf Danton 
Signed-off-by: Andreas Gruenbacher

gfs2: Fix mmap locking for write faults

2021-05-21T03:16:38+00:00

When a write fault occurs, we need to take the inode glock of the underlying
inode in exclusive mode.  Otherwise, there's no guarantee that the dirty page
will be written back to disk.

Signed-off-by: Andreas Gruenbacher

gfs2: Clean up revokes on normal withdraws

2021-05-20T11:31:37+00:00

Before this patch, the system ail lists were cleaned up if the logd
process withdrew, but on other withdraws, they were not cleaned up.
This included the cleaning up of the revokes as well.

This patch reorganizes things a bit so that all withdraws (not just logd)
clean up the ail lists, including any pending revokes.

Signed-off-by: Bob Peterson 
Signed-off-by: Andreas Gruenbacher

gfs2: fix a deadlock on withdraw-during-mount

2021-05-20T11:31:37+00:00

Before this patch, gfs2 would deadlock because of the following
sequence during mount:

mount
   gfs2_fill_super
      gfs2_make_fs_rw <--- Detects IO error with glock
         kthread_stop(sdp->sd_quotad_process);
            <--- Blocked waiting for quotad to finish

logd
   Detects IO error and the need to withdraw
   calls gfs2_withdraw
      gfs2_make_fs_ro
         kthread_stop(sdp->sd_quotad_process);
            <--- Blocked waiting for quotad to finish

gfs2_quotad
   gfs2_statfs_sync
      gfs2_glock_wait <---- Blocked waiting for statfs glock to be granted

glock_work_func
   do_xmote <---Detects IO error, can't release glock: blocked on withdraw
      glops->go_inval
      glock_blocked_by_withdraw
         requeue glock work & exit <--- work requeued, blocked by withdraw

This patch makes a special exception for the statfs system inode glock,
which allows the statfs glock UNLOCK to proceed normally. That allows the
quotad daemon to exit during the withdraw, which allows the logd daemon
to exit during the withdraw, which allows the mount to exit.

Signed-off-by: Bob Peterson 
Signed-off-by: Andreas Gruenbacher

gfs2: fix scheduling while atomic bug in glocks

2021-05-20T11:31:37+00:00

Before this patch, in the unlikely event that gfs2_glock_dq encountered
a withdraw, it would do a wait_on_bit to wait for its journal to be
recovered, but it never released the glock's spin_lock, which caused a
scheduling-while-atomic error.

This patch unlocks the lockref spin_lock before waiting for recovery.

Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish")
Cc: stable@vger.kernel.org # v5.7+
Reported-by: Alexander Aring 
Signed-off-by: Bob Peterson 
Signed-off-by: Andreas Gruenbacher

gfs2: Fix I_NEW check in gfs2_dinode_in

2021-05-20T11:31:37+00:00

Patch 4a378d8a0d96 added a new check for I_NEW inodes, but unfortunately
it used the wrong variable, i_flags. This caused GFS2 to withdraw when
gfs2_lookup_by_inum needed to refresh an I_NEW inode. This patch switches
to use the correct variable, i_state.

Fixes: 4a378d8a0d96 ("gfs2: be careful with inode refresh")
Signed-off-by: Bob Peterson 
Signed-off-by: Andreas Gruenbacher

gfs2: Prevent direct-I/O write fallback errors from getting lost

2021-05-20T11:31:36+00:00

When a direct I/O write falls entirely and falls back to buffered I/O and the
buffered I/O fails, the write failed with return value 0 instead of the error
number reported by the buffered I/O. Fix that.

Signed-off-by: Andreas Gruenbacher

mm: introduce and use mapping_empty()

2021-05-05T18:27:19+00:00

Patch series "Remove nrexceptional tracking", v2.

We actually use nrexceptional for very little these days.  It's a minor
pain to keep in sync with nrpages, but the pain becomes much bigger with
the THP patches because we don't know how many indices a shadow entry
occupies.  It's easier to just remove it than keep it accurate.

Also, we save 8 bytes per inode which is nothing to sneeze at; on my
laptop, it would improve shmem_inode_cache from 22 to 23 objects per
16kB, and inode_cache from 26 to 27 objects.  Combined, that saves
a megabyte of memory from a combined usage of 25MB for both caches.
Unfortunately, ext4 doesn't cross a magic boundary, so it doesn't save
any memory for ext4.

This patch (of 4):

Instead of checking the two counters (nrpages and nrexceptional), we can
just check whether i_pages is empty.

Link: https://lkml.kernel.org/r/20201026151849.24232-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20201026151849.24232-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Tested-by: Vishal Verma 
Acked-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'gfs2-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

2021-04-29T17:33:35+00:00

Pull gfs2 updates from Andreas Gruenbacher:

 - Fix some compiler and kernel-doc warnings

 - Various minor cleanups and optimizations

 - Add a new sysfs gfs2 status file with some filesystem wide
   information

* tag 'gfs2-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix fall-through warnings for Clang
  gfs2: Fix a number of kernel-doc warnings
  gfs2: Make gfs2_setattr_simple static
  gfs2: Add new sysfs file for gfs2 status
  gfs2: Silence possible null pointer dereference warning
  gfs2: Turn gfs2_meta_indirect_buffer into gfs2_meta_buffer
  gfs2: Replace gfs2_lblk_to_dblk with gfs2_get_extent
  gfs2: Turn gfs2_extent_map into gfs2_{get,alloc}_extent
  gfs2: Add new gfs2_iomap_get helper
  gfs2: Remove unused variable sb_format
  gfs2: Fix dir.c function parameter descriptions
  gfs2: Eliminate gh parameter from go_xmote_bh func
  gfs2: don't create empty buffers for NO_CREATE