Our proliferation of memalloc_*_{save,restore} APIs is getting a bit
silly, this adds a generic version and converts the existing
save/restore functions to wrappers.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: linux-mm@kvack.org
Acked-by: Vlastimil Babka <vbabka@suse.cz>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Going to be adding more code here for checking subvol structure.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Repurposing standard error codes in bcachefs code is banned in new code,
and we need to get rid of the remaining ones - private error codes give
us much better error messages.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

WQ_UNBOUND with max_active 1 means ordered workqueue, but we don't
actually need or want ordered semantics - and probably want a higher
concurrency limit anyways.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Need to fix this oversight for the new FS_IOC_(GET|SET)UUID ioctls.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

switch the statfs code from something horrible and open coded to the
more standard uuid_to_fsid()
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Files within a subvolume cannot be renamed into another subvolume, but
subvolumes themselves were intended to be.

This implements subvolume renaming - we need to ensure that there's only
a single dirent that points to a subvolume key (not multiple versions in
different snapshots), and we need to ensure that dirent.d_parent_subol
and inode.bi_parent_subvol are updated.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

btree_and_journal_iter is old code that we want to get rid of, but we're
not ready to yet.

lack of btree node prefetching is, it turns out, a real performance
issue for fsck on spinning rust, so - add it.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

we now always have a btree_trans when using a btree_and_journal_iter;
prep work for adding prefetching to btree_and_journal_iter
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Recently a severe performance regression was discovered, which bisected
to

  a6548c8b bcachefs: Avoid flushing the journal in the discard path

It turns out the old behaviour, which issued excessive journal flushes,
worked around a performance issue where queueing delays would cause the
journal to not be able to write quickly enough and stall.

The journal flushes masked the issue because they periodically flushed
the device write cache, reducing write latency for non flushes.

This patch reworks the journalling code to allow more than one
(non-flush) write to be in flight at a time. With this patch, doing 4k
random writes and an iodepth of 128, we are now able to hit 560k iops to
a Samsung 970 EVO Plus - previously, we were stuck in the ~200k range.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Prep work for having multiple journal writes in flight.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Prep work for having multiple journal writes in flight.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This gives us a way to record the date and time every journal entry was
written - useful for debugging.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Eliminates some error paths - no longer have a hardcoded
BCH_REPLICAS_MAX limit.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Drop an unnecessary bch2_subvolume_get_snapshot() call, and drop the __
from the name - this is a normal interface.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Minor renaming for clarity, bit of refactoring.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Most bcachefs workqueues are used for completions, and should be
WQ_HIGHPRI - this helps reduce queuing delays, we want to complete
quickly once we can no longer signal backpressure by blocking.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

For DT_SUBVOL, we now print both parent and child subvol IDs.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Previously, any time we failed to get a journal reservation we'd retry,
with the journal lock held; but this isn't necessary given
wait_event()/wake_up() ordering.

This avoids performance cliffs when the journal starts to get backed up
and lock contention shoots up.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We don't want journal write completions to be blocked behind btree
transactions - io_complete_wq is used for btree updates after data and
metadata writes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When we are checking whether a subvolume is empty in the specified snapshot,
entries that do not belong to this subvolume should be skipped.

This fixes the following case:

    $ bcachefs subvolume create ./sub
    $ cd sub
    $ bcachefs subvolume create ./sub2
    $ bcachefs subvolume snapshot . ./snap
    $ ls -a snap
    . ..
    $ rmdir snap
    rmdir: failed to remove 'snap': Directory not empty

As Kent suggested, we pass 0 in may_delete_deleted_inode() to ignore subvols
in the subvol we are checking, because inode.bi_subvol is only set on
subvolume roots, and we can't go through every inode in the subvolume and
change bi_subvol when taking a snapshot. It makes the check less strict, but
that's ok, the rest of fsck will still catch it.
Signed-off-by: Guoyu Ou <benogy@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We were failing to set path->uptodate when reaching the end of a btree
node iterator, causing the new prefetch code for backpointers gc to go
into an infinite loop.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

validate_bset_keys() never properly validated k->u64s; it checked if it
was 0, but not if it was smaller than keys for the given packed format;
this fixes that small oversight.

This patch was backported, so it's adding quite a few error enums so
that they don't get renumbered and we don't have confusing gaps.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We don't know where the superblock and journal lives on offline devices;
that means if a device is offline fsck can't check those buckets.

Previously, fsck would incorrectly clear bucket data types for those
buckets on offline devices; now we just use the previous state.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When a btree root is unreadable, we still might be able to get some data
back by replaying what's in the journal. Previously though, we got
confused when journal replay would attempt to replay a key for a level
that didn't exist.

This adds bch2_btree_increase_depth(), so that journal replay can handle
this.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

check_inode_deleted_list() returns true if the inode is on the deleted
list; check_inode() was checking the return code incorrectly.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds an option to disable kicking out devices when splitbrain is
detected - it seems there's some issues with splitbrain detection and
we're kicking out devices erronously.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We need to be able to iterate over extent ptrs that may be corrupted in
order to print them - this fixes a bug where we'd pop an assert in
bch2_bkey_durability_safe().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_journal_seq_blacklist_add() was bugged when the new entry
overlapped with multiple existing entries, and it also assumed new
entries are being added in increasing order.

This is true on any sane filesystem, but when trying to recover from
very badly mangled filesystems we might end up with the journal sequence
number rewinding vs. what the blacklist list knows about - easiest to
just handle that here.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

There is a null-ptr-deref issue reported by kasan:

  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  Call Trace:
    <TASK>
    bch2_fs_alloc+0x1092/0x2170 [bcachefs]
    bch2_fs_open+0x683/0xe10 [bcachefs]
    ...

When initializing the name of bch_fs, it needs to dynamically alloc memory
to meet the length of the name. However, when name allocation failed, it
will cause a null-ptr-deref access exception in subsequent string copy.

Fix this issue by checking if name allocation is successful.

Fixes: 401ec4db ("bcachefs: Printbuf rework")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Pull bcachefs fixes from Kent Overstreet:
 "Some more mostly boring fixes, but some not

  User reported ones:

   - the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty
     performance bug; user reported an untar initially taking two
     seconds and then ~2 minutes

   - kill a __GFP_NOFAIL in the buffered read path; this was a leftover
     from the trickier fix to kill __GFP_NOFAIL in readahead, where we
     can't return errors (and have to silently truncate the read
     ourselves).

     bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
     filesystems because our folio state is just barely too big, 2MB
     hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.

     additionally, the flags argument was just buggy, we weren't
     supplying GFP_KERNEL previously (!)"

* tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs:
  bcachefs: fix bch2_save_backtrace()
  bcachefs: Fix check_snapshot() memcpy
  bcachefs: Fix bch2_journal_flush_device_pins()
  bcachefs: fix iov_iter count underflow on sub-block dio read
  bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree
  bcachefs: Kill __GFP_NOFAIL in buffered read path
  bcachefs: fix backpointer_to_text() when dev does not exist