bcachefs: Add error messages to logged ops fns

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

bcachefs: opts->compression can now also be applied in the background

The "apply this compression method in the background" paths now use the
compression option if background_compression is not set; this means that
setting or changing the compression option will cause existing data to
be compressed accordingly in the background.

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

bcachefs: bkey_for_each_ptr() now declares loop iter

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

bcachefs: clean up some dead fallocate code

The have_reservation local variable in bch2_extent_fallocate() is
initialized to false and set to true further down in the function.
Between this two points, one branch of code checks for negative
value and one for positive, and nothing ever checks the variable
after it is set to true. Clean up some of the unnecessary logic and
code.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Make sure allocation failure errors are logged

The previous patch fixed a bug in allocation path error handling, and it
would've been noticed sooner had it been logged properly.

Generally speaking, errors that shouldn't happen in normal operation and
are being returned up the stack should be logged: the write path was
already logging IO errors, but non IO errors were missed.

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

bcachefs: Rename BTREE_INSERT flags

BTREE_INSERT flags are actually transaction commit flags - rename them
for clarity.

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

bcachefs: Fix an integer overflow

Fixes:

bcachefs (e7fdc10e-54a3-49d9-bd0c-390370889d84): disk usage increased 4294967296 more than 2823707312 sectors reserved)
transaction updates for __bchfs_fallocate journal seq 467859
update: btree=extents cached=0 bch2_trans_update+0x4e8/0x540
old u64s 5 type deleted 536925940:3559337304:4294967283 len 0 ver 0
new u64s 6 type reservation 536925940:3559337304:4294967283 len 3559337304 ver 0: generation 0 replicas 2
update: btree=inodes cached=1 bch2_extent_update_i_size_sectors+0x305/0x3b0
old u64s 19 type inode_v3 0:536925940:4294967283 len 0 ver 0: mode 100600 flags 15300000 journal_seq 467859 bi_size 0 bi_sectors 0 bi_version 0 bi_atime 40905301656446 bi_ctime 40905301656446 bi_mtime 40905301656446 bi_otime 40905301656446 bi_uid 0 bi_gid 0 bi_nlink 0 bi_generation 0 bi_dev 0 bi_data_checksum 0 bi_compression 0 bi_project 0 bi_background_compression 0 bi_data_replicas 0 bi_promote_target 0 bi_foreground_target 0 bi_background_target 0 bi_erasure_code 0 bi_fields_set 0 bi_dir 1879048193 bi_dir_offset 3384856038735393365 bi_subvol 0 bi_parent_subvol 0 bi_nocow 0
new u64s 19 type inode_v3 0:536925940:4294967283 len 0 ver 0: mode 100600 flags 15300000 journal_seq 467859 bi_size 0 bi_sectors 3559337304 bi_version 0 bi_atime 40905301656446 bi_ctime 40905301656446 bi_mtime 40905301656446 bi_otime 40905301656446 bi_uid 0 bi_gid 0 bi_nlink 0 bi_generation 0 bi_dev 0 bi_data_checksum 0 bi_compression 0 bi_project 0 bi_background_compression 0 bi_data_replicas 0 bi_promote_target 0 bi_foreground_target 0 bi_background_target 0 bi_erasure_code 0 bi_fields_set 0 bi_dir 1879048193 bi_dir_offset 3384856038735393365 bi_subvol 0 bi_parent_subvol 0 bi_nocow 0

Kernel panic - not syncing: bcachefs (e7fdc10e-54a3-49d9-bd0c-390370889d84): panic after error
CPU: 4 PID: 5154 Comm: rsync Not tainted 6.5.9-gateway-gca1614174cc0-dirty #1
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X570 Phantom Gaming 4, BIOS P4.20 08/02/2021
Call Trace:
<TASK>
dump_stack_lvl+0x5a/0x90
panic+0x105/0x300
? console_unlock+0xf1/0x130
? bch2_printbuf_exit+0x16/0x30
? srso_return_thunk+0x5/0x10
bch2_inconsistent_error+0x6f/0x80
bch2_trans_fs_usage_apply+0x279/0x3d0
__bch2_trans_commit+0x112a/0x1df0
? bch2_extent_update+0x13a/0x1d0
bch2_extent_update+0x13a/0x1d0
bch2_extent_fallocate+0x58e/0x740
bch2_fallocate_dispatch+0xb7c/0x1030
? do_filp_open+0xa0/0x140
vfs_fallocate+0x18e/0x1d0
__x64_sys_fallocate+0x46/0x70
do_syscall_64+0x48/0xa0
? exit_to_user_mode_prepare+0x4d/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
RIP: 0033:0x7fc85d91bbb3
Code: 64 89 02 b8 ff ff ff ff eb bd 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 80 3d 31 da 0d 00 00 49 89 ca 74 14 b8 1d 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5d c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 10

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

bcachefs: rebalance_work

This adds a new btree, rebalance_work, to eliminate scanning required
for finding extents that need work done on them in the background - i.e.
for the background_target and background_compression options.

rebalance_work is a bitset btree, where a KEY_TYPE_set corresponds to an
extent in the extents or reflink btree at the same pos.

A new extent field is added, bch_extent_rebalance, which indicates that
this extent has work that needs to be done in the background - and which
options to use. This allows per-inode options to be propagated to
indirect extents - at least in some circumstances. In this patch,
changing IO options on a file will not propagate the new options to
indirect extents pointed to by that file.

Updating (setting/clearing) the rebalance_work btree is done by the
extent trigger, which looks at the bch_extent_rebalance field.

Scanning is still requrired after changing IO path options - either just
for a given inode, or for the whole filesystem. We indicate that
scanning is required by adding a KEY_TYPE_cookie key to the
rebalance_work btree: the cookie counter is so that we can detect that
scanning is still required when an option has been flipped mid-way
through an existing scan.

Future possible work:
- Propagate options to indirect extents when being changed
- Add other IO path options - nr_replicas, ec, to rebalance_work so
they can be applied in the background when they change
- Add a counter, for bcachefs fs usage output, showing the pending
amount of rebalance work: we'll probably want to do this after the
disk space accounting rewrite (moving it to a new btree)

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

bcachefs: snapshot_create_lock

Add a new lock for snapshot creation - this addresses a few races with
logged operations and snapshot deletion.

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

bcachefs: Fix -Wself-assign

Fixes the following observed error reported by Nathan on IRC.

fs/bcachefs/io_misc.c:467:6: error: explicitly assigning value of
variable of type 'int' to itself [-Werror,-Wself-assign]
467 | ret = ret;
| ~~~ ^ ~~~

Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Heap allocate btree_trans

We're using more stack than we'd like in a number of functions, and
btree_trans is the biggest object that we stack allocate.

But we have to do a heap allocatation to initialize it anyways, so
there's no real downside to heap allocating the entire thing.

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

bcachefs: Log finsert/fcollapse operations

Now that we have the logged operations btree, we can make
finsert/fcollapse atomic w.r.t. unclean shutdown as well.

This adds bch_logged_op_finsert to represent the state of an finsert or
fcollapse, which is a bit more complicated than truncate since we need
to track our position in the "shift extents" operation.

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

bcachefs: Log truncate operations

Previously, we guaranteed atomicity of truncate after unclean shutdown
with the BCH_INODE_I_SIZE_DIRTY flag - which required a full scan of the
inodes btree.

Recently the deleted inodes btree was added so that we no longer have to
scan for deleted inodes, but truncate was unfinished and that change
left it broken.

This patch uses the new logged operations btree to fix truncate
atomicity; we now log an operation that can be replayed at the start of
a truncate.

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

bcachefs: New io_misc.c helpers

This pulls the non vfs specific parts of truncate and finsert/fcollapse
out of fs-io.c, and moves them to io_misc.c.

This is prep work for logging these operations, to make them atomic in
the event of a crash.

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

bcachefs: Break up io.c

More reorganization, this splits up io.c into
- io_read.c
- io_misc.c - fallocate, fpunch, truncate
- io_write.c

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