bcachefs: Prefer struct_size over open coded arithmetic

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].

As the "op" variable is a pointer to "struct promote_op" and this
structure ends in a flexible array:

struct promote_op {
[...]
struct bio_vec bi_inline_vecs[];
};

and the "t" variable is a pointer to "struct journal_seq_blacklist_table"
and this structure also ends in a flexible array:

struct journal_seq_blacklist_table {
[...]
struct journal_seq_blacklist_table_entry {
u64 start;
u64 end;
bool dirty;
} entries[];
};

the preferred way in the kernel is to use the struct_size() helper to
do the arithmetic instead of the argument "size + size * count" in the
kzalloc() functions.

This way, the code is more readable and safer.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Erick Archer <erick.archer@gmx.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: improve checksum error messages

new helpers:
- bch2_csum_to_text()
- bch2_csum_err_msg()

standardize our checksum error messages a bit, and print out the
checksums a bit more nicely.

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

bcachefs: Improve the nopromote tracepoint

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

bcachefs: Use GFP_KERNEL for promote allocations

We already have btree locks dropped here - no need for GFP_NOFS.

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

bcachefs: Replace zero-length arrays with flexible-array members

Fake flexible arrays (zero-length and one-element arrays) are
deprecated, and should be replaced by flexible-array members.

So, replace zero-length arrays with flexible-array members
in multiple structures.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
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: Data update path won't accidentaly grow replicas

Previously, there was a bug where if an extent had greater durability
than required (because we needed to move a durability=1 pointer and
ended up putting it on a durability 2 device), we would submit a write
for replicas=2 - the durability of the pointer being rewritten - instead
of the number of replicas required to bring it back up to the
data_replicas option.

This, plus the allocation path sometimes allocating on a greater
durability device than requested, meant that extents could continue
having more and more replicas added as they were being rewritten.

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

bcachefs: bch2_ec_read_extent() now takes btree_trans

We're not supposed to have more than one btree_trans at a time in a
given thread - that causes recursive locking deadlocks.

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

bcachefs: Add IO error counts to bch_member

We now track IO errors per device since filesystem creation.

IO error counts can be viewed in sysfs, or with the 'bcachefs
show-super' command.

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

bcachefs: Fixes for building in userspace

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: remove duplicated assignment to variable offset_into_extent

Variable offset_into_extent is being assigned to zero and a few
statements later it is being re-assigned again to the save value.
The second assignment is redundant and can be removed. Cleans up
clang-scan build warning:

fs/bcachefs/io.c:2722:3: warning: Value stored to 'offset_into_extent'
is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: trace_read_nopromote()

Add a tracepoint to print the reason a read wasn't promoted.

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>