mds: use explicitly sized types for network and disk encoding

[lxbsz]

The size of 'unsigned' type maybe not different from different OSes. And we should always use explicitly sized type.

Fixes: https://tracker.ceph.com/issues/63552

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[dparmar18]

Migrator and Mutation codes too can take this change

Migrator.h:    export_base_t(dirfrag_t df, mds_rank_t d, unsigned c, uint64_t g) :
Migrator.h:    unsigned pending_children;
Migrator.h:  unsigned num_locking_exports = 0; // exports in locking state (approx_size == 0)

Mutation.h:    LockOp(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) :
Mutation.h:    mutable unsigned flags;
Mutation.h:  lock_iterator emplace_lock(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) {

[dparmar18]

and i think some what server code could also be fixed

ceph/src/mds/Server.h

Lines 496 to 507 in 70d8c5b

	void _readdir_diff(
	utime_t now,
	MDRequestRef& mdr,
	CInode* diri,
	CDir* dir,
	SnapRealm* realm,
	unsigned max_entries,
	int bytes_left,
	const std::string& offset_str,
	uint32_t offset_hash,
	unsigned req_flags,
	bufferlist& dirbl);

[lxbsz]

and i think some what server code could also be fixed

ceph/src/mds/Server.h

Lines 496 to 507 in 70d8c5b

	void _readdir_diff(
	utime_t now,
	MDRequestRef& mdr,
	CInode* diri,
	CDir* dir,
	SnapRealm* realm,
	unsigned max_entries,
	int bytes_left,
	const std::string& offset_str,
	uint32_t offset_hash,
	unsigned req_flags,
	bufferlist& dirbl);

This should be fine, because we won't do disk encoding directly with them.

[lxbsz]

Migrator and Mutation codes too can take this change

Migrator.h:    export_base_t(dirfrag_t df, mds_rank_t d, unsigned c, uint64_t g) :
Migrator.h:    unsigned pending_children;
Migrator.h:  unsigned num_locking_exports = 0; // exports in locking state (approx_size == 0)

Mutation.h:    LockOp(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) :
Mutation.h:    mutable unsigned flags;
Mutation.h:  lock_iterator emplace_lock(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) {

@dparmar18 I didn't see anywhere is encoding this for network or disk, did I miss something here ?

[mchangir]

ILP32 and LP64 architectures all implement unsigned as unsigned int a.k.a. uint32_t
could you point where this standard isn't being followed ?

however, I agree its always a good idea to specify the data size upfront during serialization/deserialization

[lxbsz]

I couldn't tell exactly where. I just found this when I was coding the kclient patches and googled about this. It's said in some platform or OS it maybe different. As @gregsfortytwo mentioned we should always use explicitly sized type in these cases.

[mchangir]

so is uint32_t good enough or is __le32 more appropriate ?

[lxbsz]

The uint32_t is good enough here and the encode() will help switch it to __le32.

[mchangir]

LGTM

[dparmar18]

Migrator and Mutation codes too can take this change

Migrator.h:    export_base_t(dirfrag_t df, mds_rank_t d, unsigned c, uint64_t g) :
Migrator.h:    unsigned pending_children;
Migrator.h:  unsigned num_locking_exports = 0; // exports in locking state (approx_size == 0)

Mutation.h:    LockOp(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) :
Mutation.h:    mutable unsigned flags;
Mutation.h:  lock_iterator emplace_lock(SimpleLock *l, unsigned f=0, mds_rank_t t=MDS_RANK_NONE) {

@dparmar18 I didn't see anywhere is encoding this for network or disk, did I miss something here ?

scrolling through these methods i saw usage of fixed size types in their params hence the comment, but since they play no role in encoding, it doesn't make sense to touch them

[dparmar18]

jenkins test make check arm64

[rishabh-d-dave]

https://tracker.ceph.com/projects/cephfs/wiki/Main#16-Jan-2023