Unverified Commit b6be3714 authored by Jeff Layton's avatar Jeff Layton Committed by Christian Brauner
Browse files

filelock: convert __locks_insert_block, conflict and deadlock checks to use file_lock_core 



Have both __locks_insert_block and the deadlock and conflict checking
functions take a struct file_lock_core pointer instead of a struct
file_lock one. Also, change posix_locks_deadlock to return bool.

Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-25-c6129007ee8d@kernel.org


Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 1a62c22a

fs/locks.c

+72 −60
Original line number Diff line number Diff line
@@ -757,39 +757,41 @@ EXPORT_SYMBOL(locks_delete_block); 
 * waiters, and add beneath any waiter that blocks the new waiter.

 * Thus wakeups don't happen until needed.

 */

static void __locks_insert_block(struct file_lock *blocker,

				 struct file_lock *waiter,

				 bool conflict(struct file_lock *,

					       struct file_lock *))

static void __locks_insert_block(struct file_lock *blocker_fl,

				 struct file_lock *waiter_fl,

				 bool conflict(struct file_lock_core *,

					       struct file_lock_core *))

{

	struct file_lock *fl;

	BUG_ON(!list_empty(&waiter->c.flc_blocked_member));

	struct file_lock_core *blocker = &blocker_fl->c;

	struct file_lock_core *waiter = &waiter_fl->c;

	struct file_lock_core *flc;



	BUG_ON(!list_empty(&waiter->flc_blocked_member));

new_blocker:

	list_for_each_entry(fl, &blocker->c.flc_blocked_requests,

			    c.flc_blocked_member)

		if (conflict(fl, waiter)) {

			blocker =  fl;

	list_for_each_entry(flc, &blocker->flc_blocked_requests, flc_blocked_member)

		if (conflict(flc, waiter)) {

			blocker =  flc;

			goto new_blocker;

		}

	waiter->c.flc_blocker = blocker;

	list_add_tail(&waiter->c.flc_blocked_member,

		      &blocker->c.flc_blocked_requests);

	if ((blocker->c.flc_flags & (FL_POSIX|FL_OFDLCK)) == FL_POSIX)

		locks_insert_global_blocked(&waiter->c);

	waiter->flc_blocker = file_lock(blocker);

	list_add_tail(&waiter->flc_blocked_member,

		      &blocker->flc_blocked_requests);



	if ((blocker->flc_flags & (FL_POSIX|FL_OFDLCK)) == (FL_POSIX|FL_OFDLCK))

		locks_insert_global_blocked(waiter);



	/* The requests in waiter->fl_blocked are known to conflict with

	/* The requests in waiter->flc_blocked are known to conflict with

	 * waiter, but might not conflict with blocker, or the requests

	 * and lock which block it.  So they all need to be woken.

	 */

	__locks_wake_up_blocks(&waiter->c);

	__locks_wake_up_blocks(waiter);

}



/* Must be called with flc_lock held. */

static void locks_insert_block(struct file_lock *blocker,

			       struct file_lock *waiter,

			       bool conflict(struct file_lock *,

					     struct file_lock *))

			       bool conflict(struct file_lock_core *,

					     struct file_lock_core *))

{

	spin_lock(&blocked_lock_lock);

	__locks_insert_block(blocker, waiter, conflict);
@@ -846,12 +848,12 @@ locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose) 
/* Determine if lock sys_fl blocks lock caller_fl. Common functionality

 * checks for shared/exclusive status of overlapping locks.

 */

static bool locks_conflict(struct file_lock *caller_fl,

			   struct file_lock *sys_fl)

static bool locks_conflict(struct file_lock_core *caller_flc,

			   struct file_lock_core *sys_flc)

{

	if (lock_is_write(sys_fl))

	if (sys_flc->flc_type == F_WRLCK)

		return true;

	if (lock_is_write(caller_fl))

	if (caller_flc->flc_type == F_WRLCK)

		return true;

	return false;

}
@@ -859,20 +861,23 @@ static bool locks_conflict(struct file_lock *caller_fl, 
/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific

 * checking before calling the locks_conflict().

 */

static bool posix_locks_conflict(struct file_lock *caller_fl,

				 struct file_lock *sys_fl)

static bool posix_locks_conflict(struct file_lock_core *caller_flc,

				 struct file_lock_core *sys_flc)

{

	struct file_lock *caller_fl = file_lock(caller_flc);

	struct file_lock *sys_fl = file_lock(sys_flc);



	/* POSIX locks owned by the same process do not conflict with

	 * each other.

	 */

	if (posix_same_owner(&caller_fl->c, &sys_fl->c))

	if (posix_same_owner(caller_flc, sys_flc))

		return false;



	/* Check whether they overlap */

	if (!locks_overlap(caller_fl, sys_fl))

		return false;



	return locks_conflict(caller_fl, sys_fl);

	return locks_conflict(caller_flc, sys_flc);

}



/* Determine if lock sys_fl blocks lock caller_fl. Used on xx_GETLK
@@ -881,28 +886,31 @@ static bool posix_locks_conflict(struct file_lock *caller_fl, 
static bool posix_test_locks_conflict(struct file_lock *caller_fl,

				      struct file_lock *sys_fl)

{

	struct file_lock_core *caller = &caller_fl->c;

	struct file_lock_core *sys = &sys_fl->c;



	/* F_UNLCK checks any locks on the same fd. */

	if (lock_is_unlock(caller_fl)) {

		if (!posix_same_owner(&caller_fl->c, &sys_fl->c))

		if (!posix_same_owner(caller, sys))

			return false;

		return locks_overlap(caller_fl, sys_fl);

	}

	return posix_locks_conflict(caller_fl, sys_fl);

	return posix_locks_conflict(caller, sys);

}



/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific

 * checking before calling the locks_conflict().

 */

static bool flock_locks_conflict(struct file_lock *caller_fl,

				 struct file_lock *sys_fl)

static bool flock_locks_conflict(struct file_lock_core *caller_flc,

				 struct file_lock_core *sys_flc)

{

	/* FLOCK locks referring to the same filp do not conflict with

	 * each other.

	 */

	if (caller_fl->c.flc_file == sys_fl->c.flc_file)

	if (caller_flc->flc_file == sys_flc->flc_file)

		return false;



	return locks_conflict(caller_fl, sys_fl);

	return locks_conflict(caller_flc, sys_flc);

}



void
@@ -980,25 +988,27 @@ EXPORT_SYMBOL(posix_test_lock); 


#define MAX_DEADLK_ITERATIONS 10



/* Find a lock that the owner of the given block_fl is blocking on. */

static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)

/* Find a lock that the owner of the given @blocker is blocking on. */

static struct file_lock_core *what_owner_is_waiting_for(struct file_lock_core *blocker)

{

	struct file_lock *fl;

	struct file_lock_core *flc;



	hash_for_each_possible(blocked_hash, fl, c.flc_link, posix_owner_key(&block_fl->c)) {

		if (posix_same_owner(&fl->c, &block_fl->c)) {

			while (fl->c.flc_blocker)

				fl = fl->c.flc_blocker;

			return fl;

	hash_for_each_possible(blocked_hash, flc, flc_link, posix_owner_key(blocker)) {

		if (posix_same_owner(flc, blocker)) {

			while (flc->flc_blocker)

				flc = &flc->flc_blocker->c;

			return flc;

		}

	}

	return NULL;

}



/* Must be called with the blocked_lock_lock held! */

static int posix_locks_deadlock(struct file_lock *caller_fl,

static bool posix_locks_deadlock(struct file_lock *caller_fl,

				 struct file_lock *block_fl)

{

	struct file_lock_core *caller = &caller_fl->c;

	struct file_lock_core *blocker = &block_fl->c;

	int i = 0;



	lockdep_assert_held(&blocked_lock_lock);
@@ -1007,16 +1017,16 @@ static int posix_locks_deadlock(struct file_lock *caller_fl, 
	 * This deadlock detector can't reasonably detect deadlocks with

	 * FL_OFDLCK locks, since they aren't owned by a process, per-se.

	 */

	if (caller_fl->c.flc_flags & FL_OFDLCK)

		return 0;

	if (caller->flc_flags & FL_OFDLCK)

		return false;



	while ((block_fl = what_owner_is_waiting_for(block_fl))) {

	while ((blocker = what_owner_is_waiting_for(blocker))) {

		if (i++ > MAX_DEADLK_ITERATIONS)

			return 0;

		if (posix_same_owner(&caller_fl->c, &block_fl->c))

			return 1;

			return false;

		if (posix_same_owner(caller, blocker))

			return true;

	}

	return 0;

	return false;

}



/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
@@ -1071,7 +1081,7 @@ static int flock_lock_inode(struct inode *inode, struct file_lock *request) 


find_conflict:

	list_for_each_entry(fl, &ctx->flc_flock, c.flc_list) {

		if (!flock_locks_conflict(request, fl))

		if (!flock_locks_conflict(&request->c, &fl->c))

			continue;

		error = -EAGAIN;

		if (!(request->c.flc_flags & FL_SLEEP))
@@ -1140,7 +1150,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, 
	 */

	if (request->c.flc_type != F_UNLCK) {

		list_for_each_entry(fl, &ctx->flc_posix, c.flc_list) {

			if (!posix_locks_conflict(request, fl))

			if (!posix_locks_conflict(&request->c, &fl->c))

				continue;

			if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable

				&& (*fl->fl_lmops->lm_lock_expirable)(fl)) {
@@ -1442,23 +1452,25 @@ static void time_out_leases(struct inode *inode, struct list_head *dispose) 
	}

}



static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)

static bool leases_conflict(struct file_lock_core *lc, struct file_lock_core *bc)

{

	bool rc;

	struct file_lock *lease = file_lock(lc);

	struct file_lock *breaker = file_lock(bc);



	if (lease->fl_lmops->lm_breaker_owns_lease

			&& lease->fl_lmops->lm_breaker_owns_lease(lease))

		return false;

	if ((breaker->c.flc_flags & FL_LAYOUT) != (lease->c.flc_flags & FL_LAYOUT)) {

	if ((bc->flc_flags & FL_LAYOUT) != (lc->flc_flags & FL_LAYOUT)) {

		rc = false;

		goto trace;

	}

	if ((breaker->c.flc_flags & FL_DELEG) && (lease->c.flc_flags & FL_LEASE)) {

	if ((bc->flc_flags & FL_DELEG) && (lc->flc_flags & FL_LEASE)) {

		rc = false;

		goto trace;

	}



	rc = locks_conflict(breaker, lease);

	rc = locks_conflict(bc, lc);

trace:

	trace_leases_conflict(rc, lease, breaker);

	return rc;
@@ -1468,12 +1480,12 @@ static bool 
any_leases_conflict(struct inode *inode, struct file_lock *breaker)

{

	struct file_lock_context *ctx = inode->i_flctx;

	struct file_lock *fl;

	struct file_lock_core *flc;



	lockdep_assert_held(&ctx->flc_lock);



	list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {

		if (leases_conflict(fl, breaker))

	list_for_each_entry(flc, &ctx->flc_lease, flc_list) {

		if (leases_conflict(flc, &breaker->c))

			return true;

	}

	return false;
@@ -1529,7 +1541,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) 
	}



	list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, c.flc_list) {

		if (!leases_conflict(fl, new_fl))

		if (!leases_conflict(&fl->c, &new_fl->c))

			continue;

		if (want_write) {

			if (fl->c.flc_flags & FL_UNLOCK_PENDING)