nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity

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

Browse source 
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: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-25-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Jeff Layton 2024-01-31 18:02:06 -05:00 committed by Christian Brauner
parent 1a62c22a15
commit b6be371400
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
1 changed files with 72 additions and 60 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

130
fs/locks.c
View file

@ -757,39 +757,41 @@ EXPORT_SYMBOL(locks_delete_block);
* waiters, and add beneath any waiter that blocks the new waiter. * waiters, and add beneath any waiter that blocks the new waiter.
* Thus wakeups don't happen until needed. * Thus wakeups don't happen until needed.
*/ */
static void __locks_insert_block(struct file_lock *blocker, static void __locks_insert_block(struct file_lock *blocker_fl,
struct file_lock *waiter, struct file_lock *waiter_fl,
bool conflict(struct file_lock *, bool conflict(struct file_lock_core *,
struct file_lock *)) struct file_lock_core *))
{ {
struct file_lock *fl; struct file_lock_core *blocker = &blocker_fl->c;
BUG_ON(!list_empty(&waiter->c.flc_blocked_member)); struct file_lock_core *waiter = &waiter_fl->c;
struct file_lock_core *flc;
BUG_ON(!list_empty(&waiter->flc_blocked_member));
new_blocker: new_blocker:
list_for_each_entry(fl, &blocker->c.flc_blocked_requests, list_for_each_entry(flc, &blocker->flc_blocked_requests, flc_blocked_member)
c.flc_blocked_member) if (conflict(flc, waiter)) {
if (conflict(fl, waiter)) { blocker = flc;
blocker = fl;
goto new_blocker; goto new_blocker;
} }
waiter->c.flc_blocker = blocker; waiter->flc_blocker = file_lock(blocker);
list_add_tail(&waiter->c.flc_blocked_member, list_add_tail(&waiter->flc_blocked_member,
&blocker->c.flc_blocked_requests); &blocker->flc_blocked_requests);
if ((blocker->c.flc_flags & (FL_POSIX|FL_OFDLCK)) == FL_POSIX)
locks_insert_global_blocked(&waiter->c);
/* The requests in waiter->fl_blocked are known to conflict with if ((blocker->flc_flags & (FL_POSIX|FL_OFDLCK)) == (FL_POSIX|FL_OFDLCK))
locks_insert_global_blocked(waiter);
/* The requests in waiter->flc_blocked are known to conflict with
* waiter, but might not conflict with blocker, or the requests * waiter, but might not conflict with blocker, or the requests
* and lock which block it. So they all need to be woken. * 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. */ /* Must be called with flc_lock held. */
static void locks_insert_block(struct file_lock *blocker, static void locks_insert_block(struct file_lock *blocker,
struct file_lock *waiter, struct file_lock *waiter,
bool conflict(struct file_lock *, bool conflict(struct file_lock_core *,
struct file_lock *)) struct file_lock_core *))
{ {
spin_lock(&blocked_lock_lock); spin_lock(&blocked_lock_lock);
__locks_insert_block(blocker, waiter, conflict); __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 /* Determine if lock sys_fl blocks lock caller_fl. Common functionality
* checks for shared/exclusive status of overlapping locks. * checks for shared/exclusive status of overlapping locks.
*/ */
static bool locks_conflict(struct file_lock *caller_fl, static bool locks_conflict(struct file_lock_core *caller_flc,
struct file_lock *sys_fl) struct file_lock_core *sys_flc)
{ {
if (lock_is_write(sys_fl)) if (sys_flc->flc_type == F_WRLCK)
return true; return true;
if (lock_is_write(caller_fl)) if (caller_flc->flc_type == F_WRLCK)
return true; return true;
return false; 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 /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
* checking before calling the locks_conflict(). * checking before calling the locks_conflict().
*/ */
static bool posix_locks_conflict(struct file_lock *caller_fl, static bool posix_locks_conflict(struct file_lock_core *caller_flc,
struct file_lock *sys_fl) 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 /* POSIX locks owned by the same process do not conflict with
* each other. * each other.
*/ */
if (posix_same_owner(&caller_fl->c, &sys_fl->c)) if (posix_same_owner(caller_flc, sys_flc))
return false; return false;
/* Check whether they overlap */ /* Check whether they overlap */
if (!locks_overlap(caller_fl, sys_fl)) if (!locks_overlap(caller_fl, sys_fl))
return false; 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 /* 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, static bool posix_test_locks_conflict(struct file_lock *caller_fl,
struct file_lock *sys_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. */ /* F_UNLCK checks any locks on the same fd. */
if (lock_is_unlock(caller_fl)) { 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 false;
return locks_overlap(caller_fl, sys_fl); 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 /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
* checking before calling the locks_conflict(). * checking before calling the locks_conflict().
*/ */
static bool flock_locks_conflict(struct file_lock *caller_fl, static bool flock_locks_conflict(struct file_lock_core *caller_flc,
struct file_lock *sys_fl) struct file_lock_core *sys_flc)
{ {
/* FLOCK locks referring to the same filp do not conflict with /* FLOCK locks referring to the same filp do not conflict with
* each other. * 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 false;
return locks_conflict(caller_fl, sys_fl); return locks_conflict(caller_flc, sys_flc);
} }
void void
@ -980,25 +988,27 @@ EXPORT_SYMBOL(posix_test_lock);
#define MAX_DEADLK_ITERATIONS 10 #define MAX_DEADLK_ITERATIONS 10
/* Find a lock that the owner of the given block_fl is blocking on. */ /* Find a lock that the owner of the given @blocker is blocking on. */
static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) 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)) { hash_for_each_possible(blocked_hash, flc, flc_link, posix_owner_key(blocker)) {
if (posix_same_owner(&fl->c, &block_fl->c)) { if (posix_same_owner(flc, blocker)) {
while (fl->c.flc_blocker) while (flc->flc_blocker)
fl = fl->c.flc_blocker; flc = &flc->flc_blocker->c;
return fl; return flc;
} }
} }
return NULL; return NULL;
} }
/* Must be called with the blocked_lock_lock held! */ /* 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 *block_fl)
{ {
struct file_lock_core *caller = &caller_fl->c;
struct file_lock_core *blocker = &block_fl->c;
int i = 0; int i = 0;
lockdep_assert_held(&blocked_lock_lock); 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 * This deadlock detector can't reasonably detect deadlocks with
* FL_OFDLCK locks, since they aren't owned by a process, per-se. * FL_OFDLCK locks, since they aren't owned by a process, per-se.
*/ */
if (caller_fl->c.flc_flags & FL_OFDLCK) if (caller->flc_flags & FL_OFDLCK)
return 0; 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) if (i++ > MAX_DEADLK_ITERATIONS)
return 0; return false;
if (posix_same_owner(&caller_fl->c, &block_fl->c)) if (posix_same_owner(caller, blocker))
return 1; return true;
} }
return 0; return false;
} }
/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks /* 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: find_conflict:
list_for_each_entry(fl, &ctx->flc_flock, c.flc_list) { 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; continue;
error = -EAGAIN; error = -EAGAIN;
if (!(request->c.flc_flags & FL_SLEEP)) 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) { if (request->c.flc_type != F_UNLCK) {
list_for_each_entry(fl, &ctx->flc_posix, c.flc_list) { 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; continue;
if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable
&& (*fl->fl_lmops->lm_lock_expirable)(fl)) { && (*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; bool rc;
struct file_lock *lease = file_lock(lc);
struct file_lock *breaker = file_lock(bc);
if (lease->fl_lmops->lm_breaker_owns_lease if (lease->fl_lmops->lm_breaker_owns_lease
&& lease->fl_lmops->lm_breaker_owns_lease(lease)) && lease->fl_lmops->lm_breaker_owns_lease(lease))
return false; 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; rc = false;
goto trace; 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; rc = false;
goto trace; goto trace;
} }
rc = locks_conflict(breaker, lease); rc = locks_conflict(bc, lc);
trace: trace:
trace_leases_conflict(rc, lease, breaker); trace_leases_conflict(rc, lease, breaker);
return rc; return rc;
@ -1468,12 +1480,12 @@ static bool
any_leases_conflict(struct inode *inode, struct file_lock *breaker) any_leases_conflict(struct inode *inode, struct file_lock *breaker)
{ {
struct file_lock_context *ctx = inode->i_flctx; struct file_lock_context *ctx = inode->i_flctx;
struct file_lock *fl; struct file_lock_core *flc;
lockdep_assert_held(&ctx->flc_lock); lockdep_assert_held(&ctx->flc_lock);
list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) { list_for_each_entry(flc, &ctx->flc_lease, flc_list) {
if (leases_conflict(fl, breaker)) if (leases_conflict(flc, &breaker->c))
return true; return true;
} }
return false; 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) { 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; continue;
if (want_write) { if (want_write) {
if (fl->c.flc_flags & FL_UNLOCK_PENDING) if (fl->c.flc_flags & FL_UNLOCK_PENDING)