Re: [PATCH v2 07/14] locks: convert to i_lock to protect i_flocklist
From: Jeff Layton
Date: Thu Jun 13 2013 - 11:10:25 EST
On Thu, 13 Jun 2013 10:41:40 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> On Tue, Jun 11, 2013 at 07:09:01AM -0400, Jeff Layton wrote:
> > Having a global lock that protects all of this code is a clear
> > scalability problem. Instead of doing that, move most of the code to be
> > protected by the i_lock instead.
> >
> > The exceptions are the global lists that file_lock->fl_link sits on.
> > Those still need a global lock of some sort, so wrap just those accesses
> > in the file_lock_lock().
> >
> > Note that this patch introduces a potential race in the deadlock
> > detection code which could result in either false positives or missed
> > file_lock loops. The blocked_list management needs to be done atomically
> > with the deadlock detection. This will be fixed in a later patch.
>
> Actually, the way I think I'd try this:
>
> 1. Introduce a new spinlock global_lock_lists_lock and take it
> in all the places we need a global lock.
> 2. Do the big flock_lock-to-i_lock conversion, deleting flock_lock
> in the process.
>
> Does that work?
>
> Yeah, more patch-ordering bike-shedding, but... I think that would be
> simple and bisectable and for a confusing long-untouched bit of code
> it's worth getting these little steps right if we can.
>
>
I don't know...that really sounds more like it'll just add to the
churn without making anything simpler. If we're concerned about
bisectability, I think it'd just be best to merge patches 7 and 8 and
call it a day...
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> > ---
> > Documentation/filesystems/Locking | 23 +++++--
> > fs/afs/flock.c | 5 +-
> > fs/ceph/locks.c | 2 +-
> > fs/ceph/mds_client.c | 8 +-
> > fs/cifs/cifsfs.c | 2 +-
> > fs/cifs/file.c | 13 ++--
> > fs/gfs2/file.c | 2 +-
> > fs/lockd/svcsubs.c | 12 ++--
> > fs/locks.c | 110 ++++++++++++++++++++-----------------
> > fs/nfs/delegation.c | 11 ++--
> > fs/nfs/nfs4state.c | 8 +-
> > fs/nfsd/nfs4state.c | 8 +-
> > include/linux/fs.h | 11 ----
> > 13 files changed, 113 insertions(+), 102 deletions(-)
> >
> > diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
> > index 0706d32..13f91ab 100644
> > --- a/Documentation/filesystems/Locking
> > +++ b/Documentation/filesystems/Locking
> > @@ -344,7 +344,7 @@ prototypes:
> >
> >
> > locking rules:
> > - file_lock_lock may block
> > + inode->i_lock may block
> > fl_copy_lock: yes no
> > fl_release_private: maybe no
> >
> > @@ -357,12 +357,21 @@ prototypes:
> > int (*lm_change)(struct file_lock **, int);
> >
> > locking rules:
> > - file_lock_lock may block
> > -lm_compare_owner: yes no
> > -lm_notify: yes no
> > -lm_grant: no no
> > -lm_break: yes no
> > -lm_change yes no
> > +
> > + inode->i_lock file_lock_lock may block
> > +lm_compare_owner: yes maybe no
> > +lm_notify: yes no no
> > +lm_grant: no no no
> > +lm_break: yes no no
> > +lm_change yes no no
> > +
> > + ->lm_compare_owner is generally called with *an* inode->i_lock
> > +held. It may not be the i_lock of the inode for either file_lock being
> > +compared! This is the case with deadlock detection, since the code has
> > +to chase down the owners of locks that may be entirely unrelated to the
> > +one on which the lock is being acquired. For deadlock detection however,
> > +the file_lock_lock is also held. The locks primarily ensure that neither
> > +file_lock disappear out from under you while doing the comparison.
> >
> > --------------------------- buffer_head -----------------------------------
> > prototypes:
> > diff --git a/fs/afs/flock.c b/fs/afs/flock.c
> > index 2497bf3..03fc0d1 100644
> > --- a/fs/afs/flock.c
> > +++ b/fs/afs/flock.c
> > @@ -252,6 +252,7 @@ static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key)
> > */
> > static int afs_do_setlk(struct file *file, struct file_lock *fl)
> > {
> > + struct inode = file_inode(file);
> > struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
> > afs_lock_type_t type;
> > struct key *key = file->private_data;
> > @@ -273,7 +274,7 @@ static int afs_do_setlk(struct file *file, struct file_lock *fl)
> >
> > type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> >
> > /* make sure we've got a callback on this file and that our view of the
> > * data version is up to date */
> > @@ -420,7 +421,7 @@ given_lock:
> > afs_vnode_fetch_status(vnode, NULL, key);
> >
> > error:
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > _leave(" = %d", ret);
> > return ret;
> >
> > diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> > index 202dd3d..cd0a664 100644
> > --- a/fs/ceph/locks.c
> > +++ b/fs/ceph/locks.c
> > @@ -194,7 +194,7 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
> > * Encode the flock and fcntl locks for the given inode into the pagelist.
> > * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
> > * sequential flock locks.
> > - * Must be called with lock_flocks() already held.
> > + * Must be called with inode->i_lock already held.
> > * If we encounter more of a specific lock type than expected,
> > * we return the value 1.
> > */
> > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > index 4f22671..ae621b5 100644
> > --- a/fs/ceph/mds_client.c
> > +++ b/fs/ceph/mds_client.c
> > @@ -2482,13 +2482,13 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
> >
> > ceph_pagelist_set_cursor(pagelist, &trunc_point);
> > do {
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > ceph_count_locks(inode, &num_fcntl_locks,
> > &num_flock_locks);
> > rec.v2.flock_len = (2*sizeof(u32) +
> > (num_fcntl_locks+num_flock_locks) *
> > sizeof(struct ceph_filelock));
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > /* pre-alloc pagelist */
> > ceph_pagelist_truncate(pagelist, &trunc_point);
> > @@ -2499,12 +2499,12 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
> >
> > /* encode locks */
> > if (!err) {
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > err = ceph_encode_locks(inode,
> > pagelist,
> > num_fcntl_locks,
> > num_flock_locks);
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > }
> > } while (err == -ENOSPC);
> > } else {
> > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> > index 3752b9f..e81655c 100644
> > --- a/fs/cifs/cifsfs.c
> > +++ b/fs/cifs/cifsfs.c
> > @@ -765,7 +765,7 @@ static loff_t cifs_llseek(struct file *file, loff_t offset, int whence)
> >
> > static int cifs_setlease(struct file *file, long arg, struct file_lock **lease)
> > {
> > - /* note that this is called by vfs setlease with lock_flocks held
> > + /* note that this is called by vfs setlease with i_lock held
> > to protect *lease from going away */
> > struct inode *inode = file_inode(file);
> > struct cifsFileInfo *cfile = file->private_data;
> > diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> > index 44a4f18..0dd10cd 100644
> > --- a/fs/cifs/file.c
> > +++ b/fs/cifs/file.c
> > @@ -1092,6 +1092,7 @@ struct lock_to_push {
> > static int
> > cifs_push_posix_locks(struct cifsFileInfo *cfile)
> > {
> > + struct inode *inode = cfile->dentry->d_inode;
> > struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
> > struct file_lock *flock, **before;
> > unsigned int count = 0, i = 0;
> > @@ -1102,12 +1103,12 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
> >
> > xid = get_xid();
> >
> > - lock_flocks();
> > - cifs_for_each_lock(cfile->dentry->d_inode, before) {
> > + spin_lock(&inode->i_lock);
> > + cifs_for_each_lock(inode, before) {
> > if ((*before)->fl_flags & FL_POSIX)
> > count++;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > INIT_LIST_HEAD(&locks_to_send);
> >
> > @@ -1126,8 +1127,8 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
> > }
> >
> > el = locks_to_send.next;
> > - lock_flocks();
> > - cifs_for_each_lock(cfile->dentry->d_inode, before) {
> > + spin_lock(&inode->i_lock);
> > + cifs_for_each_lock(inode, before) {
> > flock = *before;
> > if ((flock->fl_flags & FL_POSIX) == 0)
> > continue;
> > @@ -1152,7 +1153,7 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
> > lck->offset = flock->fl_start;
> > el = el->next;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
> > int stored_rc;
> > diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> > index acd1676..9e634e0 100644
> > --- a/fs/gfs2/file.c
> > +++ b/fs/gfs2/file.c
> > @@ -889,7 +889,7 @@ out_uninit:
> > * cluster; until we do, disable leases (by just returning -EINVAL),
> > * unless the administrator has requested purely local locking.
> > *
> > - * Locking: called under lock_flocks
> > + * Locking: called under i_lock
> > *
> > * Returns: errno
> > */
> > diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
> > index 97e8741..dc5c759 100644
> > --- a/fs/lockd/svcsubs.c
> > +++ b/fs/lockd/svcsubs.c
> > @@ -169,7 +169,7 @@ nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file,
> >
> > again:
> > file->f_locks = 0;
> > - lock_flocks(); /* protects i_flock list */
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl; fl = fl->fl_next) {
> > if (fl->fl_lmops != &nlmsvc_lock_operations)
> > continue;
> > @@ -181,7 +181,7 @@ again:
> > if (match(lockhost, host)) {
> > struct file_lock lock = *fl;
> >
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > lock.fl_type = F_UNLCK;
> > lock.fl_start = 0;
> > lock.fl_end = OFFSET_MAX;
> > @@ -193,7 +193,7 @@ again:
> > goto again;
> > }
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > return 0;
> > }
> > @@ -228,14 +228,14 @@ nlm_file_inuse(struct nlm_file *file)
> > if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares)
> > return 1;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl; fl = fl->fl_next) {
> > if (fl->fl_lmops == &nlmsvc_lock_operations) {
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return 1;
> > }
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > file->f_locks = 0;
> > return 0;
> > }
> > diff --git a/fs/locks.c b/fs/locks.c
> > index 3fd27f0..d7342a3 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -155,22 +155,9 @@ int lease_break_time = 45;
> >
> > static LIST_HEAD(file_lock_list);
> > static LIST_HEAD(blocked_list);
> > -static DEFINE_SPINLOCK(file_lock_lock);
> > -
> > -/*
> > - * Protects the two list heads above, plus the inode->i_flock list
> > - */
> > -void lock_flocks(void)
> > -{
> > - spin_lock(&file_lock_lock);
> > -}
> > -EXPORT_SYMBOL_GPL(lock_flocks);
> >
> > -void unlock_flocks(void)
> > -{
> > - spin_unlock(&file_lock_lock);
> > -}
> > -EXPORT_SYMBOL_GPL(unlock_flocks);
> > +/* Protects the two list heads above */
> > +static DEFINE_SPINLOCK(file_lock_lock);
> >
> > static struct kmem_cache *filelock_cache __read_mostly;
> >
> > @@ -488,25 +475,33 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
> > static inline void
> > locks_insert_global_blocked(struct file_lock *waiter)
> > {
> > + spin_lock(&file_lock_lock);
> > list_add(&waiter->fl_link, &blocked_list);
> > + spin_unlock(&file_lock_lock);
> > }
> >
> > static inline void
> > locks_delete_global_blocked(struct file_lock *waiter)
> > {
> > + spin_lock(&file_lock_lock);
> > list_del_init(&waiter->fl_link);
> > + spin_unlock(&file_lock_lock);
> > }
> >
> > static inline void
> > locks_insert_global_locks(struct file_lock *waiter)
> > {
> > + spin_lock(&file_lock_lock);
> > list_add_tail(&waiter->fl_link, &file_lock_list);
> > + spin_unlock(&file_lock_lock);
> > }
> >
> > static inline void
> > locks_delete_global_locks(struct file_lock *waiter)
> > {
> > + spin_lock(&file_lock_lock);
> > list_del_init(&waiter->fl_link);
> > + spin_unlock(&file_lock_lock);
> > }
> >
> > /* Remove waiter from blocker's block list.
> > @@ -523,9 +518,11 @@ static void __locks_delete_block(struct file_lock *waiter)
> > */
> > static void locks_delete_block(struct file_lock *waiter)
> > {
> > - lock_flocks();
> > + struct inode *inode = file_inode(waiter->fl_file);
> > +
> > + spin_lock(&inode->i_lock);
> > __locks_delete_block(waiter);
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > }
> >
> > /* Insert waiter into blocker's block list.
> > @@ -544,7 +541,7 @@ static void locks_insert_block(struct file_lock *blocker,
> > /*
> > * Wake up processes blocked waiting for blocker.
> > *
> > - * Must be called with the file_lock_lock held!
> > + * Must be called with the inode->i_lock of the blocker held!
> > */
> > static void locks_wake_up_blocks(struct file_lock *blocker)
> > {
> > @@ -649,8 +646,9 @@ void
> > posix_test_lock(struct file *filp, struct file_lock *fl)
> > {
> > struct file_lock *cfl;
> > + struct inode *inode = file_inode(filp);
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
> > if (!IS_POSIX(cfl))
> > continue;
> > @@ -663,7 +661,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
> > fl->fl_pid = pid_vnr(cfl->fl_nspid);
> > } else
> > fl->fl_type = F_UNLCK;
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return;
> > }
> > EXPORT_SYMBOL(posix_test_lock);
> > @@ -742,7 +740,7 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
> > return -ENOMEM;
> > }
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > if (request->fl_flags & FL_ACCESS)
> > goto find_conflict;
> >
> > @@ -772,9 +770,9 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
> > * give it the opportunity to lock the file.
> > */
> > if (found) {
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > cond_resched();
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > }
> >
> > find_conflict:
> > @@ -801,7 +799,7 @@ find_conflict:
> > error = 0;
> >
> > out:
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > if (new_fl)
> > locks_free_lock(new_fl);
> > return error;
> > @@ -831,7 +829,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
> > new_fl2 = locks_alloc_lock();
> > }
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > /*
> > * New lock request. Walk all POSIX locks and look for conflicts. If
> > * there are any, either return error or put the request on the
> > @@ -850,8 +848,14 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
> > if (!(request->fl_flags & FL_SLEEP))
> > goto out;
> > error = -EDEADLK;
> > + /*
> > + * XXX: potential race here. We should be adding the
> > + * file_lock to the global list before releasing lock.
> > + */
> > + spin_lock(&file_lock_lock);
> > if (posix_locks_deadlock(request, fl))
> > goto out;
> > + spin_unlock(&file_lock_lock);
> > error = FILE_LOCK_DEFERRED;
> > locks_insert_block(fl, request);
> > locks_insert_global_blocked(request);
> > @@ -1004,7 +1008,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
> > locks_wake_up_blocks(left);
> > }
> > out:
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > /*
> > * Free any unused locks.
> > */
> > @@ -1079,14 +1083,14 @@ int locks_mandatory_locked(struct inode *inode)
> > /*
> > * Search the lock list for this inode for any POSIX locks.
> > */
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
> > if (!IS_POSIX(fl))
> > continue;
> > if (fl->fl_owner != owner)
> > break;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return fl ? -EAGAIN : 0;
> > }
> >
> > @@ -1229,7 +1233,7 @@ int __break_lease(struct inode *inode, unsigned int mode)
> > if (IS_ERR(new_fl))
> > return PTR_ERR(new_fl);
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> >
> > time_out_leases(inode);
> >
> > @@ -1279,10 +1283,10 @@ restart:
> > break_time++;
> > }
> > locks_insert_block(flock, new_fl);
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > error = wait_event_interruptible_timeout(new_fl->fl_wait,
> > !new_fl->fl_next, break_time);
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > __locks_delete_block(new_fl);
> > if (error >= 0) {
> > if (error == 0)
> > @@ -1300,7 +1304,7 @@ restart:
> > }
> >
> > out:
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > locks_free_lock(new_fl);
> > return error;
> > }
> > @@ -1353,9 +1357,10 @@ EXPORT_SYMBOL(lease_get_mtime);
> > int fcntl_getlease(struct file *filp)
> > {
> > struct file_lock *fl;
> > + struct inode *inode = file_inode(filp);
> > int type = F_UNLCK;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > time_out_leases(file_inode(filp));
> > for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
> > fl = fl->fl_next) {
> > @@ -1364,7 +1369,7 @@ int fcntl_getlease(struct file *filp)
> > break;
> > }
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return type;
> > }
> >
> > @@ -1458,7 +1463,7 @@ static int generic_delete_lease(struct file *filp, struct file_lock **flp)
> > * The (input) flp->fl_lmops->lm_break function is required
> > * by break_lease().
> > *
> > - * Called with file_lock_lock held.
> > + * Called with inode->i_lock held.
> > */
> > int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
> > {
> > @@ -1527,11 +1532,12 @@ static int __vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
> >
> > int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
> > {
> > + struct inode *inode = file_inode(filp);
> > int error;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > error = __vfs_setlease(filp, arg, lease);
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > return error;
> > }
> > @@ -1549,6 +1555,7 @@ static int do_fcntl_delete_lease(struct file *filp)
> > static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
> > {
> > struct file_lock *fl, *ret;
> > + struct inode *inode = file_inode(filp);
> > struct fasync_struct *new;
> > int error;
> >
> > @@ -1562,10 +1569,10 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
> > return -ENOMEM;
> > }
> > ret = fl;
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > error = __vfs_setlease(filp, arg, &ret);
> > if (error) {
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > locks_free_lock(fl);
> > goto out_free_fasync;
> > }
> > @@ -1582,7 +1589,7 @@ static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
> > new = NULL;
> >
> > error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> >
> > out_free_fasync:
> > if (new)
> > @@ -2106,7 +2113,7 @@ void locks_remove_flock(struct file *filp)
> > fl.fl_ops->fl_release_private(&fl);
> > }
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > before = &inode->i_flock;
> >
> > while ((fl = *before) != NULL) {
> > @@ -2124,7 +2131,7 @@ void locks_remove_flock(struct file *filp)
> > }
> > before = &fl->fl_next;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > }
> >
> > /**
> > @@ -2137,14 +2144,15 @@ void locks_remove_flock(struct file *filp)
> > int
> > posix_unblock_lock(struct file *filp, struct file_lock *waiter)
> > {
> > + struct inode *inode = file_inode(filp);
> > int status = 0;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > if (waiter->fl_next)
> > __locks_delete_block(waiter);
> > else
> > status = -ENOENT;
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return status;
> > }
> >
> > @@ -2261,7 +2269,7 @@ static void *locks_start(struct seq_file *f, loff_t *pos)
> > {
> > loff_t *p = f->private;
> >
> > - lock_flocks();
> > + spin_lock(&file_lock_lock);
> > *p = (*pos + 1);
> > return seq_list_start(&file_lock_list, *pos);
> > }
> > @@ -2275,7 +2283,7 @@ static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
> >
> > static void locks_stop(struct seq_file *f, void *v)
> > {
> > - unlock_flocks();
> > + spin_unlock(&file_lock_lock);
> > }
> >
> > static const struct seq_operations locks_seq_operations = {
> > @@ -2322,7 +2330,8 @@ int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
> > {
> > struct file_lock *fl;
> > int result = 1;
> > - lock_flocks();
> > +
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
> > if (IS_POSIX(fl)) {
> > if (fl->fl_type == F_RDLCK)
> > @@ -2339,7 +2348,7 @@ int lock_may_read(struct inode *inode, loff_t start, unsigned long len)
> > result = 0;
> > break;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return result;
> > }
> >
> > @@ -2362,7 +2371,8 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
> > {
> > struct file_lock *fl;
> > int result = 1;
> > - lock_flocks();
> > +
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
> > if (IS_POSIX(fl)) {
> > if ((fl->fl_end < start) || (fl->fl_start > (start + len)))
> > @@ -2377,7 +2387,7 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
> > result = 0;
> > break;
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return result;
> > }
> >
> > diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
> > index 57db324..43ee7f9 100644
> > --- a/fs/nfs/delegation.c
> > +++ b/fs/nfs/delegation.c
> > @@ -73,20 +73,21 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_
> > if (inode->i_flock == NULL)
> > goto out;
> >
> > - /* Protect inode->i_flock using the file locks lock */
> > - lock_flocks();
> > + /* Protect inode->i_flock using the i_lock */
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
> > if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
> > continue;
> > if (nfs_file_open_context(fl->fl_file) != ctx)
> > continue;
> > - unlock_flocks();
> > + /* FIXME: safe to drop lock here while walking list? */
> > + spin_unlock(&inode->i_lock);
> > status = nfs4_lock_delegation_recall(fl, state, stateid);
> > if (status < 0)
> > goto out;
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > out:
> > return status;
> > }
> > diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> > index 1fab140..ff10b4a 100644
> > --- a/fs/nfs/nfs4state.c
> > +++ b/fs/nfs/nfs4state.c
> > @@ -1373,13 +1373,13 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
> > /* Guard against delegation returns and new lock/unlock calls */
> > down_write(&nfsi->rwsem);
> > /* Protect inode->i_flock using the BKL */
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
> > if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
> > continue;
> > if (nfs_file_open_context(fl->fl_file)->state != state)
> > continue;
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > status = ops->recover_lock(state, fl);
> > switch (status) {
> > case 0:
> > @@ -1406,9 +1406,9 @@ static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_
> > /* kill_proc(fl->fl_pid, SIGLOST, 1); */
> > status = 0;
> > }
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > }
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > out:
> > up_write(&nfsi->rwsem);
> > return status;
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 316ec84..f170518 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -2645,13 +2645,13 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
> >
> > list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru);
> >
> > - /* only place dl_time is set. protected by lock_flocks*/
> > + /* Only place dl_time is set; protected by i_lock: */
> > dp->dl_time = get_seconds();
> >
> > nfsd4_cb_recall(dp);
> > }
> >
> > -/* Called from break_lease() with lock_flocks() held. */
> > +/* Called from break_lease() with i_lock held. */
> > static void nfsd_break_deleg_cb(struct file_lock *fl)
> > {
> > struct nfs4_file *fp = (struct nfs4_file *)fl->fl_owner;
> > @@ -4520,7 +4520,7 @@ check_for_locks(struct nfs4_file *filp, struct nfs4_lockowner *lowner)
> > struct inode *inode = filp->fi_inode;
> > int status = 0;
> >
> > - lock_flocks();
> > + spin_lock(&inode->i_lock);
> > for (flpp = &inode->i_flock; *flpp != NULL; flpp = &(*flpp)->fl_next) {
> > if ((*flpp)->fl_owner == (fl_owner_t)lowner) {
> > status = 1;
> > @@ -4528,7 +4528,7 @@ check_for_locks(struct nfs4_file *filp, struct nfs4_lockowner *lowner)
> > }
> > }
> > out:
> > - unlock_flocks();
> > + spin_unlock(&inode->i_lock);
> > return status;
> > }
> >
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 94105d2..e2f896d 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -1024,8 +1024,6 @@ extern int vfs_setlease(struct file *, long, struct file_lock **);
> > extern int lease_modify(struct file_lock **, int);
> > extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
> > extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
> > -extern void lock_flocks(void);
> > -extern void unlock_flocks(void);
> > #else /* !CONFIG_FILE_LOCKING */
> > static inline int fcntl_getlk(struct file *file, struct flock __user *user)
> > {
> > @@ -1167,15 +1165,6 @@ static inline int lock_may_write(struct inode *inode, loff_t start,
> > {
> > return 1;
> > }
> > -
> > -static inline void lock_flocks(void)
> > -{
> > -}
> > -
> > -static inline void unlock_flocks(void)
> > -{
> > -}
> > -
> > #endif /* !CONFIG_FILE_LOCKING */
> >
> >
> > --
> > 1.7.1
> >
--
Jeff Layton <jlayton@xxxxxxxxxx>
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