From c5b1f0d92c36851aca09ac6c7c0c4f9690ac14f3 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 27 Oct 2010 15:46:08 +0200 Subject: locks/nfsd: allocate file lock outside of spinlock As suggested by Christoph Hellwig, this moves allocation of new file locks out of generic_setlease into the callers, nfs4_open_delegation and fcntl_setlease in order to allow GFP_KERNEL allocations when lock_flocks has become a spinlock. Signed-off-by: Arnd Bergmann Acked-by: J. Bruce Fields --- fs/locks.c | 36 ++++++++++++------------------------ 1 file changed, 12 insertions(+), 24 deletions(-) (limited to 'fs/locks.c') diff --git a/fs/locks.c b/fs/locks.c index 8b2b6ad56a09..0391d2ff5a4e 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -162,10 +162,11 @@ EXPORT_SYMBOL_GPL(unlock_flocks); static struct kmem_cache *filelock_cache __read_mostly; /* Allocate an empty lock structure. */ -static struct file_lock *locks_alloc_lock(void) +struct file_lock *locks_alloc_lock(void) { return kmem_cache_alloc(filelock_cache, GFP_KERNEL); } +EXPORT_SYMBOL_GPL(locks_alloc_lock); void locks_release_private(struct file_lock *fl) { @@ -1365,7 +1366,6 @@ int fcntl_getlease(struct file *filp) int generic_setlease(struct file *filp, long arg, struct file_lock **flp) { struct file_lock *fl, **before, **my_before = NULL, *lease; - struct file_lock *new_fl = NULL; struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; int error, rdlease_count = 0, wrlease_count = 0; @@ -1385,11 +1385,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) lease = *flp; if (arg != F_UNLCK) { - error = -ENOMEM; - new_fl = locks_alloc_lock(); - if (new_fl == NULL) - goto out; - error = -EAGAIN; if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0)) goto out; @@ -1434,7 +1429,6 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) goto out; } - error = 0; if (arg == F_UNLCK) goto out; @@ -1442,15 +1436,11 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp) if (!leases_enable) goto out; - locks_copy_lock(new_fl, lease); - locks_insert_lock(before, new_fl); - - *flp = new_fl; + locks_insert_lock(before, lease); return 0; out: - if (new_fl != NULL) - locks_free_lock(new_fl); + locks_free_lock(lease); return error; } EXPORT_SYMBOL(generic_setlease); @@ -1514,26 +1504,24 @@ EXPORT_SYMBOL_GPL(vfs_setlease); */ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) { - struct file_lock fl, *flp = &fl; + struct file_lock *fl; struct inode *inode = filp->f_path.dentry->d_inode; int error; - locks_init_lock(&fl); - error = lease_init(filp, arg, &fl); - if (error) - return error; + fl = lease_alloc(filp, arg); + if (IS_ERR(fl)) + return PTR_ERR(fl); lock_flocks(); - - error = __vfs_setlease(filp, arg, &flp); + error = __vfs_setlease(filp, arg, &fl); if (error || arg == F_UNLCK) goto out_unlock; - error = fasync_helper(fd, filp, 1, &flp->fl_fasync); + error = fasync_helper(fd, filp, 1, &fl->fl_fasync); if (error < 0) { /* remove lease just inserted by setlease */ - flp->fl_type = F_UNLCK | F_INPROGRESS; - flp->fl_break_time = jiffies - 10; + fl->fl_type = F_UNLCK | F_INPROGRESS; + fl->fl_break_time = jiffies - 10; time_out_leases(inode); goto out_unlock; } -- cgit v1.2.3 From f7347ce4ee7c65415f84be915c018473e7076f31 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 27 Oct 2010 12:38:12 -0400 Subject: fasync: re-organize fasync entry insertion to allow it under a spinlock You currently cannot use "fasync_helper()" in an atomic environment to insert a new fasync entry, because it will need to allocate the new "struct fasync_struct". Yet fcntl_setlease() wants to call this under lock_flocks(), which is in the process of being converted from the BKL to a spinlock. In order to fix this, this abstracts out the actual fasync list insertion and the fasync allocations into functions of their own, and teaches fs/locks.c to pre-allocate the fasync_struct entry. That way the actual list insertion can happen while holding the required spinlock. Signed-off-by: Linus Torvalds [bfields@redhat.com: rebase on top of my changes to Arnd's patch] Tested-by: J. Bruce Fields Signed-off-by: Arnd Bergmann --- fs/locks.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'fs/locks.c') diff --git a/fs/locks.c b/fs/locks.c index 0391d2ff5a4e..85fd9ce1abae 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1505,6 +1505,7 @@ EXPORT_SYMBOL_GPL(vfs_setlease); int fcntl_setlease(unsigned int fd, struct file *filp, long arg) { struct file_lock *fl; + struct fasync_struct *new; struct inode *inode = filp->f_path.dentry->d_inode; int error; @@ -1512,12 +1513,25 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) if (IS_ERR(fl)) return PTR_ERR(fl); + new = fasync_alloc(); + if (!new) { + locks_free_lock(fl); + return -ENOMEM; + } lock_flocks(); error = __vfs_setlease(filp, arg, &fl); if (error || arg == F_UNLCK) goto out_unlock; - error = fasync_helper(fd, filp, 1, &fl->fl_fasync); + /* + * fasync_insert_entry() returns the old entry if any. + * If there was no old entry, then it used 'new' and + * inserted it into the fasync list. Clear new so that + * we don't release it here. + */ + if (!fasync_insert_entry(fd, filp, &fl->fl_fasync, new)) + new = NULL; + if (error < 0) { /* remove lease just inserted by setlease */ fl->fl_type = F_UNLCK | F_INPROGRESS; @@ -1529,6 +1543,8 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); out_unlock: unlock_flocks(); + if (new) + fasync_free(new); return error; } -- cgit v1.2.3 From 72f98e72551fad573c6cace8e8551ef094f482dd Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 27 Oct 2010 21:39:58 +0200 Subject: locks: turn lock_flocks into a spinlock Nothing depends on lock_flocks using the BKL any more, so we can do the switch over to a private spinlock. Signed-off-by: Arnd Bergmann --- fs/locks.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/locks.c') diff --git a/fs/locks.c b/fs/locks.c index 85fd9ce1abae..74c3df99c0e1 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -142,6 +142,7 @@ 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 @@ -149,13 +150,13 @@ static LIST_HEAD(blocked_list); */ void lock_flocks(void) { - lock_kernel(); + spin_lock(&file_lock_lock); } EXPORT_SYMBOL_GPL(lock_flocks); void unlock_flocks(void) { - unlock_kernel(); + spin_unlock(&file_lock_lock); } EXPORT_SYMBOL_GPL(unlock_flocks); -- cgit v1.2.3