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locks: prevent ENOMEM on lease unlock 

Removing a lock shouldn't require any allocations; a failure due to
ENOMEM leaves the caller with a choice between retrying or giving up and
leaking an unused lease.

Next we should split the other lease calls into add and delete cases.
I wanted to start with just the bugfix.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
J. Bruce Fields 2010-10-30 17:31:13 -04:00 committed by Linus Torvalds
parent 0d07025eff
commit 0ceaf6c700
1 changed files with 30 additions and 13 deletions
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43
fs/locks.c
View File

@ -1441,7 +1441,8 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
return 0;
out:
locks_free_lock(lease);
if (arg != F_UNLCK)
locks_free_lock(lease);
return error;
}
EXPORT_SYMBOL(generic_setlease);
@ -1493,17 +1494,16 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
}
EXPORT_SYMBOL_GPL(vfs_setlease);
/**
* fcntl_setlease - sets a lease on an open file
* @fd: open file descriptor
* @filp: file pointer
* @arg: type of lease to obtain
*
* Call this fcntl to establish a lease on the file.
* Note that you also need to call %F_SETSIG to
* receive a signal when the lease is broken.
*/
int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
static int do_fcntl_delete_lease(struct file *filp)
{
struct file_lock fl, *flp = &fl;
lease_init(filp, F_UNLCK, flp);
return vfs_setlease(filp, F_UNLCK, &flp);
}
static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
{
struct file_lock *fl;
struct fasync_struct *new;
@ -1521,7 +1521,7 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
}
lock_flocks();
error = __vfs_setlease(filp, arg, &fl);
if (error || arg == F_UNLCK)
if (error)
goto out_unlock;
/*
@ -1549,6 +1549,23 @@ out_unlock:
return error;
}
/**
* fcntl_setlease - sets a lease on an open file
* @fd: open file descriptor
* @filp: file pointer
* @arg: type of lease to obtain
*
* Call this fcntl to establish a lease on the file.
* Note that you also need to call %F_SETSIG to
* receive a signal when the lease is broken.
*/
int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
{
if (arg == F_UNLCK)
return do_fcntl_delete_lease(filp);
return do_fcntl_add_lease(fd, filp, arg);
}
/**
* flock_lock_file_wait - Apply a FLOCK-style lock to a file
* @filp: The file to apply the lock to