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locks: allow {vfs,posix}_lock_file to return conflicting lock

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The nfsv4 protocol's lock operation, in the case of a conflict, returns
information about the conflicting lock.

It's unclear how clients can use this, so for now we're not going so far as to
add a filesystem method that can return a conflicting lock, but we may as well
return something in the local case when it's easy to.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
This commit is contained in:
Marc Eshel
2007-01-18 16:15:35 -05:00
committed by J. Bruce Fields
parent 7723ec9777
commit 150b393456
5 changed files with 32 additions and 36 deletions
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45
fs/locks.c
View File

@@ -801,7 +801,7 @@ out:
return error;
}
static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
{
struct file_lock *fl;
struct file_lock *new_fl = NULL;
@@ -1007,6 +1007,7 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
* posix_lock_file - Apply a POSIX-style lock to a file
* @filp: The file to apply the lock to
* @fl: The lock to be applied
* @conflock: Place to return a copy of the conflicting lock, if found.
*
* Add a POSIX style lock to a file.
* We merge adjacent & overlapping locks whenever possible.
@@ -1016,26 +1017,12 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
* whether or not a lock was successfully freed by testing the return
* value for -ENOENT.
*/
int posix_lock_file(struct file *filp, struct file_lock *fl)
{
return __posix_lock_file_conf(filp->f_path.dentry->d_inode, fl, NULL);
}
EXPORT_SYMBOL(posix_lock_file);
/**
* posix_lock_file_conf - Apply a POSIX-style lock to a file
* @filp: The file to apply the lock to
* @fl: The lock to be applied
* @conflock: Place to return a copy of the conflicting lock, if found.
*
* Except for the conflock parameter, acts just like posix_lock_file.
*/
int posix_lock_file_conf(struct file *filp, struct file_lock *fl,
int posix_lock_file(struct file *filp, struct file_lock *fl,
struct file_lock *conflock)
{
return __posix_lock_file_conf(filp->f_path.dentry->d_inode, fl, conflock);
return __posix_lock_file(filp->f_path.dentry->d_inode, fl, conflock);
}
EXPORT_SYMBOL(posix_lock_file_conf);
EXPORT_SYMBOL(posix_lock_file);
/**
* posix_lock_file_wait - Apply a POSIX-style lock to a file
@@ -1051,7 +1038,7 @@ int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
int error;
might_sleep ();
for (;;) {
error = posix_lock_file(filp, fl);
error = posix_lock_file(filp, fl, NULL);
if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP))
break;
error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
@@ -1123,7 +1110,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
fl.fl_end = offset + count - 1;
for (;;) {
error = __posix_lock_file_conf(inode, &fl, NULL);
error = __posix_lock_file(inode, &fl, NULL);
if (error != -EAGAIN)
break;
if (!(fl.fl_flags & FL_SLEEP))
@@ -1703,13 +1690,21 @@ out:
* @filp: The file to apply the lock to
* @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
* @fl: The lock to be applied
* @conf: Place to return a copy of the conflicting lock, if found.
*
* A caller that doesn't care about the conflicting lock may pass NULL
* as the final argument.
*
* If the filesystem defines a private ->lock() method, then @conf will
* be left unchanged; so a caller that cares should initialize it to
* some acceptable default.
*/
int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl)
int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
{
if (filp->f_op && filp->f_op->lock)
return filp->f_op->lock(filp, cmd, fl);
else
return posix_lock_file(filp, fl);
return posix_lock_file(filp, fl, conf);
}
EXPORT_SYMBOL_GPL(vfs_lock_file);
@@ -1776,7 +1771,7 @@ again:
goto out;
for (;;) {
error = vfs_lock_file(filp, cmd, file_lock);
error = vfs_lock_file(filp, cmd, file_lock, NULL);
if (error != -EAGAIN || cmd == F_SETLK)
break;
error = wait_event_interruptible(file_lock->fl_wait,
@@ -1902,7 +1897,7 @@ again:
goto out;
for (;;) {
error = vfs_lock_file(filp, cmd, file_lock);
error = vfs_lock_file(filp, cmd, file_lock, NULL);
if (error != -EAGAIN || cmd == F_SETLK64)
break;
error = wait_event_interruptible(file_lock->fl_wait,
@@ -1956,7 +1951,7 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
lock.fl_ops = NULL;
lock.fl_lmops = NULL;
vfs_lock_file(filp, F_SETLK, &lock);
vfs_lock_file(filp, F_SETLK, &lock, NULL);
if (lock.fl_ops && lock.fl_ops->fl_release_private)
lock.fl_ops->fl_release_private(&lock);