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authorMarc Eshel <eshel@almaden.ibm.com>2006-12-05 23:31:28 -0500
committerJ. Bruce Fields <bfields@citi.umich.edu>2007-05-06 20:38:49 -0400
commit2beb6614f5e36c6165b704c167d82ef3e4ceaa0c (patch)
tree7c5c1277f139c754d7b73a1822016574de655bd6 /include/linux/fs.h
parentfd85b8170dabbf021987875ef7f903791f4f181e (diff)
locks: add fl_grant callback for asynchronous lock return
Acquiring a lock on a cluster filesystem may require communication with remote hosts, and to avoid blocking lockd or nfsd threads during such communication, we allow the results to be returned asynchronously. When a ->lock() call needs to block, the file system will return -EINPROGRESS, and then later return the results with a call to the routine in the fl_grant field of the lock_manager_operations struct. This differs from the case when ->lock returns -EAGAIN to a blocking lock request; in that case, the filesystem calls fl_notify when the lock is granted, and the caller retries the original lock. So while fl_notify is merely a hint to the caller that it should retry, fl_grant actually communicates the final result of the lock operation (with the lock already acquired in the succesful case). Therefore fl_grant takes a lock, a status and, for the test lock case, a conflicting lock. We also allow fl_grant to return an error to the filesystem, to handle the case where the fl_grant requests arrives after the lock manager has already given up waiting for it. Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 64b8ae20530..b22991d5f16 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -785,6 +785,7 @@ struct file_lock_operations {
struct lock_manager_operations {
int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
void (*fl_notify)(struct file_lock *); /* unblock callback */
+ int (*fl_grant)(struct file_lock *, struct file_lock *, int);
void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
void (*fl_release_private)(struct file_lock *);
void (*fl_break)(struct file_lock *);