From 778fc546f749c588aa2f6cd50215d2715c374252 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 26 Jul 2011 18:25:49 -0400 Subject: locks: fix tracking of inprogress lease breaks We currently use a bit in fl_flags to record whether a lease is being broken, and set fl_type to the type (RDLCK or UNLCK) that it will eventually have. This means that once the lease break starts, we forget what the lease's type *used* to be. Breaking a read lease will then result in blocking read opens, even though there's no conflict--because the lease type is now F_UNLCK and we can no longer tell whether it was previously a read or write lease. So, instead keep fl_type as the original type (the type which we enforce), and keep track of whether we're unlocking or merely downgrading by replacing the single FL_INPROGRESS flag by FL_UNLOCK_PENDING and FL_DOWNGRADE_PENDING flags. To get this right we also need to track separate downgrade and break times, to handle the case where a write-leased file gets conflicting opens first for read, then later for write. (I first considered just eliminating the downgrade behavior completely--nfsv4 doesn't need it, and nobody as far as I can tell actually uses it currently--but Jeremy Allison tells me that Windows oplocks do behave this way, so Samba will probably use this some day.) Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields --- include/linux/fs.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 327fdd4de85f..76460edf1648 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1065,7 +1065,8 @@ static inline int file_check_writeable(struct file *filp) #define FL_LEASE 32 /* lease held on this file */ #define FL_CLOSE 64 /* unlock on close */ #define FL_SLEEP 128 /* A blocking lock */ -#define FL_INPROGRESS 256 /* Lease is being broken */ +#define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */ +#define FL_UNLOCK_PENDING 512 /* Lease is being broken */ /* * Special return value from posix_lock_file() and vfs_lock_file() for @@ -1122,7 +1123,9 @@ struct file_lock { loff_t fl_end; struct fasync_struct * fl_fasync; /* for lease break notifications */ - unsigned long fl_break_time; /* for nonblocking lease breaks */ + /* for lease breaks: */ + unsigned long fl_break_time; + unsigned long fl_downgrade_time; const struct file_lock_operations *fl_ops; /* Callbacks for filesystems */ const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */ -- cgit v1.2.2