linux-and-locks-cleanup-20070202

fix linux flock, remove a bogus lock assert, and fix pid tracking to avoid useless panic

acinclude.m4

@@ -606,6 +606,7 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*)
 	  	 LINUX_IOP_I_PERMISSION_TAKES_NAMEIDATA
 	  	 LINUX_DOP_D_REVALIDATE_TAKES_NAMEIDATA
 	  	 LINUX_AOP_WRITEBACK_CONTROL
+		 LINUX_FS_STRUCT_FOP_HAS_FLOCK
 		 LINUX_KERNEL_LINUX_SYSCALL_H
 		 LINUX_KERNEL_LINUX_SEQ_FILE_H
 		 LINUX_KERNEL_SELINUX
@@ -830,6 +831,9 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*)
 		 if test "x$ac_cv_linux_init_work_has_data" = "xyes" ; then
 		  AC_DEFINE(INIT_WORK_HAS_DATA, 1, [define if INIT_WORK takes a data (3rd) argument])
 		 fi
+		 if test "x$ac_cv_linux_fs_struct_fop_has_flock" = "xyes" ; then
+		  AC_DEFINE(STRUCT_FILE_OPERATIONS_HAS_FLOCK, 1, [define if your struct file_operations has flock])
+		 fi
                 :
 		fi
 esac

src/afs/LINUX/osi_vnodeops.c

@@ -490,7 +490,8 @@ afs_linux_lock(struct file *fp, int cmd, struct file_lock *flp)
     AFS_GUNLOCK();
 
 #ifdef AFS_LINUX24_ENV
-    if (code == 0 && (cmd == F_SETLK || cmd == F_SETLKW)) {
+    if ((code == 0 || flp->fl_type == F_UNLCK) && 
+        (cmd == F_SETLK || cmd == F_SETLKW)) {
 #ifdef AFS_LINUX26_ENV
        struct file_lock flp2;
        flp2 = *flp;
@@ -499,8 +500,7 @@ afs_linux_lock(struct file *fp, int cmd, struct file_lock *flp)
 #else
        code = posix_lock_file(fp, flp, 0);
 #endif 
-       osi_Assert(code != -EAGAIN); /* there should be no conflicts */
-       if (code) {
+       if (code && flp->fl_type != F_UNLCK) {
            struct AFS_FLOCK flock2;
            flock2 = flock;
            flock2.l_type = F_UNLCK;
@@ -521,6 +521,59 @@ afs_linux_lock(struct file *fp, int cmd, struct file_lock *flp)
 
 }
 
+#ifdef STRUCT_FILE_OPERATIONS_HAS_FLOCK
+static int
+afs_linux_flock(struct file *fp, int cmd, struct file_lock *flp) {
+    int code = 0;
+    struct vcache *vcp = VTOAFS(FILE_INODE(fp));
+    cred_t *credp = crref();
+    struct AFS_FLOCK flock;
+    /* Convert to a lock format afs_lockctl understands. */
+    memset((char *)&flock, 0, sizeof(flock));
+    flock.l_type = flp->fl_type;
+    flock.l_pid = flp->fl_pid;
+    flock.l_whence = 0;
+    flock.l_start = 0;
+    flock.l_len = OFFSET_MAX;
+
+    /* Safe because there are no large files, yet */
+#if defined(F_GETLK64) && (F_GETLK != F_GETLK64)
+    if (cmd == F_GETLK64)
+	cmd = F_GETLK;
+    else if (cmd == F_SETLK64)
+	cmd = F_SETLK;
+    else if (cmd == F_SETLKW64)
+	cmd = F_SETLKW;
+#endif /* F_GETLK64 && F_GETLK != F_GETLK64 */
+
+    AFS_GLOCK();
+    code = afs_lockctl(vcp, &flock, cmd, credp);
+    AFS_GUNLOCK();
+
+    if ((code == 0 || flp->fl_type == F_UNLCK) && 
+        (cmd == F_SETLK || cmd == F_SETLKW)) {
+       struct file_lock flp2;
+       flp2 = *flp;
+       flp2.fl_flags &=~ FL_SLEEP;
+       code = flock_lock_file_wait(fp, &flp2);
+       if (code && flp->fl_type != F_UNLCK) {
+           struct AFS_FLOCK flock2;
+           flock2 = flock;
+           flock2.l_type = F_UNLCK;
+           AFS_GLOCK();
+           afs_lockctl(vcp, &flock2, F_SETLK, credp);
+           AFS_GUNLOCK();
+       }
+    }
+    /* Convert flock back to Linux's file_lock */
+    flp->fl_type = flock.l_type;
+    flp->fl_pid = flock.l_pid;
+
+    crfree(credp);
+    return -code;
+}
+#endif
+
 /* afs_linux_flush
  * essentially the same as afs_fsync() but we need to get the return
  * code for the sys_close() here, not afs_linux_release(), so call
@@ -612,6 +665,9 @@ struct file_operations afs_file_fops = {
   .release =	afs_linux_release,
   .fsync =	afs_linux_fsync,
   .lock =	afs_linux_lock,
+#ifdef STRUCT_FILE_OPERATIONS_HAS_FLOCK
+  .flock =	afs_linux_flock,
+#endif
 };
 
 

src/afs/afs_callback.c

@@ -136,8 +136,8 @@ SRXAFSCB_GetCE(struct rx_call *a_call, afs_int32 a_index,
     a_result->lock.readersReading = tvc->lock.readers_reading;
     a_result->lock.numWaiting = tvc->lock.num_waiting;
 #if defined(INSTRUMENT_LOCKS)
-    a_result->lock.pid_last_reader = tvc->lock.pid_last_reader;
-    a_result->lock.pid_writer = tvc->lock.pid_writer;
+    a_result->lock.pid_last_reader = MyPidxx2Pid(tvc->lock.pid_last_reader);
+    a_result->lock.pid_writer = MyPidxx2Pid(tvc->lock.pid_writer);
     a_result->lock.src_indicator = tvc->lock.src_indicator;
 #else
     /* On osf20 , the vcache does not maintain these three fields */
@@ -222,8 +222,8 @@ SRXAFSCB_GetCE64(struct rx_call *a_call, afs_int32 a_index,
     a_result->lock.readersReading = tvc->lock.readers_reading;
     a_result->lock.numWaiting = tvc->lock.num_waiting;
 #if defined(INSTRUMENT_LOCKS)
-    a_result->lock.pid_last_reader = tvc->lock.pid_last_reader;
-    a_result->lock.pid_writer = tvc->lock.pid_writer;
+    a_result->lock.pid_last_reader = MyPidxx2Pid(tvc->lock.pid_last_reader);
+    a_result->lock.pid_writer = MyPidxx2Pid(tvc->lock.pid_writer);
     a_result->lock.src_indicator = tvc->lock.src_indicator;
 #else
     /* On osf20 , the vcache does not maintain these three fields */

src/afs/lock.h

@@ -89,7 +89,7 @@ typedef struct afs_bozoLock afs_bozoLock_t;
 #if defined(AFS_SUN57_ENV)
 typedef kthread_t * afs_lock_tracker_t;
 #define MyPidxx (curthread)
-#define MyPidxx2Pid(x) (ttoproc(x)->p_pid)
+#define MyPidxx2Pid(x) (x ? ttoproc(x)->p_pid : 0)
 #elif defined(AFS_SUN5_ENV) || defined(AFS_OBSD_ENV)
 typedef unsigned int afs_lock_tracker_t;
 #define MyPidxx (curproc->p_pid)
@@ -104,7 +104,7 @@ extern tid_t thread_self();
 #if defined(AFS_HPUX101_ENV)
 typedef struct proc * afs_lock_tracker_t;
 #define MyPidxx (u.u_procp)
-#define MyPidxx2Pid(x) ((afs_int32)p_pid(x))
+#define MyPidxx2Pid(x) (x ? (afs_int32)p_pid(x) : 0)
 #else
 #if defined(AFS_SGI64_ENV)
 #if defined(AFS_SGI65_ENV)
@@ -120,7 +120,7 @@ typedef unsigned int afs_lock_tracker_t;
 #ifdef AFS_LINUX20_ENV
 typedef struct task_struct * afs_lock_tracker_t;
 #define MyPidxx (current)
-#define MyPidxx2Pid(x) ((x)->pid)
+#define MyPidxx2Pid(x) (x? (x)->pid : 0)
 #else
 #if defined(AFS_DARWIN_ENV)
 #if defined(AFS_DARWIN80_ENV)

src/cf/linux-test4.m4

@@ -761,3 +761,14 @@ INIT_WORK(w,f,i);],
       ac_cv_linux_init_work_has_data=no)])
   AC_MSG_RESULT($ac_cv_linux_init_work_has_data)])
 
+
+AC_DEFUN([LINUX_FS_STRUCT_FOP_HAS_FLOCK], [
+  AC_MSG_CHECKING([for flock in struct file_operations])
+  AC_CACHE_VAL([ac_cv_linux_fs_struct_fop_has_flock], [
+    AC_TRY_KBUILD(
+[#include <linux/fs.h>],
+[struct file_operations _fop;
+_fop.flock(NULL, 0, NULL);],
+      ac_cv_linux_fs_struct_fop_has_flock=yes,
+      ac_cv_linux_fs_struct_fop_has_flock=no)])
+  AC_MSG_RESULT($ac_cv_linux_fs_struct_fop_has_flock)])