block/file-posix: Pass FD to locking helpers

raw_apply_lock_bytes() and raw_check_lock_bytes() currently take a
BDRVRawState *, but they only use the lock_fd field.  During image
creation, we do not have a BDRVRawState, but we do have an FD; so if we
want to reuse the functions there, we should modify them to receive only
the FD.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20180509215336.31304-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

block/file-posix.c

@@ -643,7 +643,7 @@ typedef enum {
  * file; if @unlock == true, also unlock the unneeded bytes.
  * @shared_perm_lock_bits is the mask of all permissions that are NOT shared.
  */
-static int raw_apply_lock_bytes(BDRVRawState *s,
+static int raw_apply_lock_bytes(int fd,
                                 uint64_t perm_lock_bits,
                                 uint64_t shared_perm_lock_bits,
                                 bool unlock, Error **errp)
@@ -654,13 +654,13 @@ static int raw_apply_lock_bytes(BDRVRawState *s,
     PERM_FOREACH(i) {
         int off = RAW_LOCK_PERM_BASE + i;
         if (perm_lock_bits & (1ULL << i)) {
-            ret = qemu_lock_fd(s->lock_fd, off, 1, false);
+            ret = qemu_lock_fd(fd, off, 1, false);
             if (ret) {
                 error_setg(errp, "Failed to lock byte %d", off);
                 return ret;
             }
         } else if (unlock) {
-            ret = qemu_unlock_fd(s->lock_fd, off, 1);
+            ret = qemu_unlock_fd(fd, off, 1);
             if (ret) {
                 error_setg(errp, "Failed to unlock byte %d", off);
                 return ret;
@@ -670,13 +670,13 @@ static int raw_apply_lock_bytes(BDRVRawState *s,
     PERM_FOREACH(i) {
         int off = RAW_LOCK_SHARED_BASE + i;
         if (shared_perm_lock_bits & (1ULL << i)) {
-            ret = qemu_lock_fd(s->lock_fd, off, 1, false);
+            ret = qemu_lock_fd(fd, off, 1, false);
             if (ret) {
                 error_setg(errp, "Failed to lock byte %d", off);
                 return ret;
             }
         } else if (unlock) {
-            ret = qemu_unlock_fd(s->lock_fd, off, 1);
+            ret = qemu_unlock_fd(fd, off, 1);
             if (ret) {
                 error_setg(errp, "Failed to unlock byte %d", off);
                 return ret;
@@ -687,8 +687,7 @@ static int raw_apply_lock_bytes(BDRVRawState *s,
 }
 
 /* Check "unshared" bytes implied by @perm and ~@shared_perm in the file. */
-static int raw_check_lock_bytes(BDRVRawState *s,
-                                uint64_t perm, uint64_t shared_perm,
+static int raw_check_lock_bytes(int fd, uint64_t perm, uint64_t shared_perm,
                                 Error **errp)
 {
     int ret;
@@ -698,7 +697,7 @@ static int raw_check_lock_bytes(BDRVRawState *s,
         int off = RAW_LOCK_SHARED_BASE + i;
         uint64_t p = 1ULL << i;
         if (perm & p) {
-            ret = qemu_lock_fd_test(s->lock_fd, off, 1, true);
+            ret = qemu_lock_fd_test(fd, off, 1, true);
             if (ret) {
                 char *perm_name = bdrv_perm_names(p);
                 error_setg(errp,
@@ -715,7 +714,7 @@ static int raw_check_lock_bytes(BDRVRawState *s,
         int off = RAW_LOCK_PERM_BASE + i;
         uint64_t p = 1ULL << i;
         if (!(shared_perm & p)) {
-            ret = qemu_lock_fd_test(s->lock_fd, off, 1, true);
+            ret = qemu_lock_fd_test(fd, off, 1, true);
             if (ret) {
                 char *perm_name = bdrv_perm_names(p);
                 error_setg(errp,
@@ -752,19 +751,20 @@ static int raw_handle_perm_lock(BlockDriverState *bs,
 
     switch (op) {
     case RAW_PL_PREPARE:
-        ret = raw_apply_lock_bytes(s, s->perm | new_perm,
+        ret = raw_apply_lock_bytes(s->lock_fd, s->perm | new_perm,
                                    ~s->shared_perm | ~new_shared,
                                    false, errp);
         if (!ret) {
-            ret = raw_check_lock_bytes(s, new_perm, new_shared, errp);
+            ret = raw_check_lock_bytes(s->lock_fd, new_perm, new_shared, errp);
             if (!ret) {
                 return 0;
             }
         }
         op = RAW_PL_ABORT;
         /* fall through to unlock bytes. */
     case RAW_PL_ABORT:
-        raw_apply_lock_bytes(s, s->perm, ~s->shared_perm, true, &local_err);
+        raw_apply_lock_bytes(s->lock_fd, s->perm, ~s->shared_perm,
+                             true, &local_err);
         if (local_err) {
             /* Theoretically the above call only unlocks bytes and it cannot
              * fail. Something weird happened, report it.
@@ -773,7 +773,8 @@ static int raw_handle_perm_lock(BlockDriverState *bs,
         }
         break;
     case RAW_PL_COMMIT:
-        raw_apply_lock_bytes(s, new_perm, ~new_shared, true, &local_err);
+        raw_apply_lock_bytes(s->lock_fd, new_perm, ~new_shared,
+                             true, &local_err);
         if (local_err) {
             /* Theoretically the above call only unlocks bytes and it cannot
              * fail. Something weird happened, report it.