1 files changed, 77 insertions, 50 deletions

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 3ce026d..6586a0c 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -146,6 +146,9 @@ typedef struct BDRVRawState {
     bool has_discard:1;
     bool has_write_zeroes:1;
     bool discard_zeroes:1;
+#ifdef CONFIG_FIEMAP
+    bool skip_fiemap;
+#endif
 } BDRVRawState;
 
 typedef struct BDRVRawReopenState {
@@ -1272,53 +1275,29 @@ static int raw_create(const char *filename, QEMUOptionParameter *options,
     return result;
 }
 
-/*
- * Returns true iff the specified sector is present in the disk image. Drivers
- * not implementing the functionality are assumed to not support backing files,
- * hence all their sectors are reported as allocated.
- *
- * If 'sector_num' is beyond the end of the disk image the return value is 0
- * and 'pnum' is set to 0.
- *
- * 'pnum' is set to the number of sectors (including and immediately following
- * the specified sector) that are known to be in the same
- * allocated/unallocated state.
- *
- * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
- * beyond the end of the disk image it will be clamped.
- */
-static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
-                                            int64_t sector_num,
-                                            int nb_sectors, int *pnum)
+static int64_t try_fiemap(BlockDriverState *bs, off_t start, off_t *data,
+                          off_t *hole, int nb_sectors, int *pnum)
 {
-    off_t start, data, hole;
-    int64_t ret;
-
-    ret = fd_open(bs);
-    if (ret < 0) {
-        return ret;
-    }
-
-    start = sector_num * BDRV_SECTOR_SIZE;
-    ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
-
 #ifdef CONFIG_FIEMAP
-
     BDRVRawState *s = bs->opaque;
+    int64_t ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
     struct {
         struct fiemap fm;
         struct fiemap_extent fe;
     } f;
 
+    if (s->skip_fiemap) {
+        return -ENOTSUP;
+    }
+
     f.fm.fm_start = start;
     f.fm.fm_length = (int64_t)nb_sectors * BDRV_SECTOR_SIZE;
     f.fm.fm_flags = 0;
     f.fm.fm_extent_count = 1;
     f.fm.fm_reserved = 0;
     if (ioctl(s->fd, FS_IOC_FIEMAP, &f) == -1) {
-        /* Assume everything is allocated.  */
-        *pnum = nb_sectors;
-        return ret;
+        s->skip_fiemap = true;
+        return -errno;
     }
 
     if (f.fm.fm_mapped_extents == 0) {
@@ -1326,44 +1305,92 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
          * f.fm.fm_start + f.fm.fm_length must be clamped to the file size!
          */
         off_t length = lseek(s->fd, 0, SEEK_END);
-        hole = f.fm.fm_start;
-        data = MIN(f.fm.fm_start + f.fm.fm_length, length);
+        *hole = f.fm.fm_start;
+        *data = MIN(f.fm.fm_start + f.fm.fm_length, length);
     } else {
-        data = f.fe.fe_logical;
-        hole = f.fe.fe_logical + f.fe.fe_length;
+        *data = f.fe.fe_logical;
+        *hole = f.fe.fe_logical + f.fe.fe_length;
         if (f.fe.fe_flags & FIEMAP_EXTENT_UNWRITTEN) {
             ret |= BDRV_BLOCK_ZERO;
         }
     }
 
-#elif defined SEEK_HOLE && defined SEEK_DATA
+    return ret;
+#else
+    return -ENOTSUP;
+#endif
+}
 
+static int64_t try_seek_hole(BlockDriverState *bs, off_t start, off_t *data,
+                             off_t *hole, int *pnum)
+{
+#if defined SEEK_HOLE && defined SEEK_DATA
     BDRVRawState *s = bs->opaque;
 
-    hole = lseek(s->fd, start, SEEK_HOLE);
-    if (hole == -1) {
+    *hole = lseek(s->fd, start, SEEK_HOLE);
+    if (*hole == -1) {
         /* -ENXIO indicates that sector_num was past the end of the file.
          * There is a virtual hole there.  */
         assert(errno != -ENXIO);
 
-        /* Most likely EINVAL.  Assume everything is allocated.  */
-        *pnum = nb_sectors;
-        return ret;
+        return -errno;
     }
 
-    if (hole > start) {
-        data = start;
+    if (*hole > start) {
+        *data = start;
     } else {
         /* On a hole.  We need another syscall to find its end.  */
-        data = lseek(s->fd, start, SEEK_DATA);
-        if (data == -1) {
-            data = lseek(s->fd, 0, SEEK_END);
+        *data = lseek(s->fd, start, SEEK_DATA);
+        if (*data == -1) {
+            *data = lseek(s->fd, 0, SEEK_END);
         }
     }
+
+    return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
 #else
-    data = 0;
-    hole = start + nb_sectors * BDRV_SECTOR_SIZE;
+    return -ENOTSUP;
 #endif
+}
+
+/*
+ * Returns true iff the specified sector is present in the disk image. Drivers
+ * not implementing the functionality are assumed to not support backing files,
+ * hence all their sectors are reported as allocated.
+ *
+ * If 'sector_num' is beyond the end of the disk image the return value is 0
+ * and 'pnum' is set to 0.
+ *
+ * 'pnum' is set to the number of sectors (including and immediately following
+ * the specified sector) that are known to be in the same
+ * allocated/unallocated state.
+ *
+ * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
+ * beyond the end of the disk image it will be clamped.
+ */
+static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
+                                                    int64_t sector_num,
+                                                    int nb_sectors, int *pnum)
+{
+    off_t start, data = 0, hole = 0;
+    int64_t ret;
+
+    ret = fd_open(bs);
+    if (ret < 0) {
+        return ret;
+    }
+
+    start = sector_num * BDRV_SECTOR_SIZE;
+
+    ret = try_fiemap(bs, start, &data, &hole, nb_sectors, pnum);
+    if (ret < 0) {
+        ret = try_seek_hole(bs, start, &data, &hole, pnum);
+        if (ret < 0) {
+            /* Assume everything is allocated. */
+            data = 0;
+            hole = start + nb_sectors * BDRV_SECTOR_SIZE;
+            ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
+        }
+    }
 
     if (data <= start) {
         /* On a data extent, compute sectors to the end of the extent.  */