btrfs: Rename found_type to extent_type in btrfs_get_extent

found_type really holds the type of extent and is guaranteed to to have
a value between [0, 2]. The only time it can contain anything different
is if btrfs_lookup_file_extent returned a positive value and the
previous item is different than an extent. Avoid this situation by
simply checking found_key.type rather than assigning the item type to
found_type intermittently. Also make the variable an u8 to reduce stack
usage. No functional changes.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 05c50a02d4ff47e31d0a1c85a242aa135fe83e10..902577d5fc8cd354ad9676442c0d042b62b8d213 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6740,7 +6740,7 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
        u64 extent_start = 0;
        u64 extent_end = 0;
        u64 objectid = btrfs_ino(inode);
-       u32 found_type;
+       u8 extent_type;
        struct btrfs_path *path = NULL;
        struct btrfs_root *root = inode->root;
        struct btrfs_file_extent_item *item;
@@ -6806,11 +6806,9 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
        leaf = path->nodes[0];
        item = btrfs_item_ptr(leaf, path->slots[0],
                              struct btrfs_file_extent_item);
-       /* are we inside the extent that was found? */
        btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-       found_type = found_key.type;
        if (found_key.objectid != objectid ||
-           found_type != BTRFS_EXTENT_DATA_KEY) {
+           found_key.type != BTRFS_EXTENT_DATA_KEY) {
                /*
                 * If we backup past the first extent we want to move forward
                 * and see if there is an extent in front of us, otherwise we'll
@@ -6821,16 +6819,16 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
                goto next;
        }
 
-       found_type = btrfs_file_extent_type(leaf, item);
+       extent_type = btrfs_file_extent_type(leaf, item);
        extent_start = found_key.offset;
-       if (found_type == BTRFS_FILE_EXTENT_REG ||
-           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+       if (extent_type == BTRFS_FILE_EXTENT_REG ||
+           extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
                extent_end = extent_start +
                       btrfs_file_extent_num_bytes(leaf, item);
 
                trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
                                                       extent_start);
-       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+       } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
                size_t size;
 
                size = btrfs_file_extent_ram_bytes(leaf, item);
@@ -6871,10 +6869,10 @@ next:
        btrfs_extent_item_to_extent_map(inode, path, item,
                        new_inline, em);
 
-       if (found_type == BTRFS_FILE_EXTENT_REG ||
-           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+       if (extent_type == BTRFS_FILE_EXTENT_REG ||
+           extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
                goto insert;
-       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+       } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
                unsigned long ptr;
                char *map;
                size_t size;