btrfs: Return offset from find_desired_extent

Instead of using an input pointer parameter as the return value and have
an int as the return type of find_desired_extent, rework the function to
directly return the found offset. Doing that the 'ret' variable in
btrfs_llseek_file can be removed. Additional (subjective) benefit is
that btrfs' llseek function now resemebles those of the other major
filesystems.

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

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 949212289c891b2ee2a82c035a8cebf7791d1724..32e620981485700853404e3e896cbc25efafa204 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3351,7 +3351,8 @@ static long btrfs_fallocate(struct file *file, int mode,
        return ret;
 }
 
-static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
+static loff_t find_desired_extent(struct inode *inode, loff_t offset,
+                                 int whence)
 {
        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
        struct extent_map *em = NULL;
@@ -3363,14 +3364,14 @@ static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
        u64 len;
        int ret = 0;
 
-       if (i_size == 0 || *offset >= i_size)
+       if (i_size == 0 || offset >= i_size)
                return -ENXIO;
 
        /*
-        * *offset can be negative, in this case we start finding DATA/HOLE from
+        * offset can be negative, in this case we start finding DATA/HOLE from
         * the very start of the file.
         */
-       start = max_t(loff_t, 0, *offset);
+       start = max_t(loff_t, 0, offset);
 
        lockstart = round_down(start, fs_info->sectorsize);
        lockend = round_up(i_size, fs_info->sectorsize);
@@ -3405,21 +3406,23 @@ static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
                cond_resched();
        }
        free_extent_map(em);
-       if (!ret) {
+       unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+                            &cached_state);
+       if (ret) {
+               offset = ret;
+       } else {
                if (whence == SEEK_DATA && start >= i_size)
-                       ret = -ENXIO;
+                       offset = -ENXIO;
                else
-                       *offset = min_t(loff_t, start, i_size);
+                       offset = min_t(loff_t, start, i_size);
        }
-       unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
-                            &cached_state);
-       return ret;
+
+       return offset;
 }
 
 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
 {
        struct inode *inode = file->f_mapping->host;
-       int ret;
 
        switch (whence) {
        default:
@@ -3427,13 +3430,14 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
        case SEEK_DATA:
        case SEEK_HOLE:
                inode_lock_shared(inode);
-               ret = find_desired_extent(inode, &offset, whence);
+               offset = find_desired_extent(inode, offset, whence);
                inode_unlock_shared(inode);
-
-               if (ret)
-                       return ret;
+               break;
        }
 
+       if (offset < 0)
+               return offset;
+
        return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
 }