fuse: llseek optimize SEEK_CUR and SEEK_SET

Use generic_file_llseek() instead of open coding the seek function.

i_mutex protection is only necessary for SEEK_END (and SEEK_HOLE, SEEK_DATA), so
move SEEK_CUR and SEEK_SET out from under i_mutex.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 8 insertions, 40 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 0c84100acd44..e0b60acfe726 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1555,48 +1555,16 @@ static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
         loff_t retval;
         struct inode *inode = file->f_path.dentry->d_inode;
 
-        mutex_lock(&inode->i_mutex);
-        if (origin != SEEK_CUR && origin != SEEK_SET) {
-                retval = fuse_update_attributes(inode, NULL, file, NULL);
-                if (retval)
-                        goto exit;
-        }
+        /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
+        if (origin == SEEK_CUR || origin == SEEK_SET)
+                return generic_file_llseek(file, offset, origin);
 
-        switch (origin) {
-        case SEEK_END:
-                offset += i_size_read(inode);
-                break;
-        case SEEK_CUR:
-                if (offset == 0) {
-                        retval = file->f_pos;
-                        goto exit;
-                }
-                offset += file->f_pos;
-                break;
-        case SEEK_DATA:
-                if (offset >= i_size_read(inode)) {
-                        retval = -ENXIO;
-                        goto exit;
-                }
-                break;
-        case SEEK_HOLE:
-                if (offset >= i_size_read(inode)) {
-                        retval = -ENXIO;
-                        goto exit;
-                }
-                offset = i_size_read(inode);
-                break;
-        }
-        retval = -EINVAL;
-        if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
-                if (offset != file->f_pos) {
-                        file->f_pos = offset;
-                        file->f_version = 0;
-                }
-                retval = offset;
-        }
-exit:
+        mutex_lock(&inode->i_mutex);
+        retval = fuse_update_attributes(inode, NULL, file, NULL);
+        if (!retval)
+                retval = generic_file_llseek(file, offset, origin);
         mutex_unlock(&inode->i_mutex);
+
         return retval;
 }