Support Linux 6.8 (#47)

To align with the best practices recommended by Linux kernel v6.8, this
commit replaces direct accesses to the '__i_atime' and '__i_mtime'
fields with the newly introduced accessor functions. Functions such as
'inode_get_atime_sec' and 'simple_inode_init_ts' now encapsulate direct
interactions with these inode fields. This change enhances code
readability and maintainability, ensures adherence to evolving kernel
API manners, and minimizes direct manipulation of internal structures,
thereby reducing potential for bugs and improving compatibility with
future kernel updates.

Author: jason50123

file.c

@@ -96,10 +96,19 @@ static int simplefs_readpage(struct file *file, struct page *page)
 /* Called by the page cache to write a dirty page to the physical disk (when
  * sync is called or when memory is needed).
  */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 8, 0)
+static int simplefs_writepage(struct page *page, struct writeback_control *wbc)
+{
+    struct folio *folio = page_folio(page);
+    return __block_write_full_folio(page->mapping->host, folio,
+                                    simplefs_file_get_block, wbc);
+}
+#else
 static int simplefs_writepage(struct page *page, struct writeback_control *wbc)
 {
     return block_write_full_page(page, simplefs_file_get_block, wbc);
 }
+#endif
 
 /* Called by the VFS when a write() syscall is made on a file, before writing
  * the data into the page cache. This function checks if the write operation
@@ -183,7 +192,11 @@ static int simplefs_write_end(struct file *file,
     /* Update inode metadata */
     inode->i_blocks = inode->i_size / SIMPLEFS_BLOCK_SIZE + 2;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    cur_time = current_time(inode);
+    inode_set_mtime_to_ts(inode, cur_time);
+    inode_set_ctime_to_ts(inode, cur_time);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(inode);
     inode->i_mtime = cur_time;
     inode_set_ctime_to_ts(inode, cur_time);

inode.c

@@ -63,10 +63,16 @@ struct inode *simplefs_iget(struct super_block *sb, unsigned long ino)
     inode->i_ctime.tv_nsec = 0;
 #endif
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    inode_set_atime(inode, (time64_t) le32_to_cpu(cinode->i_atime), 0);
+    inode_set_mtime(inode, (time64_t) le32_to_cpu(cinode->i_mtime), 0);
+#else
     inode->i_atime.tv_sec = (time64_t) le32_to_cpu(cinode->i_atime);
     inode->i_atime.tv_nsec = 0;
     inode->i_mtime.tv_sec = (time64_t) le32_to_cpu(cinode->i_mtime);
     inode->i_mtime.tv_nsec = 0;
+#endif
+
     inode->i_blocks = le32_to_cpu(cinode->i_blocks);
     set_nlink(inode, le32_to_cpu(cinode->i_nlink));
 
@@ -161,7 +167,12 @@ static struct dentry *simplefs_lookup(struct inode *dir,
     brelse(bh);
 
     /* Update directory access time */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    inode_set_atime_to_ts(dir, current_time(dir));
+#else
     dir->i_atime = current_time(dir);
+#endif
+
     mark_inode_dirty(dir);
 
     /* Fill the dentry with the inode */
@@ -219,7 +230,9 @@ static struct inode *simplefs_new_inode(struct inode *dir, mode_t mode)
 #endif
         set_nlink(inode, 1);
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+        simple_inode_init_ts(inode);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
         cur_time = current_time(inode);
         inode->i_atime = inode->i_mtime = cur_time;
         inode_set_ctime_to_ts(inode, cur_time);
@@ -261,7 +274,9 @@ static struct inode *simplefs_new_inode(struct inode *dir, mode_t mode)
         set_nlink(inode, 1);
     }
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    simple_inode_init_ts(inode);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(inode);
     inode->i_atime = inode->i_mtime = cur_time;
     inode_set_ctime_to_ts(inode, cur_time);
@@ -395,7 +410,9 @@ static int simplefs_create(struct inode *dir,
     /* Update stats and mark dir and new inode dirty */
     mark_inode_dirty(inode);
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    simple_inode_init_ts(dir);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(dir);
     dir->i_mtime = dir->i_atime = cur_time;
     inode_set_ctime_to_ts(dir, cur_time);
@@ -537,7 +554,9 @@ static int simplefs_unlink(struct inode *dir, struct dentry *dentry)
         goto clean_inode;
 
         /* Update inode stats */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    simple_inode_init_ts(dir);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(dir);
     dir->i_mtime = dir->i_atime = cur_time;
     inode_set_ctime_to_ts(dir, cur_time);
@@ -606,7 +625,11 @@ static int simplefs_unlink(struct inode *dir, struct dentry *dentry)
     i_gid_write(inode, 0);
     inode->i_mode = 0;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    inode_set_mtime(inode, 0, 0);
+    inode_set_atime(inode, 0, 0);
+    inode_set_ctime(inode, 0, 0);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     inode->i_mtime.tv_sec = inode->i_atime.tv_sec = 0;
     inode_set_ctime(inode, 0, 0);
 #else
@@ -750,7 +773,9 @@ static int simplefs_rename(struct inode *old_dir,
     brelse(bh2);
 
     /* Update new parent inode metadata */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    simple_inode_init_ts(new_dir);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(new_dir);
     new_dir->i_atime = new_dir->i_mtime = cur_time;
     inode_set_ctime_to_ts(new_dir, cur_time);
@@ -769,7 +794,9 @@ static int simplefs_rename(struct inode *old_dir,
         goto release_new;
 
         /* Update old parent inode metadata */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    simple_inode_init_ts(old_dir);
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 6, 0)
     cur_time = current_time(old_dir);
     old_dir->i_atime = old_dir->i_mtime = cur_time;
     inode_set_ctime_to_ts(old_dir, cur_time);

super.c

@@ -8,7 +8,11 @@
 #include <linux/statfs.h>
 
 #include "simplefs.h"
-
+struct dentry *simplefs_mount(struct file_system_type *fs_type,
+                              int flags,
+                              const char *dev_name,
+                              void *data);
+void simplefs_kill_sb(struct super_block *sb);
 static struct kmem_cache *simplefs_inode_cache;
 
 int simplefs_init_inode_cache(void)
@@ -78,8 +82,13 @@ static int simplefs_write_inode(struct inode *inode,
     disk_inode->i_ctime = inode->i_ctime.tv_sec;
 #endif
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
+    disk_inode->i_atime = inode_get_atime_sec(inode);
+    disk_inode->i_atime = inode_get_mtime_sec(inode);
+#else
     disk_inode->i_atime = inode->i_atime.tv_sec;
     disk_inode->i_mtime = inode->i_mtime.tv_sec;
+#endif
     disk_inode->i_blocks = inode->i_blocks;
     disk_inode->i_nlink = inode->i_nlink;
     disk_inode->ei_block = ci->ei_block;