vfs: remove g_fat_root global, allocate root per mount (P3.1, P3.2, P3.3)

- Remove g_fat_root global from fat.c
- Allocate root node dynamically in fat_mount() and ext2_mount()
- Add root field to vfs_superblock_t for cleanup on umount
- Update fat_kill_sb and ext2_kill_sb to free root node
- Remove g_fat_root check from fat_close_impl

diff --git a/include/fs.h b/include/fs.h
index c1ea44a1b36dfb761cefbb82f5dc309447cebb7c..d4238b1bb89e0492105fe043826990ca2cbd8242 100644 (file)
--- a/include/fs.h
+++ b/include/fs.h
@@ -42,6 +42,7 @@ typedef struct vfs_superblock {
     const block_device_t* bdev;          /* Block device (NULL for virtual FS) */
     uint32_t lba;                        /* Partition start LBA (0 for whole disk) */
     void* private_data;                  /* Filesystem-specific data (e.g. fat_mount, ext2_mount) */
+    struct fs_node* root;                /* VFS root node (for cleanup on umount) */
 } vfs_superblock_t;
 
 /* Mount result structure - returned by filesystem mount functions */

diff --git a/src/kernel/ext2.c b/src/kernel/ext2.c
index 02f60c439ae3a536731ba0cfa71d35540ad28263..829401d361532bc2dbc9b37a553858dfb11cba42 100644 (file)
--- a/src/kernel/ext2.c
+++ b/src/kernel/ext2.c
@@ -1552,6 +1552,7 @@ vfs_mount_result_t ext2_mount(const block_device_t* bdev, uint32_t partition_lba
     vfs_sb->bdev = bdev;
     vfs_sb->lba = partition_lba;
     vfs_sb->private_data = em;
+    vfs_sb->root = &root->vfs;
     /* fstype will be set by caller */
 
     kprintf("[EXT2] Mounted at LBA %u (%u blocks, %u inodes, %u groups, %uB/block)\n",

diff --git a/src/kernel/fat.c b/src/kernel/fat.c
index 6e3839bd8fa036c75fe7fbbc381181d2397cd408..cbcf5b4b307f49389fe1aa325b24978b50e67434 100644 (file)
--- a/src/kernel/fat.c
+++ b/src/kernel/fat.c
@@ -112,7 +112,6 @@ struct fat_node {
     uint32_t dir_entry_offset;    /* byte offset of dirent within parent dir data */
 };
 
-static struct fat_node g_fat_root;
 static uint8_t g_sec_buf[FAT_SECTOR_SIZE];
 
 /* ---- Low-level sector I/O ---- */
@@ -516,7 +515,6 @@ static const struct inode_operations fat_dir_iops = {
 static void fat_close_impl(fs_node_t* node) {
     if (!node) return;
     struct fat_node* fn = (struct fat_node*)node;
-    if (fn == &g_fat_root) return;
     kfree(fn);
 }
 
@@ -1210,21 +1208,28 @@ vfs_mount_result_t fat_mount(const block_device_t* bdev, uint32_t partition_lba)
     }
 
     /* Build root node */
-    memset(&g_fat_root, 0, sizeof(g_fat_root));
-    g_fat_root.mount = fm;
-    memcpy(g_fat_root.vfs.name, "fat", 4);
-    g_fat_root.vfs.flags = FS_DIRECTORY;
-    g_fat_root.vfs.inode = 0;
-    g_fat_root.first_cluster = (fm->type == FAT_TYPE_32) ? fm->root_cluster : 0;
-    g_fat_root.parent_cluster = 0;
-    g_fat_root.dir_entry_offset = 0;
-    g_fat_root.vfs.f_ops = &fat_dir_fops;
-    g_fat_root.vfs.i_ops = &fat_dir_iops;
+    struct fat_node* root = (struct fat_node*)kmalloc(sizeof(struct fat_node));
+    if (!root) {
+        kprintf("[FAT] Failed to allocate root node\n");
+        kfree(fm);
+        return result;
+    }
+    memset(root, 0, sizeof(*root));
+    root->mount = fm;
+    memcpy(root->vfs.name, "fat", 4);
+    root->vfs.flags = FS_DIRECTORY;
+    root->vfs.inode = 0;
+    root->first_cluster = (fm->type == FAT_TYPE_32) ? fm->root_cluster : 0;
+    root->parent_cluster = 0;
+    root->dir_entry_offset = 0;
+    root->vfs.f_ops = &fat_dir_fops;
+    root->vfs.i_ops = &fat_dir_iops;
 
     /* Build superblock */
     vfs_superblock_t* sb = (vfs_superblock_t*)kmalloc(sizeof(vfs_superblock_t));
     if (!sb) {
         kprintf("[FAT] Failed to allocate superblock\n");
+        kfree(root);
         kfree(fm);
         return result;
     }
@@ -1232,12 +1237,13 @@ vfs_mount_result_t fat_mount(const block_device_t* bdev, uint32_t partition_lba)
     sb->bdev = bdev;
     sb->lba = partition_lba;
     sb->private_data = fm;
+    sb->root = &root->vfs;
     /* fstype will be set by caller */
 
     kprintf("[FAT] Mounted FAT%u at LBA %u (%u clusters)\n",
             (unsigned)fm->type, partition_lba, fm->total_clusters);
 
-    result.root = &g_fat_root.vfs;
+    result.root = &root->vfs;
     result.sb = sb;
     return result;
 }

diff --git a/src/kernel/init.c b/src/kernel/init.c
index 47c29c47daed7bcc606faebc796c3e902ec85857..591252f2808034964cfa476fe39815cfa8f61105 100644 (file)
--- a/src/kernel/init.c
+++ b/src/kernel/init.c
@@ -97,15 +97,29 @@ int init_mount_fs(const char* fstype, const block_device_t* bdev, uint32_t lba,
 }
 
 static void fat_kill_sb(vfs_superblock_t* sb) {
-    if (sb && sb->private_data) {
-        fat_umount((struct fat_mount*)sb->private_data);
+    if (sb) {
+        /* Free the root node allocated in fat_mount */
+        if (sb->root) {
+            kfree(sb->root);
+        }
+        /* Free the mount structure */
+        if (sb->private_data) {
+            fat_umount((struct fat_mount*)sb->private_data);
+        }
         kfree(sb);
     }
 }
 
 static void ext2_kill_sb(vfs_superblock_t* sb) {
-    if (sb && sb->private_data) {
-        ext2_umount((struct ext2_mount*)sb->private_data);
+    if (sb) {
+        /* Free the root node allocated in ext2_mount */
+        if (sb->root) {
+            kfree(sb->root);
+        }
+        /* Free the mount structure */
+        if (sb->private_data) {
+            ext2_umount((struct ext2_mount*)sb->private_data);
+        }
         kfree(sb);
     }
 }