Second Extended Filesystem (ext2) and other improvements (#33)

[lunaix-os.git] / lunaix-os / kernel / fs / ext2 / mount.c

diff --git a/lunaix-os/kernel/fs/ext2/mount.c b/lunaix-os/kernel/fs/ext2/mount.c
new file mode 100644 (file)
index 0000000..05fbdce
--- /dev/null
+++ b/lunaix-os/kernel/fs/ext2/mount.c
@@ -0,0 +1,230 @@
+#include <lunaix/fs/api.h>
+#include <lunaix/block.h>
+#include <lunaix/mm/valloc.h>
+#include <lunaix/mm/page.h>
+#include <lunaix/syslog.h>
+
+#include "ext2.h"
+
+LOG_MODULE("EXT2")
+
+#define EXT2_COMPRESSION    0x0001
+#define EXT2_FILETYPE       0x0002
+#define EXT2_JOURNAL        0x0004
+#define EXT2_METABG         0x0008
+
+#define EXT2_SPARSESB       0x0001
+#define EXT2_LARGEFLE       0x0002
+#define EXT2_BTREEDIR       0x0004
+
+#define EXT2_SUPER_MAGIC            0xef53
+#define EXT2_BASE_BLKSZ             1024
+#define EXT2_PRIME_SB_OFF           EXT2_BASE_BLKSZ
+
+// current support for incompatible features
+#define EXT2_IMPL_REQFEAT           (EXT2_FILETYPE)
+
+// current support for readonly feature
+#define EXT2_IMPL_ROFEAT            (EXT2_SPARSESB)
+
+#define EXT2_ROOT_INO               to_ext2ino_id(1)
+
+#define check_compat_mnt(feat) \
+        (!((feat) & ~EXT2_IMPL_REQFEAT))
+
+#define check_compat_mnt_ro_fallback(feat) \
+        (((feat) & ~EXT2_IMPL_ROFEAT))
+
+static size_t
+ext2_rd_capacity(struct v_superblock* vsb)
+{
+    struct ext2_sbinfo* sb = fsapi_impl_data(vsb, struct ext2_sbinfo);
+    return sb->raw->s_blk_cnt * fsapi_block_size(vsb);
+}
+
+static void
+__vsb_release(struct v_superblock* vsb)
+{
+    ext2gd_release_gdt(vsb);
+    vfree(vsb->data);
+}
+
+static size_t
+ext2_rd_usage(struct v_superblock* vsb)
+{
+    struct ext2_sbinfo* sb = fsapi_impl_data(vsb, struct ext2_sbinfo);
+    size_t used = sb->raw->s_free_blk_cnt - sb->raw->s_blk_cnt;
+    return used * fsapi_block_size(vsb);
+}
+
+struct fsapi_vsb_ops vsb_ops = {
+    .read_capacity = ext2_rd_capacity,
+    .read_usage = ext2_rd_usage,
+    .init_inode = ext2ino_init,
+    .release = __vsb_release
+};
+
+static inline unsigned int
+__translate_feature(struct ext2b_super* sb)
+{
+    unsigned int feature = 0;
+    unsigned int req, opt, ro;
+
+    req = sb->s_required_feat;
+    opt = sb->s_optional_feat;
+    ro  = sb->s_ro_feat;
+
+    if ((req & EXT2_COMPRESSION)) {
+        feature |= FEAT_COMPRESSION;
+    }
+
+    if ((req & EXT2_FILETYPE)) {
+        feature |= FEAT_FILETYPE;
+    }
+
+    if ((ro & EXT2_SPARSESB)) {
+        feature |= FEAT_SPARSE_SB;
+    }
+
+    if ((ro & EXT2_LARGEFLE)) {
+        feature |= FEAT_LARGE_FILE;
+    }
+
+    return feature;
+}
+
+static bool
+__check_mount(struct v_superblock* vsb, struct ext2b_super* sb)
+{
+    unsigned int req, opt, ro;
+
+    req = sb->s_required_feat;
+    opt = sb->s_optional_feat;
+    ro  = sb->s_ro_feat;
+    
+    if (sb->s_magic != EXT2_SUPER_MAGIC) {
+        ERROR("invalid magic: 0x%x", sb->s_magic);
+        return false;
+    }
+
+    if (!check_compat_mnt(req)) 
+    {
+        ERROR("unsupported feature: 0x%x, mount refused", req);
+        return false;
+    }
+
+    if (check_compat_mnt_ro_fallback(ro)) 
+    {
+        WARN("unsupported feature: 0x%x, mounted as readonly", ro);
+        fsapi_set_readonly_mount(vsb);
+    }
+
+#ifndef CONFIG_ARCH_BITS_64
+    if ((ro & EXT2_LARGEFLE)) {
+        WARN("large file not supported on 32bits machine");
+        fsapi_set_readonly_mount(vsb);
+    }
+#endif
+
+    return true;
+}
+
+static int 
+ext2_mount(struct v_superblock* vsb, struct v_dnode* mnt)
+{
+    struct device* bdev;
+    struct ext2_sbinfo* ext2sb;
+    struct ext2b_super* rawsb;
+    struct v_inode* root_inode;
+    bbuf_t buf;
+    size_t block_size;
+    int errno = 0;
+    unsigned int req_feat;
+
+    bdev = fsapi_blockdev(vsb);
+    ext2sb = vzalloc(sizeof(*ext2sb));
+    rawsb = vzalloc(sizeof(*rawsb));
+
+    errno = bdev->ops.read(bdev, rawsb, EXT2_PRIME_SB_OFF, sizeof(*rawsb));
+    if (errno < 0) {
+        goto failed;
+    }
+
+    block_size = EXT2_BASE_BLKSZ << rawsb->s_log_blk_size;
+    fsapi_begin_vsb_setup(vsb, block_size);
+    
+    if (!__check_mount(vsb, rawsb)) {
+        goto unsupported;
+    }
+
+    if (block_size > PAGE_SIZE) {
+        ERROR("block size must not greater than page size");
+        errno = EINVAL;
+        goto failed;
+    }
+
+    ext2sb->bdev = bdev;
+    ext2sb->block_size = block_size;
+    ext2sb->vsb = vsb;
+    ext2sb->read_only = fsapi_readonly_mount(vsb);
+    ext2sb->raw = rawsb;
+    ext2sb->all_feature = __translate_feature(rawsb);
+
+    fsapi_set_vsb_ops(vsb, &vsb_ops);
+    fsapi_complete_vsb_setup(vsb, ext2sb);
+
+    ext2gd_prepare_gdt(vsb);
+
+    root_inode = vfs_i_alloc(vsb);
+    ext2ino_fill(root_inode, EXT2_ROOT_INO);
+    vfs_assign_inode(mnt, root_inode);
+
+    // replace the superblock raw buffer with bcache managed one
+    buf = fsblock_get(vsb, ext2_datablock(vsb, 0));
+    if (block_size == EXT2_BASE_BLKSZ) {
+        ext2sb->raw = blkbuf_data(buf);
+    }
+    else {
+        ext2sb->raw = offset(blkbuf_data(buf), EXT2_BASE_BLKSZ);
+    }
+
+    ext2sb->buf = buf;
+    vfree(rawsb);
+    return 0;
+
+unsupported:
+    errno = ENOTSUP;
+
+failed:
+    vfree(ext2sb);
+    vfree(rawsb);
+    fsapi_reset_vsb(vsb);
+    return errno;
+}
+
+static int 
+ext2_umount(struct v_superblock* vsb)
+{
+    // sync all dirty buffers
+    if (!blkbuf_syncall(vsb->blks, false)) {
+        return EAGAIN;
+    }
+
+    ext2gd_release_gdt(vsb);
+
+    blkbuf_release(vsb->blks);
+    return 0;
+}
+
+static void
+ext2_init()
+{
+    struct filesystem* fs;
+    fs = fsapi_fs_declare("ext2", 0);
+
+    fsapi_fs_set_mntops(fs, ext2_mount, ext2_umount);
+    fsapi_fs_finalise(fs);
+
+    gdesc_bcache_zone = bcache_create_zone("ext2_gdesc");
+}
+EXPORT_FILE_SYSTEM(ext2fs, ext2_init);
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