Fix compile warnings for 16 bit machines
[lwext4.git] / lwext4 / ext4.c
index fb8b7f852c6f1bd53799e2da48a143e3e5b30a0f..0cdf045afcff648175034de89e8574107fc5fd17 100644 (file)
@@ -44,6 +44,7 @@
 #include "ext4_inode.h"
 #include "ext4_super.h"
 #include "ext4_dir_idx.h"
+#include "ext4_xattr.h"
 #include "ext4.h"
 
 #include <stdlib.h>
@@ -180,7 +181,7 @@ static int ext4_has_children(bool *has_children, struct ext4_inode_ref *enode)
 
 static int ext4_link(struct ext4_mountpoint *mp, struct ext4_inode_ref *parent,
                     struct ext4_inode_ref *child, const char *name,
-                    uint32_t name_len)
+                    uint32_t name_len, bool rename)
 {
        /* Check maximum name length */
        if (name_len > EXT4_DIRECTORY_FILENAME_LEN)
@@ -196,7 +197,7 @@ static int ext4_link(struct ext4_mountpoint *mp, struct ext4_inode_ref *parent,
         */
        if (ext4_inode_is_type(&mp->fs.sb, child->inode,
                               EXT4_INODE_MODE_DIRECTORY) &&
-           ext4_inode_get_links_count(child->inode) == 0) {
+           !rename) {
                rc = ext4_dir_add_entry(child, ".", strlen("."), child);
                if (rc != EOK) {
                        ext4_dir_remove_entry(parent, name, strlen(name));
@@ -231,6 +232,10 @@ static int ext4_link(struct ext4_mountpoint *mp, struct ext4_inode_ref *parent,
                child->dirty = true;
                parent->dirty = true;
        } else {
+               /*
+                * In case we want to rename a directory,
+                * we reset the original '..' pointer.
+                */
                if (ext4_inode_is_type(&mp->fs.sb, child->inode,
                                        EXT4_INODE_MODE_DIRECTORY)) {
                        int has_flag_index =
@@ -253,7 +258,7 @@ static int ext4_link(struct ext4_mountpoint *mp, struct ext4_inode_ref *parent,
 
                        } else {
 #if CONFIG_DIR_INDEX_ENABLE
-                               rc = ext4_dir_dx_reset_parent_inode(parent,
+                               rc = ext4_dir_dx_reset_parent_inode(child,
                                                parent->index);
                                if (rc != EOK)
                                        return rc;
@@ -263,7 +268,8 @@ static int ext4_link(struct ext4_mountpoint *mp, struct ext4_inode_ref *parent,
 
                        ext4_fs_inode_links_count_inc(parent);
                        parent->dirty = true;
-               } else {
+               }
+               if (!rename) {
                        ext4_fs_inode_links_count_inc(child);
                        child->dirty = true;
                }
@@ -284,7 +290,7 @@ static int ext4_unlink(struct ext4_mountpoint *mp,
 
        /* Cannot unlink non-empty node */
        if (has_children)
-               return ENOTSUP;
+               return ENOTEMPTY;
 
        /* Remove entry from parent directory */
        rc = ext4_dir_remove_entry(parent, name, name_len);
@@ -445,18 +451,25 @@ int ext4_umount(const char *mount_point)
        return ext4_block_fini(mp->fs.bdev);
 }
 
+static struct ext4_mountpoint *ext4_get_mount(const char *path)
+{
+       int i;
+       for (i = 0; i < CONFIG_EXT4_MOUNTPOINTS_COUNT; ++i) {
+
+               if (!_mp[i].mounted)
+                       continue;
+
+               if (!strncmp(_mp[i].name, path, strlen(_mp[i].name)))
+                       return &_mp[i];
+       }
+       return 0;
+}
+
 int ext4_mount_point_stats(const char *mount_point,
                           struct ext4_mount_stats *stats)
 {
-       uint32_t i;
-       struct ext4_mountpoint *mp = 0;
+       struct ext4_mountpoint *mp = ext4_get_mount(mount_point);
 
-       for (i = 0; i < CONFIG_EXT4_MOUNTPOINTS_COUNT; ++i) {
-               if (!strcmp(_mp[i].name, mount_point)) {
-                       mp = &_mp[i];
-                       break;
-               }
-       }
        if (!mp)
                return ENOENT;
 
@@ -498,20 +511,6 @@ int ext4_mount_setup_locks(const char *mount_point,
 
 /********************************FILE OPERATIONS*****************************/
 
-static struct ext4_mountpoint *ext4_get_mount(const char *path)
-{
-       int i;
-       for (i = 0; i < CONFIG_EXT4_MOUNTPOINTS_COUNT; ++i) {
-
-               if (!_mp[i].mounted)
-                       continue;
-
-               if (!strncmp(_mp[i].name, path, strlen(_mp[i].name)))
-                       return &_mp[i];
-       }
-       return 0;
-}
-
 static int ext4_path_check(const char *path, bool *is_goal)
 {
        int i;
@@ -574,7 +573,7 @@ static bool ext4_parse_flags(const char *flags, uint32_t *file_flags)
 }
 
 /*
- * NOTICE: if filetype is equal to EXT4_DIRECTORY_FILETYPE_UNKNOWN,
+ * NOTICE: if filetype is equal to EXT4_DIRENTRY_UNKNOWN,
  * any filetype of the target dir entry will be accepted.
  */
 static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
@@ -582,7 +581,7 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
                              uint32_t *name_off)
 {
        bool is_goal = false;
-       uint8_t inode_type = EXT4_DIRECTORY_FILETYPE_DIR;
+       uint8_t inode_type = EXT4_DIRENTRY_UNKNOWN;
        uint32_t next_inode;
 
        int r;
@@ -621,8 +620,8 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
                if (!len) {
                        /*If root open was request.*/
                        if (is_goal &&
-                           ((filetype == EXT4_DIRECTORY_FILETYPE_DIR) ||
-                            (filetype == EXT4_DIRECTORY_FILETYPE_UNKNOWN)))
+                           ((filetype == EXT4_DIRENTRY_DIR) ||
+                            (filetype == EXT4_DIRENTRY_UNKNOWN)))
                                break;
 
                        r = ENOENT;
@@ -632,6 +631,9 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
                r = ext4_dir_find_entry(&result, &ref, path, len);
                if (r != EOK) {
 
+                       /*Destroy last result*/
+                       ext4_dir_destroy_result(&ref, &result);
+
                        if (r != ENOENT)
                                break;
 
@@ -642,16 +644,14 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
                        struct ext4_inode_ref child_ref;
                        r = ext4_fs_alloc_inode(
                            &mp->fs, &child_ref,
-                           is_goal ? (filetype == EXT4_DIRECTORY_FILETYPE_DIR)
-                                   : true);
+                           is_goal ? filetype
+                                   : EXT4_DIRENTRY_DIR);
                        if (r != EOK)
                                break;
 
-                       /*Destroy last result*/
-                       ext4_dir_destroy_result(&ref, &result);
 
                        /*Link with root dir.*/
-                       r = ext4_link(mp, &ref, &child_ref, path, len);
+                       r = ext4_link(mp, &ref, &child_ref, path, len, false);
                        if (r != EOK) {
                                /*Fail. Free new inode.*/
                                ext4_fs_free_inode(&child_ref);
@@ -679,11 +679,11 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
                        break;
 
                /*If expected file error*/
-               if (inode_type != EXT4_DIRECTORY_FILETYPE_DIR && !is_goal) {
+               if (inode_type != EXT4_DIRENTRY_DIR && !is_goal) {
                        r = ENOENT;
                        break;
                }
-               if (filetype != EXT4_DIRECTORY_FILETYPE_UNKNOWN) {
+               if (filetype != EXT4_DIRENTRY_UNKNOWN) {
                        if ((inode_type != filetype) && is_goal) {
                                r = ENOENT;
                                break;
@@ -715,7 +715,7 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
        if (is_goal) {
 
                if ((f->flags & O_TRUNC) &&
-                   (inode_type == EXT4_DIRECTORY_FILETYPE_REG_FILE)) {
+                   (inode_type == EXT4_DIRENTRY_REG_FILE)) {
 
                        r = ext4_fs_truncate_inode(&ref, 0);
                        if (r != EOK) {
@@ -731,6 +731,7 @@ static int ext4_generic_open2(ext4_file *f, const char *path, int flags,
 
                if (f->flags & O_APPEND)
                        f->fpos = f->fsize;
+
        }
 
        r = ext4_fs_put_inode_ref(&ref);
@@ -749,19 +750,20 @@ static int ext4_generic_open(ext4_file *f, const char *path, const char *flags,
                return EINVAL;
 
        if (file_expect == true)
-               filetype = EXT4_DIRECTORY_FILETYPE_REG_FILE;
+               filetype = EXT4_DIRENTRY_REG_FILE;
        else
-               filetype = EXT4_DIRECTORY_FILETYPE_DIR;
+               filetype = EXT4_DIRENTRY_DIR;
 
        return ext4_generic_open2(f, path, iflags, filetype, parent_inode,
                                  name_off);
 }
 
 static int __ext4_create_hardlink(const char *path,
-               struct ext4_inode_ref *child_ref)
+               struct ext4_inode_ref *child_ref,
+               bool rename)
 {
        bool is_goal = false;
-       uint8_t inode_type = EXT4_DIRECTORY_FILETYPE_DIR;
+       uint8_t inode_type = EXT4_DIRENTRY_DIR;
        uint32_t next_inode;
 
        int r;
@@ -799,14 +801,19 @@ static int __ext4_create_hardlink(const char *path,
                r = ext4_dir_find_entry(&result, &ref, path, len);
                if (r != EOK) {
 
+                       /*Destroy last result*/
+                       ext4_dir_destroy_result(&ref, &result);
+
                        if (r != ENOENT || !is_goal)
                                break;
 
+                       /*Link with root dir.*/
+                       r = ext4_link(mp, &ref, child_ref, path, len, rename);
+                       break;
+               } else if (r == EOK && is_goal) {
                        /*Destroy last result*/
                        ext4_dir_destroy_result(&ref, &result);
-
-                       /*Link with root dir.*/
-                       r = ext4_link(mp, &ref, child_ref, path, len);
+                       r = EEXIST;
                        break;
                }
 
@@ -818,7 +825,7 @@ static int __ext4_create_hardlink(const char *path,
                if (r != EOK)
                        break;
 
-               if (inode_type == EXT4_DIRECTORY_FILETYPE_REG_FILE) {
+               if (inode_type == EXT4_DIRENTRY_REG_FILE) {
                        if (is_goal)
                                r = EEXIST;
                        else
@@ -850,10 +857,10 @@ static int __ext4_create_hardlink(const char *path,
        return r;
 }
 
-static int __ext4_remove_hardlink(const char *path,
-                                 uint32_t name_off,
-                                 struct ext4_inode_ref *parent_ref,
-                                 struct ext4_inode_ref *child_ref)
+static int ext4_remove_orig_reference(const char *path,
+                                     uint32_t name_off,
+                                     struct ext4_inode_ref *parent_ref,
+                                     struct ext4_inode_ref *child_ref)
 {
        bool is_goal;
        int r;
@@ -868,16 +875,17 @@ static int __ext4_remove_hardlink(const char *path,
 
        len = ext4_path_check(path, &is_goal);
 
-       /*Unlink from parent*/
-       r = ext4_unlink(mp, parent_ref, child_ref, path, len);
+       /* Remove entry from parent directory */
+       r = ext4_dir_remove_entry(parent_ref, path, len);
        if (r != EOK)
                goto Finish;
 
+       if (ext4_inode_is_type(&mp->fs.sb, child_ref->inode,
+                              EXT4_INODE_MODE_DIRECTORY)) {
+               ext4_fs_inode_links_count_dec(parent_ref);
+               parent_ref->dirty = true;
+       }
 Finish:
-       if (r != EOK)
-               ext4_fs_put_inode_ref(child_ref);
-
-       ext4_fs_put_inode_ref(parent_ref);
        return r;
 }
 
@@ -902,7 +910,7 @@ int ext4_flink(const char *path, const char *hardlink_path)
        EXT4_MP_LOCK(mp);
 
        r = ext4_generic_open2(&f, path, O_RDONLY,
-                              EXT4_DIRECTORY_FILETYPE_UNKNOWN,
+                              EXT4_DIRENTRY_UNKNOWN,
                               &parent_inode, &name_off);
        if (r != EOK)
                goto Finish;
@@ -917,7 +925,14 @@ int ext4_flink(const char *path, const char *hardlink_path)
 
        child_loaded = true;
 
-       r = __ext4_create_hardlink(hardlink_path, &child_ref);
+       /* Creating hardlink for directory is not allowed. */
+       if (ext4_inode_is_type(&mp->fs.sb, child_ref.inode,
+                              EXT4_INODE_MODE_DIRECTORY)) {
+               r = EINVAL;
+               goto Finish;
+       }
+
+       r = __ext4_create_hardlink(hardlink_path, &child_ref, false);
 
 Finish:
        if (child_loaded)
@@ -944,7 +959,7 @@ int ext4_frename(const char *path, const char *new_path)
        EXT4_MP_LOCK(mp);
 
        r = ext4_generic_open2(&f, path, O_RDONLY,
-                       EXT4_DIRECTORY_FILETYPE_UNKNOWN,
+                       EXT4_DIRENTRY_UNKNOWN,
                        &parent_inode, &name_off);
        if (r != EOK)
                goto Finish;
@@ -966,11 +981,12 @@ int ext4_frename(const char *path, const char *new_path)
 
        child_loaded = true;
 
-       r = __ext4_create_hardlink(new_path, &child_ref);
+       r = __ext4_create_hardlink(new_path, &child_ref, true);
        if (r != EOK)
                goto Finish;
 
-       r = __ext4_remove_hardlink(path, name_off, &parent_ref, &child_ref);
+       r = ext4_remove_orig_reference(path, name_off,
+                                      &parent_ref, &child_ref);
        if (r != EOK)
                goto Finish;
 
@@ -1028,7 +1044,9 @@ int ext4_fremove(const char *path)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
-       r = ext4_generic_open(&f, path, "r", true, &parent_inode, &name_off);
+       r = ext4_generic_open2(&f, path, O_RDWR,
+                              EXT4_DIRENTRY_UNKNOWN,
+                              &parent_inode, &name_off);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
                return r;
@@ -1061,7 +1079,6 @@ int ext4_fremove(const char *path)
 
        /*Link count is zero, the inode should be freed. */
        if (!ext4_inode_get_links_count(child.inode)) {
-               printf("ttttt\n");
                ext4_inode_set_deletion_time(child.inode, 0xFFFFFFFF);
                /*Turncate*/
                ext4_block_cache_write_back(mp->fs.bdev, 1);
@@ -1084,18 +1101,32 @@ Finish:
        return r;
 }
 
-int ext4_fill_raw_inode(const char *mount_point, uint32_t ino,
+int ext4_fill_raw_inode(const char *path,
+                       uint32_t *ret_ino,
                        struct ext4_inode *inode)
 {
        int r;
+       ext4_file f;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = ext4_get_mount(mount_point);
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
+       uint32_t ino;
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
+       r = ext4_generic_open2(&f, path, O_RDONLY,
+                              EXT4_DIRENTRY_UNKNOWN,
+                              NULL, NULL);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+
+       ino = f.inode;
+       ext4_fclose(&f);
+
        /*Load parent*/
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
@@ -1107,6 +1138,10 @@ int ext4_fill_raw_inode(const char *mount_point, uint32_t ino,
 
        ext4_fs_put_inode_ref(&inode_ref);
        EXT4_MP_UNLOCK(mp);
+
+       if (ret_ino)
+               *ret_ino = ino;
+
        return r;
 }
 
@@ -1126,7 +1161,7 @@ int ext4_fopen(ext4_file *f, const char *path, const char *flags)
        return r;
 }
 
-int ext4_fopen2(ext4_file *f, const char *path, int flags, bool file_expect)
+int ext4_fopen2(ext4_file *f, const char *path, int flags)
 {
        struct ext4_mountpoint *mp = ext4_get_mount(path);
        int r;
@@ -1135,10 +1170,7 @@ int ext4_fopen2(ext4_file *f, const char *path, int flags, bool file_expect)
        if (!mp)
                return ENOENT;
 
-       if (file_expect == true)
-               filetype = EXT4_DIRECTORY_FILETYPE_REG_FILE;
-       else
-               filetype = EXT4_DIRECTORY_FILETYPE_DIR;
+        filetype = EXT4_DIRENTRY_REG_FILE;
 
        EXT4_MP_LOCK(mp);
        ext4_block_cache_write_back(mp->fs.bdev, 1);
@@ -1179,23 +1211,6 @@ static int ext4_ftruncate_no_lock(ext4_file *f, uint64_t size)
                goto Finish;
        }
 
-       if ((ext4_inode_get_mode(&f->mp->fs.sb, ref.inode) & EXT4_INODE_MODE_SOFTLINK)
-                       == EXT4_INODE_MODE_SOFTLINK
-                       && f->fsize < sizeof(ref.inode->blocks)
-                       && !ext4_inode_get_blocks_count(&f->mp->fs.sb, ref.inode)) {
-               char *content = (char *)ref.inode->blocks;
-               memset(content + size, 0, sizeof(ref.inode->blocks) - size);
-               ext4_inode_set_size(ref.inode, size);
-               ref.dirty = true;
-
-               f->fsize = size;
-               if (f->fpos > size)
-                       f->fpos = size;
-
-               r = EOK;
-               goto Finish;
-       }
-
        /*Start write back cache mode.*/
        r = ext4_block_cache_write_back(f->mp->fs.bdev, 1);
        if (r != EOK)
@@ -1279,6 +1294,30 @@ int ext4_fread(ext4_file *f, void *buf, size_t size, size_t *rcnt)
        sblock_end = (f->fpos + size) / block_size;
        u = (f->fpos) % block_size;
 
+       /*If the size of symlink is smaller than 60 bytes*/
+       if (ext4_inode_is_type(&f->mp->fs.sb, ref.inode, EXT4_INODE_MODE_SOFTLINK)
+                       && f->fsize < sizeof(ref.inode->blocks)
+                       && !ext4_inode_get_blocks_count(&f->mp->fs.sb, ref.inode)) {
+               char *content = (char *)ref.inode->blocks;
+               if (f->fpos < f->fsize) {
+                       r = (u + size > f->fsize)
+                               ?(f->fsize - u)
+                               :(size);
+                       memcpy(buf, content + u, r);
+                       if (rcnt)
+                               *rcnt = r;
+
+               } else {
+                       r = 0;
+                       if (rcnt)
+                               *rcnt = 0;
+
+               }
+
+               r = EOK;
+               goto Finish;
+       }
+
        if (u) {
 
                uint32_t ll = size > (block_size - u) ? (block_size - u) : size;
@@ -1577,27 +1616,34 @@ uint64_t ext4_ftell(ext4_file *f) { return f->fpos; }
 
 uint64_t ext4_fsize(ext4_file *f) { return f->fsize; }
 
-int ext4_fchmod(ext4_file *f, uint32_t mode)
+int ext4_chmod(const char *path, uint32_t mode)
 {
        int r;
        uint32_t ino;
+       ext4_file f;
        struct ext4_sblock *sb;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = f->mp;
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
-       ino = f->inode;
+       r = ext4_generic_open2(&f, path, O_RDWR, EXT4_DIRENTRY_UNKNOWN, 0, 0);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+       ino = f.inode;
+       sb = &mp->fs.sb;
+       ext4_fclose(&f);
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
                return r;
        }
 
-       sb = &f->mp->fs.sb;
        ext4_inode_set_mode(sb, inode_ref.inode, mode);
        inode_ref.dirty = true;
 
@@ -1606,19 +1652,26 @@ int ext4_fchmod(ext4_file *f, uint32_t mode)
        return r;
 }
 
-int ext4_fchown(ext4_file *f, uint32_t uid, uint32_t gid)
+int ext4_chown(const char *path, uint32_t uid, uint32_t gid)
 {
        int r;
+       ext4_file f;
        uint32_t ino;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = f->mp;
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
-       ino = f->inode;
+       r = ext4_generic_open2(&f, path, O_RDWR, EXT4_DIRENTRY_UNKNOWN, 0, 0);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+       ino = f.inode;
+       ext4_fclose(&f);
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
@@ -1634,19 +1687,26 @@ int ext4_fchown(ext4_file *f, uint32_t uid, uint32_t gid)
        return r;
 }
 
-int ext4_file_set_atime(ext4_file *f, uint32_t atime)
+int ext4_file_set_atime(const char *path, uint32_t atime)
 {
        int r;
+       ext4_file f;
        uint32_t ino;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = f->mp;
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
-       ino = f->inode;
+       r = ext4_generic_open2(&f, path, O_RDWR, EXT4_DIRENTRY_UNKNOWN, 0, 0);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+       ino = f.inode;
+       ext4_fclose(&f);
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
@@ -1661,19 +1721,26 @@ int ext4_file_set_atime(ext4_file *f, uint32_t atime)
        return r;
 }
 
-int ext4_file_set_mtime(ext4_file *f, uint32_t mtime)
+int ext4_file_set_mtime(const char *path, uint32_t mtime)
 {
        int r;
+       ext4_file f;
        uint32_t ino;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = f->mp;
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
-       ino = f->inode;
+       r = ext4_generic_open2(&f, path, O_RDWR, EXT4_DIRENTRY_UNKNOWN, 0, 0);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+       ino = f.inode;
+       ext4_fclose(&f);
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
@@ -1688,19 +1755,26 @@ int ext4_file_set_mtime(ext4_file *f, uint32_t mtime)
        return r;
 }
 
-int ext4_file_set_ctime(ext4_file *f, uint32_t ctime)
+int ext4_file_set_ctime(const char *path, uint32_t ctime)
 {
        int r;
+       ext4_file f;
        uint32_t ino;
        struct ext4_inode_ref inode_ref;
-       struct ext4_mountpoint *mp = f->mp;
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
 
        if (!mp)
                return ENOENT;
 
        EXT4_MP_LOCK(mp);
 
-       ino = f->inode;
+       r = ext4_generic_open2(&f, path, O_RDWR, EXT4_DIRENTRY_UNKNOWN, 0, 0);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(mp);
+               return r;
+       }
+       ino = f.inode;
+       ext4_fclose(&f);
        r = ext4_fs_get_inode_ref(&mp->fs, ino, &inode_ref);
        if (r != EOK) {
                EXT4_MP_UNLOCK(mp);
@@ -1715,6 +1789,142 @@ int ext4_file_set_ctime(ext4_file *f, uint32_t ctime)
        return r;
 }
 
+static int ext4_fsymlink_set(ext4_file *f, const void *buf, uint32_t size)
+{
+       struct ext4_block b;
+       struct ext4_inode_ref ref;
+       uint32_t sblock, fblock;
+       uint32_t block_size;
+       int r;
+
+       ext4_assert(f && f->mp);
+
+       if (!size)
+               return EOK;
+
+       r = ext4_fs_get_inode_ref(&f->mp->fs, f->inode, &ref);
+       if (r != EOK) {
+               EXT4_MP_UNLOCK(f->mp);
+               return r;
+       }
+
+       /*Sync file size*/
+       block_size = ext4_sb_get_block_size(&f->mp->fs.sb);
+       if (size > block_size) {
+               r = EINVAL;
+               goto Finish;
+       }
+       r = ext4_ftruncate_no_lock(f, 0);
+       if (r != EOK)
+               goto Finish;
+
+       /*Start write back cache mode.*/
+       r = ext4_block_cache_write_back(f->mp->fs.bdev, 1);
+       if (r != EOK)
+               goto Finish;
+
+       /*If the size of symlink is smaller than 60 bytes*/
+       if (size < sizeof(ref.inode->blocks)) {
+               char *content = (char *)ref.inode->blocks;
+               memset(content, 0, sizeof(ref.inode->blocks));
+               memcpy(content, buf, size);
+               ext4_inode_clear_flag(ref.inode, EXT4_INODE_FLAG_EXTENTS);
+       } else {
+               ext4_fs_inode_blocks_init(&f->mp->fs, &ref);
+               r = ext4_fs_append_inode_block(&ref, &fblock, &sblock);
+               if (r != EOK)
+                       goto Finish;
+
+               r = ext4_block_get(f->mp->fs.bdev, &b, fblock);
+               if (r != EOK)
+                       goto Finish;
+
+               memcpy(b.data, buf, size);
+               b.dirty = true;
+               r = ext4_block_set(f->mp->fs.bdev, &b);
+               if (r != EOK)
+                       goto Finish;
+       }
+
+       /*Stop write back cache mode*/
+       ext4_block_cache_write_back(f->mp->fs.bdev, 0);
+
+       if (r != EOK)
+               goto Finish;
+
+       ext4_inode_set_size(ref.inode, size);
+       ref.dirty = true;
+
+       f->fsize = size;
+       if (f->fpos > size)
+               f->fpos = size;
+
+Finish:
+       ext4_fs_put_inode_ref(&ref);
+       return r;
+}
+
+int ext4_fsymlink(const char *target, const char *path)
+{
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
+       int r;
+       ext4_file f;
+       int filetype;
+
+       if (!mp)
+               return ENOENT;
+
+       filetype = EXT4_DIRENTRY_SYMLINK;
+
+       EXT4_MP_LOCK(mp);
+       ext4_block_cache_write_back(mp->fs.bdev, 1);
+       r = ext4_generic_open2(&f, path, O_RDWR|O_CREAT, filetype, 0, 0);
+       if (r == EOK)
+               r = ext4_fsymlink_set(&f, target, strlen(target));
+       else
+               goto Finish;
+
+       ext4_fclose(&f);
+
+Finish:
+       ext4_block_cache_write_back(mp->fs.bdev, 0);
+       EXT4_MP_UNLOCK(mp);
+       return r;
+}
+
+int ext4_readlink(const char *path, char *buf, size_t bufsize, size_t *rcnt)
+{
+       struct ext4_mountpoint *mp = ext4_get_mount(path);
+       int r;
+       ext4_file f;
+       int filetype;
+
+       if (!mp)
+               return ENOENT;
+
+       if (!buf)
+               return EINVAL;
+
+       memset(buf, 0, sizeof(bufsize));
+
+       filetype = EXT4_DIRENTRY_SYMLINK;
+
+       EXT4_MP_LOCK(mp);
+       ext4_block_cache_write_back(mp->fs.bdev, 1);
+       r = ext4_generic_open2(&f, path, O_RDONLY, filetype, 0, 0);
+       if (r == EOK)
+               r = ext4_fread(&f, buf, bufsize, rcnt);
+       else
+               goto Finish;
+
+       ext4_fclose(&f);
+
+Finish:
+       ext4_block_cache_write_back(mp->fs.bdev, 0);
+       EXT4_MP_UNLOCK(mp);
+       return r;
+}
+
 /*********************************DIRECTORY OPERATION************************/
 
 int ext4_dir_rm(const char *path)
@@ -1965,7 +2175,10 @@ int ext4_dir_open(ext4_dir *d, const char *path)
        return r;
 }
 
-int ext4_dir_close(ext4_dir *d) { return ext4_fclose(&d->f); }
+int ext4_dir_close(ext4_dir *d)
+{
+    return ext4_fclose(&d->f);
+}
 
 const ext4_direntry *ext4_dir_entry_next(ext4_dir *d)
 {
@@ -2010,6 +2223,11 @@ Finish:
        return de;
 }
 
+void ext4_dir_entry_rewind(ext4_dir *d)
+{
+    d->next_off = 0;
+}
+
 /**
  * @}
  */