Lab09 filesystems2

Documentation/teaching/labs/filesystems_part2.rst

@@ -477,7 +477,7 @@ In the minix case, the function is ``minix_lookup``.
 This function is called indirectly when information about the inode associated with an entry in a directory is needed.
 Such a function performs the following operations:
 
-  #. Searces in the directory indicated by ``dir`` the entry having the name ``dentry->d_name.name``.
+  #. Searches in the directory indicated by ``dir`` the entry having the name ``dentry->d_name.name``.
   #. If the entry is found, it will return ``NULL`` and associate the inode with the name using the :c:func:`d_add` function.
   #. Otherwise, returns ``ERR_PTR``.
 

Documentation/teaching/so2/assign-collaboration.rst

@@ -0,0 +1,144 @@
+=============
+Collaboration
+=============
+
+Collaboration is essential in open source world and we encourage you
+to pick a team partner to work on selected assignments.
+
+Here is a simple guide to get you started:
+
+1. Use Github / Gitlab
+----------------------
+
+Best way to share your work inside the team is to use a version control system (VCS)
+in order to track each change. Mind that you must make your repo private and only allow
+read/write access rights to team members.
+
+2. Start with a skeleton for the assignment
+-------------------------------------------
+
+Add `init`/`exit` functions, driver operations and global structures that you driver might need.
+
+.. code-block:: c
+
+  // SPDX-License-Identifier: GPL-2.0
+  /*
+   * uart16550.c - UART16550 driver
+   *
+   * Author: John Doe <john.doe@mail.com>
+   * Author: Ionut Popescu <ionut.popescu@mail.com>
+   */
+  struct uart16550_dev {
+     struct cdev cdev;
+     /*TODO */
+  };
+
+  static struct uart16550_dev devs[MAX_NUMBER_DEVICES];
+
+  static int uart16550_open(struct inode *inode, struct file *file)
+  {
+      /*TODO */
+      return 0;
+  }
+
+  static int uart16550_release(struct inode *inode, struct file *file)
+  {
+     /*TODO */
+     return 0;
+  }
+
+  static ssize_t uart16550_read(struct file *file,  char __user *user_buffer,
+                                size_t size, loff_t *offset)
+  {
+        /*TODO */
+  }
+
+  static ssize_t uart16550_write(struct file *file,
+                                 const char __user *user_buffer,
+                                 size_t size, loff_t *offset)
+  {
+       /*TODO */
+  }
+
+  static long
+  uart16550_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+  {
+        /*TODO */
+        return 0;
+  }
+
+  static const struct file_operations uart16550_fops = {
+         .owner		 = THIS_MODULE,
+         .open		 = uart16550_open,
+         .release	 = uart16550_release,
+         .read		 = uart16550_read,
+         .write		 = uart16550_write,
+         .unlocked_ioctl = uart16550_ioctl
+  };
+
+  static int __init uart16550_init(void)
+  {
+    /* TODO: */
+  }
+
+  static void __exit uart16550_exit(void)
+  {
+     /* TODO: */
+  }
+
+  module_init(uart16550_init);
+  module_exit(uart16550_exit);
+
+  MODULE_DESCRIPTION("UART16550 Driver");
+  MODULE_AUTHOR("John Doe <john.doe@mail.com");
+  MODULE_AUTHOR("Ionut Popescu <ionut.popescu@mail.com");
+
+3. Add a commit for each individual change
+------------------------------------------
+
+First commit must always be the skeleton file. And the rest of the code should be on top of skeleton file.
+Please write a good commit mesage. Explain briefly what the commit does and *why* it is necessary.
+
+Follow the seven rules of writing a good commit message: https://cbea.ms/git-commit/#seven-rules
+
+.. code-block:: console
+
+  Commit 3c92a02cc52700d2cd7c50a20297eef8553c207a (HEAD -> tema2)
+  Author: John Doe <john.doe@mail.com>
+  Date:   Mon Apr 4 11:54:39 2022 +0300
+
+    uart16550: Add initial skeleton for ssignment #2
+
+    This adds simple skeleton file for uart16550 assignment. Notice
+    module init/exit callbacks and file_operations dummy implementation
+    for open/release/read/write/ioctl.
+
+    Signed-off-by: John Doe <john.doe@mail.com>
+
+4. Split the work inside the team
+---------------------------------
+
+Add `TODOs` with each team member tasks. Try to split the work evenly.
+
+Before starting to code, make a plan. On top of your skeleton file, add TODOs with each member tasks. Agree on global
+structures and the overlall driver design. Then start coding.
+
+5. Do reviews
+-------------
+
+Create Pull Requests with your commits and go through review rounds with your team members. You can follow `How to create a PR` `video <https://www.youtube.com/watch?v=YvoHJJWvn98>`_.
+
+6. Merge the work
+-----------------
+
+The final work is the result of merging all the pull requests. Following the commit messages
+one should clearly understand the progress of the code and how the work was managed inside the team.
+
+.. code-block:: console
+
+  f5118b873294 uart16550: Add uart16550_interrupt implementation
+  2115503fc3e3 uart16550: Add uart16550_ioctl implementation
+  b31a257fd8b8 uart16550: Add uart16550_write implementation
+  ac1af6d88a25 uart16550: Add uart16550_read implementation
+  9f680e8136bf uart16550: Add uart16550_open/release implementation
+  3c92a02cc527 uart16550: Add skeleton for SO2 assignment #2

Documentation/teaching/so2/index.rst

@@ -41,6 +41,7 @@ Operating Systems 2
    :caption: Assignments
    :maxdepth: 1
 
+   assign-collaboration.rst
    assign0-kernel-api.rst
    assign1-kprobe-based-tracer.rst
    assign2-driver-uart.rst

tools/labs/skels/filesystems/Lab08.md

@@ -0,0 +1,95 @@
+# Laborator  8
+
+## myfs
+### Exercitiul 1
+Structura `file_system_type` a fost initializata pentru sistemul de fisiere virtual `myfs`. In functia de mount specifica acestuia am folosit `mount_nodev` intrucat filesystem-ul este virtual si nu are nevoie de suport fizic. In functiile de init si exit ale modulului am inregistrat/eliminat sistemul de fisiere.
+
+Corectitudinea implementarii am verificat-o prin urmatoarea serie de comenzi in masina virtuala:
+
+```
+root@qemux86:~/skels/filesystems/myfs# insmod myfs.ko
+myfs: loading out-of-tree module taints kernel.
+register_filesystem successful
+root@qemux86:~/skels/filesystems/myfs# cat /proc/filesystems | grep myfs
+nodev   myfs
+root@qemux86:~/skels/filesystems/myfs# mkdir -p /mnt/myfs
+root@qemux86:~/skels/filesystems/myfs# mount -t myfs none /mnt/myfs
+root inode has 1 link(s)
+mount: mounting none on /mnt/myfs failed: Not a directory
+
+```
+
+### Exercitiul 2
+In structura de tipul `super_operations` am definit functiile superblock-ului utilizandu-le pe cele generice `generic_delete_inode()` si `simple_statfs()` pentru o functionalitate minimala. Dupa aceea am completat functia `fill_super` completand restul campurilor din superblock.
+
+### Exercitiul 3
+Completand functia `myfs_get_inode` am initializat inode-ul radacina. Prelunad informatiile din namespace-ul root am completat campurile `uid`, `gid` si `mode` ale inode-ului. Fiind un director, am adaugat operatiile specifice si am incrementat numarul de link-uri.
+
+### Exercitiul 4
+Corectitudinea rezolvarii se poate observa din outputul urmator:
+
+```
+root@qemux86:~/skels/filesystems/myfs# mkdir -p /mnt/myfs
+root@qemux86:~/skels/filesystems/myfs# mount -t myfs none /mnt/myfs
+root inode has 2 link(s)
+root@qemux86:~/skels/filesystems/myfs# cat /proc/mounts | grep myfs
+none /mnt/myfs myfs rw,relatime 0 0
+root@qemux86:~/skels/filesystems/myfs# ls -di /mnt/myfs/
+   4282 /mnt/myfs/
+root@qemux86:~/skels/filesystems/myfs# stat -f /mnt/myfs
+  File: "/mnt/myfs"
+    ID: 0        Namelen: 255     Type: UNKNOWN
+Block size: 4096
+Blocks: Total: 0          Free: 0          Available: 0
+Inodes: Total: 0          Free: 0
+root@qemux86:~/skels/filesystems/myfs# ls -la /mnt/myfs
+drwxr-xr-x    2 root     root             0 Apr 30 12:52 .
+drwxr-xr-x    3 root     root          1024 Apr 28 10:36 ..
+root@qemux86:~/skels/filesystems/myfs# touch /mnt/myfs/a.txt
+touch: /mnt/myfs/a.txt: Permission denied
+root@qemux86:~/skels/filesystems/myfs# umount /mnt/myfs
+```
+
+## minfs
+
+### Exercitiul 1
+In functia de mount `myfs_mount` am folosit `mount_bdev` intrucat filesystem-ul este nu mai este virtual ci are nevoie de suport fizic. Campul `fs_flags` al structurii de tipul `file_system_type` are valoarea `FS_REQUIRES_DEV` pentru a indica un filesystem ce utilizeaza un disk.
+
+Verificam ca filesystem-ul a fost creat cu succes:
+```
+root@qemux86:~/skels/filesystems/minfs/kernel# cat /proc/filesystems | grep minfs
+nodev   minfs
+```
+## Exercitiul 2
+Cu ajutorul functiei `sb_bread` citim block-ul de la index 0, campului `b_data` i se face cast la structura de tip superblock `struct minfs_super_block` (structura custom) si se verifica valoarea magic number-ului. Se copiaza valorile obtinute in superblock-ul generic si in structura de tipul `struct minfs_sb_info`.
+
+## Exercitiul 3
+Am completat functiile `minfs_alloc_inode` populand campul `vfs_inode` al structurii alocate folosind functia `inode_init_once`. Conform functiei utilizate,initializare se face o singura data, campurile inode-ului fiind **idempotent** (nu se modifica in urma operatiilor). Apoi am completat functia de dezalocare asociata.
+
+## Exercitiul 4
+Cu ajutorul functiei `sb_bread` citim block-ul de la index 1, apoi extragem inode-ul de index-ul `ino`. Am completat campurile `uid`, `gid`, `mode` si `size` ale variabilei `inode` (VFS inode). In cazul in care inode-ul este director, atunci se completeaza si campurile `i_op` si `i_fop` si incrementam numarul de link-uri.
+
+Acum inlocuim apelul functiei `myfs_get_inode` cu aceasta functie `minfs_iget`.
+
+## Exercitiul 5
+Testam corectitudinea implementarii:
+
+Setup:
+```
+root@qemux86:~/skels/filesystems/minfs/user# ./mkfs.minfs /dev/vdd
+root@qemux86:~/skels/filesystems/minfs/user# cd
+root@qemux86:~# cd skels/filesystems/minfs/kernel/
+root@qemux86:~/skels/filesystems/minfs/kernel# insmod minfs.ko
+minfs: loading out-of-tree module taints kernel.
+root@qemux86:~/skels/filesystems/minfs/kernel# mkdir -p /mnt/minfs/
+```
+```
+root@qemux86:~/skels/filesystems/minfs/user# ./test-minfs.sh
++ insmod ../kernel/minfs.ko
++ mkdir -p /mnt/minfs
++ ./mkfs.minfs /dev/vdb
++ mount -t minfs /dev/vdb /mnt/minfs
+released superblock resources
+mount: mounting /dev/vdb on /mnt/minfs failed: Not a directory
+root@qemux86:~/skels/filesystems/minfs/user#
+```

tools/labs/skels/filesystems/Lab09.md

@@ -0,0 +1,44 @@
+# Laborator 9
+
+## myfs
+
+### Exercitiul 1
+Am identificat versiunea de kernel de pe masina pentru a gasi versiunea corecta a `ramfs` pe care am folosit-o ca model.
+
+```
+root@qemux86:~# cat /proc/version
+Linux version 5.10.14+
+```
+
+Am completat structura `struct inode_operations` cu operatii specifice inode-ului de tip director: `mknod`, `create` si `mkdir`; aceste functii au fost apoi implementate dupa modelul din `ramfs`. Pentru celelalte functii am folosit varianta generica din VFS.
+
+## Exercitiul 2
+Completand structura struct `file_operations` am adaugat operatiile specifice lucrului cu structura `file` asociata inode-ului folosind tot implementarile generice din VFS. Am adaugat in structura `inode_operations` operatiile pentru manipulare inode-ului si structura `address_space_operations`. Dupa initializare am asignat structurile completate anterior campurilor potrivite din structura de inode.
+
+Am testat corectitudinea implementarii astfel:
+```
+root@qemux86:~/skels/filesystems/myfs# insmod myfs.ko
+myfs: loading out-of-tree module taints kernel.
+root@qemux86:~/skels/filesystems/myfs# mkdir -p /mnt/myfs
+root@qemux86:~/skels/filesystems/myfs# mount -t myfs none /mnt/myfs
+root inode has 2 link(s)
+root@qemux86:~/skels/filesystems/myfs# touch /mnt/myfs/peanuts.txt
+mknod begin
+mknod end
+root@qemux86:~/skels/filesystems/myfs# mkdir -p /mnt/myfs/mountain/forest
+mknod begin
+mknod end
+mknod begin
+mknod end
+root@qemux86:~/skels/filesystems/myfs# touch /mnt/myfs/mountain/forest/tree.txt
+mknod begin
+mknod end
+root@qemux86:~/skels/filesystems/myfs# rm /mnt/myfs/mountain/forest/tree.txt
+root@qemux86:~/skels/filesystems/myfs# rmdir /mnt/myfs/mountain/forest
+root@qemux86:~/skels/filesystems/myfs# echo "chocolate" > /mnt/myfs/peanuts.txt
+root@qemux86:~/skels/filesystems/myfs# cat /mnt/myfs/peanuts.txt
+chocolate
+root@qemux86:~/skels/filesystems/myfs# cat /mnt/myfs/peanuts.txt
+```
+
+## minfs

tools/labs/skels/filesystems/minfs/kernel/Kbuild

@@ -0,0 +1,3 @@
+EXTRA_CFLAGS = -Wall -g -Wno-unused
+
+obj-m = minfs.o