logfs: remove from tree

Logfs was introduced to the kernel in 2009, and hasn't seen any non
drive-by changes since 2012, while having lots of unsolved issues
including the complete lack of error handling, with more and more
issues popping up without any fixes.

The logfs.org domain has been bouncing from a mail, and the maintainer
on the non-logfs.org domain hasn't repsonded to past queries either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 0 insertions, 428 deletions

diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c
deleted file mode 100644
index f440a1525da8..000000000000
--- a/fs/logfs/inode.c
+++ /dev/null
@@ -1,428 +0,0 @@
-/*
- * fs/logfs/inode.c	- inode handling code
- *
- * As should be obvious for Linux kernel code, license is GPLv2
- *
- * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
- */
-#include "logfs.h"
-#include <linux/slab.h>
-#include <linux/writeback.h>
-#include <linux/backing-dev.h>
-
-/*
- * How soon to reuse old inode numbers?  LogFS doesn't store deleted inodes
- * on the medium.  It therefore also lacks a method to store the previous
- * generation number for deleted inodes.  Instead a single generation number
- * is stored which will be used for new inodes.  Being just a 32bit counter,
- * this can obvious wrap relatively quickly.  So we only reuse inodes if we
- * know that a fair number of inodes can be created before we have to increment
- * the generation again - effectively adding some bits to the counter.
- * But being too aggressive here means we keep a very large and very sparse
- * inode file, wasting space on indirect blocks.
- * So what is a good value?  Beats me.  64k seems moderately bad on both
- * fronts, so let's use that for now...
- *
- * NFS sucks, as everyone already knows.
- */
-#define INOS_PER_WRAP (0x10000)
-
-/*
- * Logfs' requirement to read inodes for garbage collection makes life a bit
- * harder.  GC may have to read inodes that are in I_FREEING state, when they
- * are being written out - and waiting for GC to make progress, naturally.
- *
- * So we cannot just call iget() or some variant of it, but first have to check
- * whether the inode in question might be in I_FREEING state.  Therefore we
- * maintain our own per-sb list of "almost deleted" inodes and check against
- * that list first.  Normally this should be at most 1-2 entries long.
- *
- * Also, inodes have logfs-specific reference counting on top of what the vfs
- * does.  When .destroy_inode is called, normally the reference count will drop
- * to zero and the inode gets deleted.  But if GC accessed the inode, its
- * refcount will remain nonzero and final deletion will have to wait.
- *
- * As a result we have two sets of functions to get/put inodes:
- * logfs_safe_iget/logfs_safe_iput	- safe to call from GC context
- * logfs_iget/iput			- normal version
- */
-static struct kmem_cache *logfs_inode_cache;
-
-static DEFINE_SPINLOCK(logfs_inode_lock);
-
-static void logfs_inode_setops(struct inode *inode)
-{
-	switch (inode->i_mode & S_IFMT) {
-	case S_IFDIR:
-		inode->i_op = &logfs_dir_iops;
-		inode->i_fop = &logfs_dir_fops;
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFREG:
-		inode->i_op = &logfs_reg_iops;
-		inode->i_fop = &logfs_reg_fops;
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFLNK:
-		inode->i_op = &page_symlink_inode_operations;
-		inode_nohighmem(inode);
-		inode->i_mapping->a_ops = &logfs_reg_aops;
-		break;
-	case S_IFSOCK:	/* fall through */
-	case S_IFBLK:	/* fall through */
-	case S_IFCHR:	/* fall through */
-	case S_IFIFO:
-		init_special_inode(inode, inode->i_mode, inode->i_rdev);
-		break;
-	default:
-		BUG();
-	}
-}
-
-static struct inode *__logfs_iget(struct super_block *sb, ino_t ino)
-{
-	struct inode *inode = iget_locked(sb, ino);
-	int err;
-
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-	if (!(inode->i_state & I_NEW))
-		return inode;
-
-	err = logfs_read_inode(inode);
-	if (err || inode->i_nlink == 0) {
-		/* inode->i_nlink == 0 can be true when called from
-		 * block validator */
-		/* set i_nlink to 0 to prevent caching */
-		clear_nlink(inode);
-		logfs_inode(inode)->li_flags |= LOGFS_IF_ZOMBIE;
-		iget_failed(inode);
-		if (!err)
-			err = -ENOENT;
-		return ERR_PTR(err);
-	}
-
-	logfs_inode_setops(inode);
-	unlock_new_inode(inode);
-	return inode;
-}
-
-struct inode *logfs_iget(struct super_block *sb, ino_t ino)
-{
-	BUG_ON(ino == LOGFS_INO_MASTER);
-	BUG_ON(ino == LOGFS_INO_SEGFILE);
-	return __logfs_iget(sb, ino);
-}
-
-/*
- * is_cached is set to 1 if we hand out a cached inode, 0 otherwise.
- * this allows logfs_iput to do the right thing later
- */
-struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *is_cached)
-{
-	struct logfs_super *super = logfs_super(sb);
-	struct logfs_inode *li;
-
-	if (ino == LOGFS_INO_MASTER)
-		return super->s_master_inode;
-	if (ino == LOGFS_INO_SEGFILE)
-		return super->s_segfile_inode;
-
-	spin_lock(&logfs_inode_lock);
-	list_for_each_entry(li, &super->s_freeing_list, li_freeing_list)
-		if (li->vfs_inode.i_ino == ino) {
-			li->li_refcount++;
-			spin_unlock(&logfs_inode_lock);
-			*is_cached = 1;
-			return &li->vfs_inode;
-		}
-	spin_unlock(&logfs_inode_lock);
-
-	*is_cached = 0;
-	return __logfs_iget(sb, ino);
-}
-
-static void logfs_i_callback(struct rcu_head *head)
-{
-	struct inode *inode = container_of(head, struct inode, i_rcu);
-	kmem_cache_free(logfs_inode_cache, logfs_inode(inode));
-}
-
-static void __logfs_destroy_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	BUG_ON(li->li_block);
-	list_del(&li->li_freeing_list);
-	call_rcu(&inode->i_rcu, logfs_i_callback);
-}
-
-static void __logfs_destroy_meta_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	BUG_ON(li->li_block);
-	call_rcu(&inode->i_rcu, logfs_i_callback);
-}
-
-static void logfs_destroy_inode(struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-
-	if (inode->i_ino < LOGFS_RESERVED_INOS) {
-		/*
-		 * The reserved inodes are never destroyed unless we are in
-		 * unmont path.
-		 */
-		__logfs_destroy_meta_inode(inode);
-		return;
-	}
-
-	BUG_ON(list_empty(&li->li_freeing_list));
-	spin_lock(&logfs_inode_lock);
-	li->li_refcount--;
-	if (li->li_refcount == 0)
-		__logfs_destroy_inode(inode);
-	spin_unlock(&logfs_inode_lock);
-}
-
-void logfs_safe_iput(struct inode *inode, int is_cached)
-{
-	if (inode->i_ino == LOGFS_INO_MASTER)
-		return;
-	if (inode->i_ino == LOGFS_INO_SEGFILE)
-		return;
-
-	if (is_cached) {
-		logfs_destroy_inode(inode);
-		return;
-	}
-
-	iput(inode);
-}
-
-static void logfs_init_inode(struct super_block *sb, struct inode *inode)
-{
-	struct logfs_inode *li = logfs_inode(inode);
-	int i;
-
-	li->li_flags	= 0;
-	li->li_height	= 0;
-	li->li_used_bytes = 0;
-	li->li_block	= NULL;
-	i_uid_write(inode, 0);
-	i_gid_write(inode, 0);
-	inode->i_size	= 0;
-	inode->i_blocks	= 0;
-	inode->i_ctime	= current_time(inode);
-	inode->i_mtime	= current_time(inode);
-	li->li_refcount = 1;
-	INIT_LIST_HEAD(&li->li_freeing_list);
-
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		li->li_data[i] = 0;
-
-	return;
-}
-
-static struct inode *logfs_alloc_inode(struct super_block *sb)
-{
-	struct logfs_inode *li;
-
-	li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS);
-	if (!li)
-		return NULL;
-	logfs_init_inode(sb, &li->vfs_inode);
-	return &li->vfs_inode;
-}
-
-/*
- * In logfs inodes are written to an inode file.  The inode file, like any
- * other file, is managed with a inode.  The inode file's inode, aka master
- * inode, requires special handling in several respects.  First, it cannot be
- * written to the inode file, so it is stored in the journal instead.
- *
- * Secondly, this inode cannot be written back and destroyed before all other
- * inodes have been written.  The ordering is important.  Linux' VFS is happily
- * unaware of the ordering constraint and would ordinarily destroy the master
- * inode at umount time while other inodes are still in use and dirty.  Not
- * good.
- *
- * So logfs makes sure the master inode is not written until all other inodes
- * have been destroyed.  Sadly, this method has another side-effect.  The VFS
- * will notice one remaining inode and print a frightening warning message.
- * Worse, it is impossible to judge whether such a warning was caused by the
- * master inode or any other inodes have leaked as well.
- *
- * Our attempt of solving this is with logfs_new_meta_inode() below.  Its
- * purpose is to create a new inode that will not trigger the warning if such
- * an inode is still in use.  An ugly hack, no doubt.  Suggections for
- * improvement are welcome.
- *
- * AV: that's what ->put_super() is for...
- */
-struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino)
-{
-	struct inode *inode;
-
-	inode = new_inode(sb);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-
-	inode->i_mode = S_IFREG;
-	inode->i_ino = ino;
-	inode->i_data.a_ops = &logfs_reg_aops;
-	mapping_set_gfp_mask(&inode->i_data, GFP_NOFS);
-
-	return inode;
-}
-
-struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino)
-{
-	struct inode *inode;
-	int err;
-
-	inode = logfs_new_meta_inode(sb, ino);
-	if (IS_ERR(inode))
-		return inode;
-
-	err = logfs_read_inode(inode);
-	if (err) {
-		iput(inode);
-		return ERR_PTR(err);
-	}
-	logfs_inode_setops(inode);
-	return inode;
-}
-
-static int logfs_write_inode(struct inode *inode, struct writeback_control *wbc)
-{
-	int ret;
-	long flags = WF_LOCK;
-
-	/* Can only happen if creat() failed.  Safe to skip. */
-	if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN)
-		return 0;
-
-	ret = __logfs_write_inode(inode, NULL, flags);
-	LOGFS_BUG_ON(ret, inode->i_sb);
-	return ret;
-}
-
-/* called with inode->i_lock held */
-static int logfs_drop_inode(struct inode *inode)
-{
-	struct logfs_super *super = logfs_super(inode->i_sb);
-	struct logfs_inode *li = logfs_inode(inode);
-
-	spin_lock(&logfs_inode_lock);
-	list_move(&li->li_freeing_list, &super->s_freeing_list);
-	spin_unlock(&logfs_inode_lock);
-	return generic_drop_inode(inode);
-}
-
-static void logfs_set_ino_generation(struct super_block *sb,
-		struct inode *inode)
-{
-	struct logfs_super *super = logfs_super(sb);
-	u64 ino;
-
-	mutex_lock(&super->s_journal_mutex);
-	ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino + 1);
-	super->s_last_ino = ino;
-	super->s_inos_till_wrap--;
-	if (super->s_inos_till_wrap < 0) {
-		super->s_last_ino = LOGFS_RESERVED_INOS;
-		super->s_generation++;
-		super->s_inos_till_wrap = INOS_PER_WRAP;
-	}
-	inode->i_ino = ino;
-	inode->i_generation = super->s_generation;
-	mutex_unlock(&super->s_journal_mutex);
-}
-
-struct inode *logfs_new_inode(struct inode *dir, umode_t mode)
-{
-	struct super_block *sb = dir->i_sb;
-	struct inode *inode;
-
-	inode = new_inode(sb);
-	if (!inode)
-		return ERR_PTR(-ENOMEM);
-
-	logfs_init_inode(sb, inode);
-
-	/* inherit parent flags */
-	logfs_inode(inode)->li_flags |=
-		logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED;
-
-	inode->i_mode = mode;
-	logfs_set_ino_generation(sb, inode);
-
-	inode_init_owner(inode, dir, mode);
-	logfs_inode_setops(inode);
-	insert_inode_hash(inode);
-
-	return inode;
-}
-
-static void logfs_init_once(void *_li)
-{
-	struct logfs_inode *li = _li;
-	int i;
-
-	li->li_flags = 0;
-	li->li_used_bytes = 0;
-	li->li_refcount = 1;
-	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
-		li->li_data[i] = 0;
-	inode_init_once(&li->vfs_inode);
-}
-
-static int logfs_sync_fs(struct super_block *sb, int wait)
-{
-	logfs_get_wblocks(sb, NULL, WF_LOCK);
-	logfs_write_anchor(sb);
-	logfs_put_wblocks(sb, NULL, WF_LOCK);
-	return 0;
-}
-
-static void logfs_put_super(struct super_block *sb)
-{
-	struct logfs_super *super = logfs_super(sb);
-	/* kill the meta-inodes */
-	iput(super->s_segfile_inode);
-	iput(super->s_master_inode);
-	iput(super->s_mapping_inode);
-}
-
-const struct super_operations logfs_super_operations = {
-	.alloc_inode	= logfs_alloc_inode,
-	.destroy_inode	= logfs_destroy_inode,
-	.evict_inode	= logfs_evict_inode,
-	.drop_inode	= logfs_drop_inode,
-	.put_super	= logfs_put_super,
-	.write_inode	= logfs_write_inode,
-	.statfs		= logfs_statfs,
-	.sync_fs	= logfs_sync_fs,
-};
-
-int logfs_init_inode_cache(void)
-{
-	logfs_inode_cache = kmem_cache_create("logfs_inode_cache",
-			sizeof(struct logfs_inode), 0,
-			SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
-			logfs_init_once);
-	if (!logfs_inode_cache)
-		return -ENOMEM;
-	return 0;
-}
-
-void logfs_destroy_inode_cache(void)
-{
-	/*
-	 * Make sure all delayed rcu free inodes are flushed before we
-	 * destroy cache.
-	 */
-	rcu_barrier();
-	kmem_cache_destroy(logfs_inode_cache);
-}