[mirror_ubuntu-artful-kernel.git] / fs / logfs / inode.c

/*
 * 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
 * wether 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 = &logfs_symlink_iops;
		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);
	INIT_LIST_HEAD(&inode->i_dentry);
	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_inode(struct inode *inode)
{
	struct logfs_inode *li = logfs_inode(inode);

	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;
	inode->i_uid	= 0;
	inode->i_gid	= 0;
	inode->i_size	= 0;
	inode->i_blocks	= 0;
	inode->i_ctime	= CURRENT_TIME;
	inode->i_mtime	= CURRENT_TIME;
	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, 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, int 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_write_anchor(sb);
	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_master_inode);
	iput(super->s_segfile_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,
			logfs_init_once);
	if (!logfs_inode_cache)
		return -ENOMEM;
	return 0;
}

void logfs_destroy_inode_cache(void)
{
	kmem_cache_destroy(logfs_inode_cache);
}
Commit	Line	Data
5db53f3e JE	1	/*
	2	* fs/logfs/inode.c - inode handling code
	3	*
	4	* As should be obvious for Linux kernel code, license is GPLv2
	5	*
	6	* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
	7	*/
	8	#include "logfs.h"
5a0e3ad6	9	#include <linux/slab.h>
5db53f3e JE	10	#include <linux/writeback.h>
	11	#include <linux/backing-dev.h>
	12
	13	/*
	14	* How soon to reuse old inode numbers? LogFS doesn't store deleted inodes
	15	* on the medium. It therefore also lacks a method to store the previous
	16	* generation number for deleted inodes. Instead a single generation number
	17	* is stored which will be used for new inodes. Being just a 32bit counter,
	18	* this can obvious wrap relatively quickly. So we only reuse inodes if we
	19	* know that a fair number of inodes can be created before we have to increment
	20	* the generation again - effectively adding some bits to the counter.
	21	* But being too aggressive here means we keep a very large and very sparse
	22	* inode file, wasting space on indirect blocks.
	23	* So what is a good value? Beats me. 64k seems moderately bad on both
	24	* fronts, so let's use that for now...
	25	*
	26	* NFS sucks, as everyone already knows.
	27	*/
	28	#define INOS_PER_WRAP (0x10000)
	29
	30	/*
	31	* Logfs' requirement to read inodes for garbage collection makes life a bit
	32	* harder. GC may have to read inodes that are in I_FREEING state, when they
	33	* are being written out - and waiting for GC to make progress, naturally.
	34	*
	35	* So we cannot just call iget() or some variant of it, but first have to check
	36	* wether the inode in question might be in I_FREEING state. Therefore we
	37	* maintain our own per-sb list of "almost deleted" inodes and check against
	38	* that list first. Normally this should be at most 1-2 entries long.
	39	*
	40	* Also, inodes have logfs-specific reference counting on top of what the vfs
	41	* does. When .destroy_inode is called, normally the reference count will drop
	42	* to zero and the inode gets deleted. But if GC accessed the inode, its
	43	* refcount will remain nonzero and final deletion will have to wait.
	44	*
	45	* As a result we have two sets of functions to get/put inodes:
	46	* logfs_safe_iget/logfs_safe_iput - safe to call from GC context
	47	* logfs_iget/iput - normal version
	48	*/
	49	static struct kmem_cache *logfs_inode_cache;
	50
	51	static DEFINE_SPINLOCK(logfs_inode_lock);
	52
	53	static void logfs_inode_setops(struct inode *inode)
	54	{
	55	switch (inode->i_mode & S_IFMT) {
	56	case S_IFDIR:
	57	inode->i_op = &logfs_dir_iops;
	58	inode->i_fop = &logfs_dir_fops;
	59	inode->i_mapping->a_ops = &logfs_reg_aops;
	60	break;
	61	case S_IFREG:
	62	inode->i_op = &logfs_reg_iops;
	63	inode->i_fop = &logfs_reg_fops;
	64	inode->i_mapping->a_ops = &logfs_reg_aops;
	65	break;
	66	case S_IFLNK:
	67	inode->i_op = &logfs_symlink_iops;
	68	inode->i_mapping->a_ops = &logfs_reg_aops;
	69	break;
	70	case S_IFSOCK: /* fall through */
	71	case S_IFBLK: /* fall through */
	72	case S_IFCHR: /* fall through */
	73	case S_IFIFO:
74	init_special_inode(inode, inode->i_mode, inode->i_rdev);
75	break;
76	default:
77	BUG();
78	}
79	}
80
81	static struct inode __logfs_iget(struct super_block sb, ino_t ino)
82	{
83	struct inode *inode = iget_locked(sb, ino);
84	int err;
85
86	if (!inode)
87	return ERR_PTR(-ENOMEM);
88	if (!(inode->i_state & I_NEW))
89	return inode;
90
91	err = logfs_read_inode(inode);
92	if (err \|\| inode->i_nlink == 0) {
93	/* inode->i_nlink == 0 can be true when called from
94	* block validator */
95	/* set i_nlink to 0 to prevent caching */
6d6b77f1	96	clear_nlink(inode);
5db53f3e JE	97	logfs_inode(inode)->li_flags \|= LOGFS_IF_ZOMBIE;
	98	iget_failed(inode);
	99	if (!err)
	100	err = -ENOENT;
	101	return ERR_PTR(err);
	102	}
	103
	104	logfs_inode_setops(inode);
	105	unlock_new_inode(inode);
	106	return inode;
	107	}
	108
	109	struct inode logfs_iget(struct super_block sb, ino_t ino)
	110	{
	111	BUG_ON(ino == LOGFS_INO_MASTER);
	112	BUG_ON(ino == LOGFS_INO_SEGFILE);
	113	return __logfs_iget(sb, ino);
	114	}
	115
	116	/*
	117	* is_cached is set to 1 if we hand out a cached inode, 0 otherwise.
	118	* this allows logfs_iput to do the right thing later
	119	*/
	120	struct inode logfs_safe_iget(struct super_block sb, ino_t ino, int *is_cached)
	121	{
	122	struct logfs_super *super = logfs_super(sb);
	123	struct logfs_inode *li;
	124
	125	if (ino == LOGFS_INO_MASTER)
	126	return super->s_master_inode;
	127	if (ino == LOGFS_INO_SEGFILE)
	128	return super->s_segfile_inode;
	129
	130	spin_lock(&logfs_inode_lock);
	131	list_for_each_entry(li, &super->s_freeing_list, li_freeing_list)
	132	if (li->vfs_inode.i_ino == ino) {
	133	li->li_refcount++;
	134	spin_unlock(&logfs_inode_lock);
	135	*is_cached = 1;
	136	return &li->vfs_inode;
	137	}
	138	spin_unlock(&logfs_inode_lock);
	139
	140	*is_cached = 0;
	141	return __logfs_iget(sb, ino);
	142	}
	143
fa0d7e3d NP	144	static void logfs_i_callback(struct rcu_head *head)
	145	{
	146	struct inode *inode = container_of(head, struct inode, i_rcu);
	147	INIT_LIST_HEAD(&inode->i_dentry);
	148	kmem_cache_free(logfs_inode_cache, logfs_inode(inode));
	149	}
	150
5db53f3e JE	151	static void __logfs_destroy_inode(struct inode *inode)
	152	{
	153	struct logfs_inode *li = logfs_inode(inode);
	154
	155	BUG_ON(li->li_block);
	156	list_del(&li->li_freeing_list);
fa0d7e3d	157	call_rcu(&inode->i_rcu, logfs_i_callback);
5db53f3e JE	158	}
	159
	160	static void logfs_destroy_inode(struct inode *inode)
	161	{
	162	struct logfs_inode *li = logfs_inode(inode);
	163
	164	BUG_ON(list_empty(&li->li_freeing_list));
	165	spin_lock(&logfs_inode_lock);
	166	li->li_refcount--;
	167	if (li->li_refcount == 0)
	168	__logfs_destroy_inode(inode);
	169	spin_unlock(&logfs_inode_lock);
	170	}
	171
	172	void logfs_safe_iput(struct inode *inode, int is_cached)
	173	{
	174	if (inode->i_ino == LOGFS_INO_MASTER)
	175	return;
	176	if (inode->i_ino == LOGFS_INO_SEGFILE)
	177	return;
	178
	179	if (is_cached) {
	180	logfs_destroy_inode(inode);
	181	return;
	182	}
	183
	184	iput(inode);
	185	}
	186
	187	static void logfs_init_inode(struct super_block sb, struct inode inode)
	188	{
	189	struct logfs_inode *li = logfs_inode(inode);
	190	int i;
	191
	192	li->li_flags = 0;
	193	li->li_height = 0;
	194	li->li_used_bytes = 0;
	195	li->li_block = NULL;
	196	inode->i_uid = 0;
	197	inode->i_gid = 0;
	198	inode->i_size = 0;
	199	inode->i_blocks = 0;
	200	inode->i_ctime = CURRENT_TIME;
	201	inode->i_mtime = CURRENT_TIME;
24797535	202	li->li_refcount = 1;
5db53f3e JE	203	INIT_LIST_HEAD(&li->li_freeing_list);
	204
	205	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
	206	li->li_data[i] = 0;
	207
	208	return;
	209	}
	210
	211	static struct inode logfs_alloc_inode(struct super_block sb)
	212	{
	213	struct logfs_inode *li;
	214
	215	li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS);
	216	if (!li)
	217	return NULL;
	218	logfs_init_inode(sb, &li->vfs_inode);
	219	return &li->vfs_inode;
	220	}
	221
	222	/*
	223	* In logfs inodes are written to an inode file. The inode file, like any
	224	* other file, is managed with a inode. The inode file's inode, aka master
	225	* inode, requires special handling in several respects. First, it cannot be
	226	* written to the inode file, so it is stored in the journal instead.
	227	*
	228	* Secondly, this inode cannot be written back and destroyed before all other
	229	* inodes have been written. The ordering is important. Linux' VFS is happily
	230	* unaware of the ordering constraint and would ordinarily destroy the master
	231	* inode at umount time while other inodes are still in use and dirty. Not
	232	* good.
	233	*
	234	* So logfs makes sure the master inode is not written until all other inodes
	235	* have been destroyed. Sadly, this method has another side-effect. The VFS
	236	* will notice one remaining inode and print a frightening warning message.
	237	* Worse, it is impossible to judge whether such a warning was caused by the
	238	* master inode or any other inodes have leaked as well.
	239	*
	240	* Our attempt of solving this is with logfs_new_meta_inode() below. Its
	241	* purpose is to create a new inode that will not trigger the warning if such
	242	* an inode is still in use. An ugly hack, no doubt. Suggections for
	243	* improvement are welcome.
8e22c1a4 AV	244	*
8e22c1a4 AV	245	* AV: that's what ->put_super() is for...
5db53f3e JE	246	*/
	247	struct inode logfs_new_meta_inode(struct super_block sb, u64 ino)
	248	{
	249	struct inode *inode;
	250
8e22c1a4	251	inode = new_inode(sb);
5db53f3e JE	252	if (!inode)
	253	return ERR_PTR(-ENOMEM);
	254
	255	inode->i_mode = S_IFREG;
	256	inode->i_ino = ino;
8e22c1a4 AV	257	inode->i_data.a_ops = &logfs_reg_aops;
8e22c1a4 AV	258	mapping_set_gfp_mask(&inode->i_data, GFP_NOFS);
5db53f3e JE	259
	260	return inode;
	261	}
	262
	263	struct inode logfs_read_meta_inode(struct super_block sb, u64 ino)
	264	{
	265	struct inode *inode;
	266	int err;
	267
	268	inode = logfs_new_meta_inode(sb, ino);
	269	if (IS_ERR(inode))
	270	return inode;
	271
	272	err = logfs_read_inode(inode);
	273	if (err) {
8e22c1a4	274	iput(inode);
5db53f3e JE	275	return ERR_PTR(err);
	276	}
	277	logfs_inode_setops(inode);
	278	return inode;
	279	}
	280
66b89159	281	static int logfs_write_inode(struct inode inode, struct writeback_control wbc)
5db53f3e JE	282	{
	283	int ret;
	284	long flags = WF_LOCK;
	285
	286	/* Can only happen if creat() failed. Safe to skip. */
	287	if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN)
	288	return 0;
	289
	290	ret = __logfs_write_inode(inode, flags);
	291	LOGFS_BUG_ON(ret, inode->i_sb);
	292	return ret;
	293	}
	294
f283c86a	295	/* called with inode->i_lock held */
45321ac5	296	static int logfs_drop_inode(struct inode *inode)
5db53f3e JE	297	{
	298	struct logfs_super *super = logfs_super(inode->i_sb);
	299	struct logfs_inode *li = logfs_inode(inode);
	300
	301	spin_lock(&logfs_inode_lock);
	302	list_move(&li->li_freeing_list, &super->s_freeing_list);
	303	spin_unlock(&logfs_inode_lock);
45321ac5	304	return generic_drop_inode(inode);
5db53f3e JE	305	}
	306
	307	static void logfs_set_ino_generation(struct super_block *sb,
	308	struct inode *inode)
	309	{
	310	struct logfs_super *super = logfs_super(sb);
	311	u64 ino;
	312
	313	mutex_lock(&super->s_journal_mutex);
ccc0197b	314	ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino + 1);
5db53f3e JE	315	super->s_last_ino = ino;
	316	super->s_inos_till_wrap--;
	317	if (super->s_inos_till_wrap < 0) {
	318	super->s_last_ino = LOGFS_RESERVED_INOS;
	319	super->s_generation++;
	320	super->s_inos_till_wrap = INOS_PER_WRAP;
	321	}
	322	inode->i_ino = ino;
	323	inode->i_generation = super->s_generation;
	324	mutex_unlock(&super->s_journal_mutex);
	325	}
	326
	327	struct inode logfs_new_inode(struct inode dir, int mode)
	328	{
	329	struct super_block *sb = dir->i_sb;
	330	struct inode *inode;
	331
	332	inode = new_inode(sb);
	333	if (!inode)
	334	return ERR_PTR(-ENOMEM);
	335
	336	logfs_init_inode(sb, inode);
	337
	338	/* inherit parent flags */
	339	logfs_inode(inode)->li_flags \|=
	340	logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED;
	341
	342	inode->i_mode = mode;
	343	logfs_set_ino_generation(sb, inode);
	344
ab9a79b9	345	inode_init_owner(inode, dir, mode);
5db53f3e JE	346	logfs_inode_setops(inode);
	347	insert_inode_hash(inode);
	348
	349	return inode;
	350	}
	351
	352	static void logfs_init_once(void *_li)
	353	{
	354	struct logfs_inode *li = _li;
	355	int i;
	356
	357	li->li_flags = 0;
	358	li->li_used_bytes = 0;
	359	li->li_refcount = 1;
	360	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
	361	li->li_data[i] = 0;
	362	inode_init_once(&li->vfs_inode);
	363	}
	364
	365	static int logfs_sync_fs(struct super_block *sb, int wait)
	366	{
c0c79c31	367	logfs_write_anchor(sb);
5db53f3e JE	368	return 0;
	369	}
	370
8e22c1a4 AV	371	static void logfs_put_super(struct super_block *sb)
	372	{
	373	struct logfs_super *super = logfs_super(sb);
	374	/* kill the meta-inodes */
	375	iput(super->s_master_inode);
	376	iput(super->s_segfile_inode);
	377	iput(super->s_mapping_inode);
	378	}
	379
5db53f3e JE	380	const struct super_operations logfs_super_operations = {
5db53f3e JE	381	.alloc_inode = logfs_alloc_inode,
5db53f3e	382	.destroy_inode = logfs_destroy_inode,
7da08fd1	383	.evict_inode = logfs_evict_inode,
5db53f3e	384	.drop_inode = logfs_drop_inode,
8e22c1a4	385	.put_super = logfs_put_super,
5db53f3e JE	386	.write_inode = logfs_write_inode,
	387	.statfs = logfs_statfs,
	388	.sync_fs = logfs_sync_fs,
	389	};
	390
	391	int logfs_init_inode_cache(void)
	392	{
	393	logfs_inode_cache = kmem_cache_create("logfs_inode_cache",
	394	sizeof(struct logfs_inode), 0, SLAB_RECLAIM_ACCOUNT,
	395	logfs_init_once);
	396	if (!logfs_inode_cache)
	397	return -ENOMEM;
	398	return 0;
	399	}
	400
	401	void logfs_destroy_inode_cache(void)
	402	{
	403	kmem_cache_destroy(logfs_inode_cache);
	404	}