[linux-2.6-block.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 */
		inode->i_nlink = 0;
		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_destroy_inode(struct inode *inode)
{
	struct logfs_inode *li = logfs_inode(inode);

	BUG_ON(li->li_block);
	list_del(&li->li_freeing_list);
	kmem_cache_free(logfs_inode_cache, li);
}

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;
	inode->i_nlink	= 1;
	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.
 */
struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino)
{
	struct inode *inode;

	inode = logfs_alloc_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	inode->i_mode = S_IFREG;
	inode->i_ino = ino;
	inode->i_sb = sb;

	/* This is a blatant copy of alloc_inode code.  We'd need alloc_inode
	 * to be nonstatic, alas. */
	{
		struct address_space * const mapping = &inode->i_data;

		mapping->a_ops = &logfs_reg_aops;
		mapping->host = inode;
		mapping->flags = 0;
		mapping_set_gfp_mask(mapping, GFP_NOFS);
		mapping->assoc_mapping = NULL;
		mapping->backing_dev_info = &default_backing_dev_info;
		inode->i_mapping = mapping;
		inode->i_nlink = 1;
	}

	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) {
		destroy_meta_inode(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;
}

void destroy_meta_inode(struct inode *inode)
{
	if (inode) {
		if (inode->i_data.nrpages)
			truncate_inode_pages(&inode->i_data, 0);
		logfs_clear_inode(inode);
		kmem_cache_free(logfs_inode_cache, logfs_inode(inode));
	}
}

/* called with inode_lock held */
static void 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);
	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->i_uid = current_fsuid();
	inode->i_gid = current_fsgid();
	if (dir->i_mode & S_ISGID) {
		inode->i_gid = dir->i_gid;
		if (S_ISDIR(mode))
			inode->i_mode |= S_ISGID;
	}

	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;
}

const struct super_operations logfs_super_operations = {
	.alloc_inode	= logfs_alloc_inode,
	.clear_inode	= logfs_clear_inode,
	.delete_inode	= logfs_delete_inode,
	.destroy_inode	= logfs_destroy_inode,
	.drop_inode	= logfs_drop_inode,
	.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 */
96	inode->i_nlink = 0;
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
144	static void __logfs_destroy_inode(struct inode *inode)
145	{
146	struct logfs_inode *li = logfs_inode(inode);
147
148	BUG_ON(li->li_block);
149	list_del(&li->li_freeing_list);
150	kmem_cache_free(logfs_inode_cache, li);
151	}
152
153	static void logfs_destroy_inode(struct inode *inode)
154	{
155	struct logfs_inode *li = logfs_inode(inode);
156
157	BUG_ON(list_empty(&li->li_freeing_list));
158	spin_lock(&logfs_inode_lock);
159	li->li_refcount--;
160	if (li->li_refcount == 0)
161	__logfs_destroy_inode(inode);
162	spin_unlock(&logfs_inode_lock);
163	}
164
165	void logfs_safe_iput(struct inode *inode, int is_cached)
166	{
167	if (inode->i_ino == LOGFS_INO_MASTER)
168	return;
169	if (inode->i_ino == LOGFS_INO_SEGFILE)
170	return;
171
172	if (is_cached) {
173	logfs_destroy_inode(inode);
174	return;
175	}
176
177	iput(inode);
178	}
179
180	static void logfs_init_inode(struct super_block sb, struct inode inode)
181	{
182	struct logfs_inode *li = logfs_inode(inode);
183	int i;
184
185	li->li_flags = 0;
186	li->li_height = 0;
187	li->li_used_bytes = 0;
188	li->li_block = NULL;
189	inode->i_uid = 0;
190	inode->i_gid = 0;
191	inode->i_size = 0;
192	inode->i_blocks = 0;
193	inode->i_ctime = CURRENT_TIME;
194	inode->i_mtime = CURRENT_TIME;
195	inode->i_nlink = 1;
24797535	196	li->li_refcount = 1;
5db53f3e JE	197	INIT_LIST_HEAD(&li->li_freeing_list);
	198
	199	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
	200	li->li_data[i] = 0;
	201
	202	return;
	203	}
	204
	205	static struct inode logfs_alloc_inode(struct super_block sb)
	206	{
	207	struct logfs_inode *li;
	208
	209	li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS);
	210	if (!li)
	211	return NULL;
	212	logfs_init_inode(sb, &li->vfs_inode);
	213	return &li->vfs_inode;
	214	}
	215
	216	/*
	217	* In logfs inodes are written to an inode file. The inode file, like any
	218	* other file, is managed with a inode. The inode file's inode, aka master
	219	* inode, requires special handling in several respects. First, it cannot be
	220	* written to the inode file, so it is stored in the journal instead.
	221	*
	222	* Secondly, this inode cannot be written back and destroyed before all other
	223	* inodes have been written. The ordering is important. Linux' VFS is happily
	224	* unaware of the ordering constraint and would ordinarily destroy the master
	225	* inode at umount time while other inodes are still in use and dirty. Not
	226	* good.
	227	*
	228	* So logfs makes sure the master inode is not written until all other inodes
	229	* have been destroyed. Sadly, this method has another side-effect. The VFS
	230	* will notice one remaining inode and print a frightening warning message.
	231	* Worse, it is impossible to judge whether such a warning was caused by the
	232	* master inode or any other inodes have leaked as well.
	233	*
	234	* Our attempt of solving this is with logfs_new_meta_inode() below. Its
	235	* purpose is to create a new inode that will not trigger the warning if such
	236	* an inode is still in use. An ugly hack, no doubt. Suggections for
	237	* improvement are welcome.
	238	*/
	239	struct inode logfs_new_meta_inode(struct super_block sb, u64 ino)
	240	{
	241	struct inode *inode;
	242
	243	inode = logfs_alloc_inode(sb);
	244	if (!inode)
	245	return ERR_PTR(-ENOMEM);
	246
	247	inode->i_mode = S_IFREG;
	248	inode->i_ino = ino;
	249	inode->i_sb = sb;
	250
	251	/* This is a blatant copy of alloc_inode code. We'd need alloc_inode
	252	* to be nonstatic, alas. */
	253	{
	254	struct address_space * const mapping = &inode->i_data;
	255
	256	mapping->a_ops = &logfs_reg_aops;
	257	mapping->host = inode;
	258	mapping->flags = 0;
	259	mapping_set_gfp_mask(mapping, GFP_NOFS);
	260	mapping->assoc_mapping = NULL;
261	mapping->backing_dev_info = &default_backing_dev_info;
262	inode->i_mapping = mapping;
263	inode->i_nlink = 1;
264	}
265
266	return inode;
267	}
268
269	struct inode logfs_read_meta_inode(struct super_block sb, u64 ino)
270	{
271	struct inode *inode;
272	int err;
273
274	inode = logfs_new_meta_inode(sb, ino);
275	if (IS_ERR(inode))
276	return inode;
277
278	err = logfs_read_inode(inode);
279	if (err) {
280	destroy_meta_inode(inode);
281	return ERR_PTR(err);
282	}
283	logfs_inode_setops(inode);
284	return inode;
285	}
286
66b89159	287	static int logfs_write_inode(struct inode inode, struct writeback_control wbc)
5db53f3e JE	288	{
	289	int ret;
	290	long flags = WF_LOCK;
	291
	292	/* Can only happen if creat() failed. Safe to skip. */
	293	if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN)
	294	return 0;
	295
	296	ret = __logfs_write_inode(inode, flags);
	297	LOGFS_BUG_ON(ret, inode->i_sb);
	298	return ret;
	299	}
	300
	301	void destroy_meta_inode(struct inode *inode)
	302	{
	303	if (inode) {
	304	if (inode->i_data.nrpages)
	305	truncate_inode_pages(&inode->i_data, 0);
	306	logfs_clear_inode(inode);
	307	kmem_cache_free(logfs_inode_cache, logfs_inode(inode));
	308	}
	309	}
	310
	311	/* called with inode_lock held */
	312	static void logfs_drop_inode(struct inode *inode)
	313	{
	314	struct logfs_super *super = logfs_super(inode->i_sb);
	315	struct logfs_inode *li = logfs_inode(inode);
	316
	317	spin_lock(&logfs_inode_lock);
	318	list_move(&li->li_freeing_list, &super->s_freeing_list);
	319	spin_unlock(&logfs_inode_lock);
	320	generic_drop_inode(inode);
	321	}
	322
	323	static void logfs_set_ino_generation(struct super_block *sb,
	324	struct inode *inode)
	325	{
	326	struct logfs_super *super = logfs_super(sb);
	327	u64 ino;
	328
	329	mutex_lock(&super->s_journal_mutex);
ccc0197b	330	ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino + 1);
5db53f3e JE	331	super->s_last_ino = ino;
	332	super->s_inos_till_wrap--;
	333	if (super->s_inos_till_wrap < 0) {
	334	super->s_last_ino = LOGFS_RESERVED_INOS;
	335	super->s_generation++;
	336	super->s_inos_till_wrap = INOS_PER_WRAP;
	337	}
	338	inode->i_ino = ino;
	339	inode->i_generation = super->s_generation;
	340	mutex_unlock(&super->s_journal_mutex);
	341	}
	342
	343	struct inode logfs_new_inode(struct inode dir, int mode)
	344	{
	345	struct super_block *sb = dir->i_sb;
	346	struct inode *inode;
	347
	348	inode = new_inode(sb);
	349	if (!inode)
	350	return ERR_PTR(-ENOMEM);
	351
	352	logfs_init_inode(sb, inode);
	353
	354	/* inherit parent flags */
	355	logfs_inode(inode)->li_flags \|=
	356	logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED;
	357
	358	inode->i_mode = mode;
	359	logfs_set_ino_generation(sb, inode);
	360
	361	inode->i_uid = current_fsuid();
	362	inode->i_gid = current_fsgid();
	363	if (dir->i_mode & S_ISGID) {
	364	inode->i_gid = dir->i_gid;
	365	if (S_ISDIR(mode))
	366	inode->i_mode \|= S_ISGID;
	367	}
	368
	369	logfs_inode_setops(inode);
	370	insert_inode_hash(inode);
	371
	372	return inode;
	373	}
	374
	375	static void logfs_init_once(void *_li)
	376	{
	377	struct logfs_inode *li = _li;
	378	int i;
	379
	380	li->li_flags = 0;
	381	li->li_used_bytes = 0;
	382	li->li_refcount = 1;
	383	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
	384	li->li_data[i] = 0;
	385	inode_init_once(&li->vfs_inode);
	386	}
	387
	388	static int logfs_sync_fs(struct super_block *sb, int wait)
	389	{
c0c79c31	390	logfs_write_anchor(sb);
5db53f3e JE	391	return 0;
	392	}
	393
	394	const struct super_operations logfs_super_operations = {
	395	.alloc_inode = logfs_alloc_inode,
	396	.clear_inode = logfs_clear_inode,
	397	.delete_inode = logfs_delete_inode,
	398	.destroy_inode = logfs_destroy_inode,
	399	.drop_inode = logfs_drop_inode,
	400	.write_inode = logfs_write_inode,
	401	.statfs = logfs_statfs,
	402	.sync_fs = logfs_sync_fs,
	403	};
	404
	405	int logfs_init_inode_cache(void)
	406	{
	407	logfs_inode_cache = kmem_cache_create("logfs_inode_cache",
	408	sizeof(struct logfs_inode), 0, SLAB_RECLAIM_ACCOUNT,
	409	logfs_init_once);
	410	if (!logfs_inode_cache)
	411	return -ENOMEM;
	412	return 0;
	413	}
	414
	415	void logfs_destroy_inode_cache(void)
	416	{
	417	kmem_cache_destroy(logfs_inode_cache);
	418	}