cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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orphan.c (18911B)


      1/*
      2 * Ext4 orphan inode handling
      3 */
      4#include <linux/fs.h>
      5#include <linux/quotaops.h>
      6#include <linux/buffer_head.h>
      7
      8#include "ext4.h"
      9#include "ext4_jbd2.h"
     10
     11static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
     12{
     13	int i, j, start;
     14	struct ext4_orphan_info *oi = &EXT4_SB(inode->i_sb)->s_orphan_info;
     15	int ret = 0;
     16	bool found = false;
     17	__le32 *bdata;
     18	int inodes_per_ob = ext4_inodes_per_orphan_block(inode->i_sb);
     19	int looped = 0;
     20
     21	/*
     22	 * Find block with free orphan entry. Use CPU number for a naive hash
     23	 * for a search start in the orphan file
     24	 */
     25	start = raw_smp_processor_id()*13 % oi->of_blocks;
     26	i = start;
     27	do {
     28		if (atomic_dec_if_positive(&oi->of_binfo[i].ob_free_entries)
     29		    >= 0) {
     30			found = true;
     31			break;
     32		}
     33		if (++i >= oi->of_blocks)
     34			i = 0;
     35	} while (i != start);
     36
     37	if (!found) {
     38		/*
     39		 * For now we don't grow or shrink orphan file. We just use
     40		 * whatever was allocated at mke2fs time. The additional
     41		 * credits we would have to reserve for each orphan inode
     42		 * operation just don't seem worth it.
     43		 */
     44		return -ENOSPC;
     45	}
     46
     47	ret = ext4_journal_get_write_access(handle, inode->i_sb,
     48				oi->of_binfo[i].ob_bh, EXT4_JTR_ORPHAN_FILE);
     49	if (ret) {
     50		atomic_inc(&oi->of_binfo[i].ob_free_entries);
     51		return ret;
     52	}
     53
     54	bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
     55	/* Find empty slot in a block */
     56	j = 0;
     57	do {
     58		if (looped) {
     59			/*
     60			 * Did we walk through the block several times without
     61			 * finding free entry? It is theoretically possible
     62			 * if entries get constantly allocated and freed or
     63			 * if the block is corrupted. Avoid indefinite looping
     64			 * and bail. We'll use orphan list instead.
     65			 */
     66			if (looped > 3) {
     67				atomic_inc(&oi->of_binfo[i].ob_free_entries);
     68				return -ENOSPC;
     69			}
     70			cond_resched();
     71		}
     72		while (bdata[j]) {
     73			if (++j >= inodes_per_ob) {
     74				j = 0;
     75				looped++;
     76			}
     77		}
     78	} while (cmpxchg(&bdata[j], (__le32)0, cpu_to_le32(inode->i_ino)) !=
     79		 (__le32)0);
     80
     81	EXT4_I(inode)->i_orphan_idx = i * inodes_per_ob + j;
     82	ext4_set_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
     83
     84	return ext4_handle_dirty_metadata(handle, NULL, oi->of_binfo[i].ob_bh);
     85}
     86
     87/*
     88 * ext4_orphan_add() links an unlinked or truncated inode into a list of
     89 * such inodes, starting at the superblock, in case we crash before the
     90 * file is closed/deleted, or in case the inode truncate spans multiple
     91 * transactions and the last transaction is not recovered after a crash.
     92 *
     93 * At filesystem recovery time, we walk this list deleting unlinked
     94 * inodes and truncating linked inodes in ext4_orphan_cleanup().
     95 *
     96 * Orphan list manipulation functions must be called under i_rwsem unless
     97 * we are just creating the inode or deleting it.
     98 */
     99int ext4_orphan_add(handle_t *handle, struct inode *inode)
    100{
    101	struct super_block *sb = inode->i_sb;
    102	struct ext4_sb_info *sbi = EXT4_SB(sb);
    103	struct ext4_iloc iloc;
    104	int err = 0, rc;
    105	bool dirty = false;
    106
    107	if (!sbi->s_journal || is_bad_inode(inode))
    108		return 0;
    109
    110	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
    111		     !inode_is_locked(inode));
    112	/*
    113	 * Inode orphaned in orphan file or in orphan list?
    114	 */
    115	if (ext4_test_inode_state(inode, EXT4_STATE_ORPHAN_FILE) ||
    116	    !list_empty(&EXT4_I(inode)->i_orphan))
    117		return 0;
    118
    119	/*
    120	 * Orphan handling is only valid for files with data blocks
    121	 * being truncated, or files being unlinked. Note that we either
    122	 * hold i_rwsem, or the inode can not be referenced from outside,
    123	 * so i_nlink should not be bumped due to race
    124	 */
    125	ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
    126		  S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
    127
    128	if (sbi->s_orphan_info.of_blocks) {
    129		err = ext4_orphan_file_add(handle, inode);
    130		/*
    131		 * Fallback to normal orphan list of orphan file is
    132		 * out of space
    133		 */
    134		if (err != -ENOSPC)
    135			return err;
    136	}
    137
    138	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
    139	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
    140					    EXT4_JTR_NONE);
    141	if (err)
    142		goto out;
    143
    144	err = ext4_reserve_inode_write(handle, inode, &iloc);
    145	if (err)
    146		goto out;
    147
    148	mutex_lock(&sbi->s_orphan_lock);
    149	/*
    150	 * Due to previous errors inode may be already a part of on-disk
    151	 * orphan list. If so skip on-disk list modification.
    152	 */
    153	if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
    154	    (le32_to_cpu(sbi->s_es->s_inodes_count))) {
    155		/* Insert this inode at the head of the on-disk orphan list */
    156		NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
    157		lock_buffer(sbi->s_sbh);
    158		sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
    159		ext4_superblock_csum_set(sb);
    160		unlock_buffer(sbi->s_sbh);
    161		dirty = true;
    162	}
    163	list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
    164	mutex_unlock(&sbi->s_orphan_lock);
    165
    166	if (dirty) {
    167		err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
    168		rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
    169		if (!err)
    170			err = rc;
    171		if (err) {
    172			/*
    173			 * We have to remove inode from in-memory list if
    174			 * addition to on disk orphan list failed. Stray orphan
    175			 * list entries can cause panics at unmount time.
    176			 */
    177			mutex_lock(&sbi->s_orphan_lock);
    178			list_del_init(&EXT4_I(inode)->i_orphan);
    179			mutex_unlock(&sbi->s_orphan_lock);
    180		}
    181	} else
    182		brelse(iloc.bh);
    183
    184	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
    185	jbd_debug(4, "orphan inode %lu will point to %d\n",
    186			inode->i_ino, NEXT_ORPHAN(inode));
    187out:
    188	ext4_std_error(sb, err);
    189	return err;
    190}
    191
    192static int ext4_orphan_file_del(handle_t *handle, struct inode *inode)
    193{
    194	struct ext4_orphan_info *oi = &EXT4_SB(inode->i_sb)->s_orphan_info;
    195	__le32 *bdata;
    196	int blk, off;
    197	int inodes_per_ob = ext4_inodes_per_orphan_block(inode->i_sb);
    198	int ret = 0;
    199
    200	if (!handle)
    201		goto out;
    202	blk = EXT4_I(inode)->i_orphan_idx / inodes_per_ob;
    203	off = EXT4_I(inode)->i_orphan_idx % inodes_per_ob;
    204	if (WARN_ON_ONCE(blk >= oi->of_blocks))
    205		goto out;
    206
    207	ret = ext4_journal_get_write_access(handle, inode->i_sb,
    208				oi->of_binfo[blk].ob_bh, EXT4_JTR_ORPHAN_FILE);
    209	if (ret)
    210		goto out;
    211
    212	bdata = (__le32 *)(oi->of_binfo[blk].ob_bh->b_data);
    213	bdata[off] = 0;
    214	atomic_inc(&oi->of_binfo[blk].ob_free_entries);
    215	ret = ext4_handle_dirty_metadata(handle, NULL, oi->of_binfo[blk].ob_bh);
    216out:
    217	ext4_clear_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
    218	INIT_LIST_HEAD(&EXT4_I(inode)->i_orphan);
    219
    220	return ret;
    221}
    222
    223/*
    224 * ext4_orphan_del() removes an unlinked or truncated inode from the list
    225 * of such inodes stored on disk, because it is finally being cleaned up.
    226 */
    227int ext4_orphan_del(handle_t *handle, struct inode *inode)
    228{
    229	struct list_head *prev;
    230	struct ext4_inode_info *ei = EXT4_I(inode);
    231	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
    232	__u32 ino_next;
    233	struct ext4_iloc iloc;
    234	int err = 0;
    235
    236	if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
    237		return 0;
    238
    239	WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
    240		     !inode_is_locked(inode));
    241	if (ext4_test_inode_state(inode, EXT4_STATE_ORPHAN_FILE))
    242		return ext4_orphan_file_del(handle, inode);
    243
    244	/* Do this quick check before taking global s_orphan_lock. */
    245	if (list_empty(&ei->i_orphan))
    246		return 0;
    247
    248	if (handle) {
    249		/* Grab inode buffer early before taking global s_orphan_lock */
    250		err = ext4_reserve_inode_write(handle, inode, &iloc);
    251	}
    252
    253	mutex_lock(&sbi->s_orphan_lock);
    254	jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
    255
    256	prev = ei->i_orphan.prev;
    257	list_del_init(&ei->i_orphan);
    258
    259	/* If we're on an error path, we may not have a valid
    260	 * transaction handle with which to update the orphan list on
    261	 * disk, but we still need to remove the inode from the linked
    262	 * list in memory. */
    263	if (!handle || err) {
    264		mutex_unlock(&sbi->s_orphan_lock);
    265		goto out_err;
    266	}
    267
    268	ino_next = NEXT_ORPHAN(inode);
    269	if (prev == &sbi->s_orphan) {
    270		jbd_debug(4, "superblock will point to %u\n", ino_next);
    271		BUFFER_TRACE(sbi->s_sbh, "get_write_access");
    272		err = ext4_journal_get_write_access(handle, inode->i_sb,
    273						    sbi->s_sbh, EXT4_JTR_NONE);
    274		if (err) {
    275			mutex_unlock(&sbi->s_orphan_lock);
    276			goto out_brelse;
    277		}
    278		lock_buffer(sbi->s_sbh);
    279		sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
    280		ext4_superblock_csum_set(inode->i_sb);
    281		unlock_buffer(sbi->s_sbh);
    282		mutex_unlock(&sbi->s_orphan_lock);
    283		err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
    284	} else {
    285		struct ext4_iloc iloc2;
    286		struct inode *i_prev =
    287			&list_entry(prev, struct ext4_inode_info, i_orphan)->vfs_inode;
    288
    289		jbd_debug(4, "orphan inode %lu will point to %u\n",
    290			  i_prev->i_ino, ino_next);
    291		err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
    292		if (err) {
    293			mutex_unlock(&sbi->s_orphan_lock);
    294			goto out_brelse;
    295		}
    296		NEXT_ORPHAN(i_prev) = ino_next;
    297		err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
    298		mutex_unlock(&sbi->s_orphan_lock);
    299	}
    300	if (err)
    301		goto out_brelse;
    302	NEXT_ORPHAN(inode) = 0;
    303	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
    304out_err:
    305	ext4_std_error(inode->i_sb, err);
    306	return err;
    307
    308out_brelse:
    309	brelse(iloc.bh);
    310	goto out_err;
    311}
    312
    313#ifdef CONFIG_QUOTA
    314static int ext4_quota_on_mount(struct super_block *sb, int type)
    315{
    316	return dquot_quota_on_mount(sb,
    317		rcu_dereference_protected(EXT4_SB(sb)->s_qf_names[type],
    318					  lockdep_is_held(&sb->s_umount)),
    319		EXT4_SB(sb)->s_jquota_fmt, type);
    320}
    321#endif
    322
    323static void ext4_process_orphan(struct inode *inode,
    324				int *nr_truncates, int *nr_orphans)
    325{
    326	struct super_block *sb = inode->i_sb;
    327	int ret;
    328
    329	dquot_initialize(inode);
    330	if (inode->i_nlink) {
    331		if (test_opt(sb, DEBUG))
    332			ext4_msg(sb, KERN_DEBUG,
    333				"%s: truncating inode %lu to %lld bytes",
    334				__func__, inode->i_ino, inode->i_size);
    335		jbd_debug(2, "truncating inode %lu to %lld bytes\n",
    336			  inode->i_ino, inode->i_size);
    337		inode_lock(inode);
    338		truncate_inode_pages(inode->i_mapping, inode->i_size);
    339		ret = ext4_truncate(inode);
    340		if (ret) {
    341			/*
    342			 * We need to clean up the in-core orphan list
    343			 * manually if ext4_truncate() failed to get a
    344			 * transaction handle.
    345			 */
    346			ext4_orphan_del(NULL, inode);
    347			ext4_std_error(inode->i_sb, ret);
    348		}
    349		inode_unlock(inode);
    350		(*nr_truncates)++;
    351	} else {
    352		if (test_opt(sb, DEBUG))
    353			ext4_msg(sb, KERN_DEBUG,
    354				"%s: deleting unreferenced inode %lu",
    355				__func__, inode->i_ino);
    356		jbd_debug(2, "deleting unreferenced inode %lu\n",
    357			  inode->i_ino);
    358		(*nr_orphans)++;
    359	}
    360	iput(inode);  /* The delete magic happens here! */
    361}
    362
    363/* ext4_orphan_cleanup() walks a singly-linked list of inodes (starting at
    364 * the superblock) which were deleted from all directories, but held open by
    365 * a process at the time of a crash.  We walk the list and try to delete these
    366 * inodes at recovery time (only with a read-write filesystem).
    367 *
    368 * In order to keep the orphan inode chain consistent during traversal (in
    369 * case of crash during recovery), we link each inode into the superblock
    370 * orphan list_head and handle it the same way as an inode deletion during
    371 * normal operation (which journals the operations for us).
    372 *
    373 * We only do an iget() and an iput() on each inode, which is very safe if we
    374 * accidentally point at an in-use or already deleted inode.  The worst that
    375 * can happen in this case is that we get a "bit already cleared" message from
    376 * ext4_free_inode().  The only reason we would point at a wrong inode is if
    377 * e2fsck was run on this filesystem, and it must have already done the orphan
    378 * inode cleanup for us, so we can safely abort without any further action.
    379 */
    380void ext4_orphan_cleanup(struct super_block *sb, struct ext4_super_block *es)
    381{
    382	unsigned int s_flags = sb->s_flags;
    383	int nr_orphans = 0, nr_truncates = 0;
    384	struct inode *inode;
    385	int i, j;
    386#ifdef CONFIG_QUOTA
    387	int quota_update = 0;
    388#endif
    389	__le32 *bdata;
    390	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    391	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
    392
    393	if (!es->s_last_orphan && !oi->of_blocks) {
    394		jbd_debug(4, "no orphan inodes to clean up\n");
    395		return;
    396	}
    397
    398	if (bdev_read_only(sb->s_bdev)) {
    399		ext4_msg(sb, KERN_ERR, "write access "
    400			"unavailable, skipping orphan cleanup");
    401		return;
    402	}
    403
    404	/* Check if feature set would not allow a r/w mount */
    405	if (!ext4_feature_set_ok(sb, 0)) {
    406		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
    407			 "unknown ROCOMPAT features");
    408		return;
    409	}
    410
    411	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
    412		/* don't clear list on RO mount w/ errors */
    413		if (es->s_last_orphan && !(s_flags & SB_RDONLY)) {
    414			ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
    415				  "clearing orphan list.\n");
    416			es->s_last_orphan = 0;
    417		}
    418		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
    419		return;
    420	}
    421
    422	if (s_flags & SB_RDONLY) {
    423		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
    424		sb->s_flags &= ~SB_RDONLY;
    425	}
    426#ifdef CONFIG_QUOTA
    427	/*
    428	 * Turn on quotas which were not enabled for read-only mounts if
    429	 * filesystem has quota feature, so that they are updated correctly.
    430	 */
    431	if (ext4_has_feature_quota(sb) && (s_flags & SB_RDONLY)) {
    432		int ret = ext4_enable_quotas(sb);
    433
    434		if (!ret)
    435			quota_update = 1;
    436		else
    437			ext4_msg(sb, KERN_ERR,
    438				"Cannot turn on quotas: error %d", ret);
    439	}
    440
    441	/* Turn on journaled quotas used for old sytle */
    442	for (i = 0; i < EXT4_MAXQUOTAS; i++) {
    443		if (EXT4_SB(sb)->s_qf_names[i]) {
    444			int ret = ext4_quota_on_mount(sb, i);
    445
    446			if (!ret)
    447				quota_update = 1;
    448			else
    449				ext4_msg(sb, KERN_ERR,
    450					"Cannot turn on journaled "
    451					"quota: type %d: error %d", i, ret);
    452		}
    453	}
    454#endif
    455
    456	while (es->s_last_orphan) {
    457		/*
    458		 * We may have encountered an error during cleanup; if
    459		 * so, skip the rest.
    460		 */
    461		if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
    462			jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
    463			es->s_last_orphan = 0;
    464			break;
    465		}
    466
    467		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
    468		if (IS_ERR(inode)) {
    469			es->s_last_orphan = 0;
    470			break;
    471		}
    472
    473		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
    474		ext4_process_orphan(inode, &nr_truncates, &nr_orphans);
    475	}
    476
    477	for (i = 0; i < oi->of_blocks; i++) {
    478		bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
    479		for (j = 0; j < inodes_per_ob; j++) {
    480			if (!bdata[j])
    481				continue;
    482			inode = ext4_orphan_get(sb, le32_to_cpu(bdata[j]));
    483			if (IS_ERR(inode))
    484				continue;
    485			ext4_set_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
    486			EXT4_I(inode)->i_orphan_idx = i * inodes_per_ob + j;
    487			ext4_process_orphan(inode, &nr_truncates, &nr_orphans);
    488		}
    489	}
    490
    491#define PLURAL(x) (x), ((x) == 1) ? "" : "s"
    492
    493	if (nr_orphans)
    494		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
    495		       PLURAL(nr_orphans));
    496	if (nr_truncates)
    497		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
    498		       PLURAL(nr_truncates));
    499#ifdef CONFIG_QUOTA
    500	/* Turn off quotas if they were enabled for orphan cleanup */
    501	if (quota_update) {
    502		for (i = 0; i < EXT4_MAXQUOTAS; i++) {
    503			if (sb_dqopt(sb)->files[i])
    504				dquot_quota_off(sb, i);
    505		}
    506	}
    507#endif
    508	sb->s_flags = s_flags; /* Restore SB_RDONLY status */
    509}
    510
    511void ext4_release_orphan_info(struct super_block *sb)
    512{
    513	int i;
    514	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    515
    516	if (!oi->of_blocks)
    517		return;
    518	for (i = 0; i < oi->of_blocks; i++)
    519		brelse(oi->of_binfo[i].ob_bh);
    520	kfree(oi->of_binfo);
    521}
    522
    523static struct ext4_orphan_block_tail *ext4_orphan_block_tail(
    524						struct super_block *sb,
    525						struct buffer_head *bh)
    526{
    527	return (struct ext4_orphan_block_tail *)(bh->b_data + sb->s_blocksize -
    528				sizeof(struct ext4_orphan_block_tail));
    529}
    530
    531static int ext4_orphan_file_block_csum_verify(struct super_block *sb,
    532					      struct buffer_head *bh)
    533{
    534	__u32 calculated;
    535	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
    536	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    537	struct ext4_orphan_block_tail *ot;
    538	__le64 dsk_block_nr = cpu_to_le64(bh->b_blocknr);
    539
    540	if (!ext4_has_metadata_csum(sb))
    541		return 1;
    542
    543	ot = ext4_orphan_block_tail(sb, bh);
    544	calculated = ext4_chksum(EXT4_SB(sb), oi->of_csum_seed,
    545				 (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr));
    546	calculated = ext4_chksum(EXT4_SB(sb), calculated, (__u8 *)bh->b_data,
    547				 inodes_per_ob * sizeof(__u32));
    548	return le32_to_cpu(ot->ob_checksum) == calculated;
    549}
    550
    551/* This gets called only when checksumming is enabled */
    552void ext4_orphan_file_block_trigger(struct jbd2_buffer_trigger_type *triggers,
    553				    struct buffer_head *bh,
    554				    void *data, size_t size)
    555{
    556	struct super_block *sb = EXT4_TRIGGER(triggers)->sb;
    557	__u32 csum;
    558	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
    559	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    560	struct ext4_orphan_block_tail *ot;
    561	__le64 dsk_block_nr = cpu_to_le64(bh->b_blocknr);
    562
    563	csum = ext4_chksum(EXT4_SB(sb), oi->of_csum_seed,
    564			   (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr));
    565	csum = ext4_chksum(EXT4_SB(sb), csum, (__u8 *)data,
    566			   inodes_per_ob * sizeof(__u32));
    567	ot = ext4_orphan_block_tail(sb, bh);
    568	ot->ob_checksum = cpu_to_le32(csum);
    569}
    570
    571int ext4_init_orphan_info(struct super_block *sb)
    572{
    573	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    574	struct inode *inode;
    575	int i, j;
    576	int ret;
    577	int free;
    578	__le32 *bdata;
    579	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
    580	struct ext4_orphan_block_tail *ot;
    581	ino_t orphan_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_orphan_file_inum);
    582
    583	if (!ext4_has_feature_orphan_file(sb))
    584		return 0;
    585
    586	inode = ext4_iget(sb, orphan_ino, EXT4_IGET_SPECIAL);
    587	if (IS_ERR(inode)) {
    588		ext4_msg(sb, KERN_ERR, "get orphan inode failed");
    589		return PTR_ERR(inode);
    590	}
    591	oi->of_blocks = inode->i_size >> sb->s_blocksize_bits;
    592	oi->of_csum_seed = EXT4_I(inode)->i_csum_seed;
    593	oi->of_binfo = kmalloc(oi->of_blocks*sizeof(struct ext4_orphan_block),
    594			       GFP_KERNEL);
    595	if (!oi->of_binfo) {
    596		ret = -ENOMEM;
    597		goto out_put;
    598	}
    599	for (i = 0; i < oi->of_blocks; i++) {
    600		oi->of_binfo[i].ob_bh = ext4_bread(NULL, inode, i, 0);
    601		if (IS_ERR(oi->of_binfo[i].ob_bh)) {
    602			ret = PTR_ERR(oi->of_binfo[i].ob_bh);
    603			goto out_free;
    604		}
    605		if (!oi->of_binfo[i].ob_bh) {
    606			ret = -EIO;
    607			goto out_free;
    608		}
    609		ot = ext4_orphan_block_tail(sb, oi->of_binfo[i].ob_bh);
    610		if (le32_to_cpu(ot->ob_magic) != EXT4_ORPHAN_BLOCK_MAGIC) {
    611			ext4_error(sb, "orphan file block %d: bad magic", i);
    612			ret = -EIO;
    613			goto out_free;
    614		}
    615		if (!ext4_orphan_file_block_csum_verify(sb,
    616						oi->of_binfo[i].ob_bh)) {
    617			ext4_error(sb, "orphan file block %d: bad checksum", i);
    618			ret = -EIO;
    619			goto out_free;
    620		}
    621		bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
    622		free = 0;
    623		for (j = 0; j < inodes_per_ob; j++)
    624			if (bdata[j] == 0)
    625				free++;
    626		atomic_set(&oi->of_binfo[i].ob_free_entries, free);
    627	}
    628	iput(inode);
    629	return 0;
    630out_free:
    631	for (i--; i >= 0; i--)
    632		brelse(oi->of_binfo[i].ob_bh);
    633	kfree(oi->of_binfo);
    634out_put:
    635	iput(inode);
    636	return ret;
    637}
    638
    639int ext4_orphan_file_empty(struct super_block *sb)
    640{
    641	struct ext4_orphan_info *oi = &EXT4_SB(sb)->s_orphan_info;
    642	int i;
    643	int inodes_per_ob = ext4_inodes_per_orphan_block(sb);
    644
    645	if (!ext4_has_feature_orphan_file(sb))
    646		return 1;
    647	for (i = 0; i < oi->of_blocks; i++)
    648		if (atomic_read(&oi->of_binfo[i].ob_free_entries) !=
    649		    inodes_per_ob)
    650			return 0;
    651	return 1;
    652}