Commit 30a7eb97 authored by Tahsin Erdogan's avatar Tahsin Erdogan Committed by Theodore Ts'o
Browse files

ext4: cleanup transaction restarts during inode deletion 



During inode deletion, the number of journal credits that will be
needed is hard to determine.  For that reason we have journal
extend/restart calls in several places.  Whenever a transaction is
restarted, filesystem must be in a consistent state because there is
no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of
journal extend/restart logic.  It also handles getting jbd2 write
access and dirty metadata calls.  This function is called at every
iteration of handling an ea_inode reference.

Signed-off-by: default avatarTahsin Erdogan <tahsin@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 02749a4c

fs/ext4/inode.c

+17 −49
Original line number Diff line number Diff line
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode) 
	 */

	sb_start_intwrite(inode->i_sb);



	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);

	if (!IS_NOQUOTA(inode))

		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);



	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,

				 ext4_blocks_for_truncate(inode)+extra_credits);

	if (IS_ERR(handle)) {

		ext4_std_error(inode->i_sb, PTR_ERR(handle));

		/*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode) 
		sb_end_intwrite(inode->i_sb);

		goto no_delete;

	}



	if (IS_SYNC(inode))

		ext4_handle_sync(handle);



	/*

	 * Delete xattr inode before deleting the main inode.

	 */

	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);

	if (err) {

		ext4_warning(inode->i_sb,

			     "couldn't delete inode's xattr (err %d)", err);

		goto stop_handle;

	}



	if (!IS_NOQUOTA(inode))

		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);



	if (!ext4_handle_has_enough_credits(handle,

			ext4_blocks_for_truncate(inode) + extra_credits)) {

		err = ext4_journal_extend(handle,

			ext4_blocks_for_truncate(inode) + extra_credits);

		if (err > 0)

			err = ext4_journal_restart(handle,

			ext4_blocks_for_truncate(inode) + extra_credits);

		if (err != 0) {

			ext4_warning(inode->i_sb,

				     "couldn't extend journal (err %d)", err);

			goto stop_handle;

		}

	}



	inode->i_size = 0;

	err = ext4_mark_inode_dirty(handle, inode);

	if (err) {
@@ -298,26 +275,18 @@ void ext4_evict_inode(struct inode *inode) 
		}

	}



	/*

	 * ext4_ext_truncate() doesn't reserve any slop when it

	 * restarts journal transactions; therefore there may not be

	 * enough credits left in the handle to remove the inode from

	 * the orphan list and set the dtime field.

	 */

	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {

		err = ext4_journal_extend(handle, extra_credits);

		if (err > 0)

			err = ext4_journal_restart(handle, extra_credits);

		if (err != 0) {

			ext4_warning(inode->i_sb,

				     "couldn't extend journal (err %d)", err);

	/* Remove xattr references. */

	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,

				      extra_credits);

	if (err) {

		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);

stop_handle:

		ext4_journal_stop(handle);

		ext4_orphan_del(NULL, inode);

		sb_end_intwrite(inode->i_sb);

		ext4_xattr_inode_array_free(ea_inode_array);

		goto no_delete;

	}

	}



	/*

	 * Kill off the orphan record which ext4_truncate created.
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode) 
		ext4_clear_inode(inode);

	else

		ext4_free_inode(handle, inode);



	ext4_journal_stop(handle);

	sb_end_intwrite(inode->i_sb);

	ext4_xattr_inode_array_free(ea_inode_array);

fs/ext4/xattr.c

+165 −93
Original line number Diff line number Diff line
@@ -108,6 +108,10 @@ const struct xattr_handler *ext4_xattr_handlers[] = { 
#define EA_BLOCK_CACHE(inode)	(((struct ext4_sb_info *) \

				inode->i_sb->s_fs_info)->s_ea_block_cache)



static int

ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,

			struct inode *inode);



#ifdef CONFIG_LOCKDEP

void ext4_xattr_inode_set_class(struct inode *ea_inode)

{
@@ -652,6 +656,128 @@ static void ext4_xattr_update_super_block(handle_t *handle, 
	}

}



static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,

				     int credits, struct buffer_head *bh,

				     bool dirty, bool block_csum)

{

	int error;



	if (!ext4_handle_valid(handle))

		return 0;



	if (handle->h_buffer_credits >= credits)

		return 0;



	error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);

	if (!error)

		return 0;

	if (error < 0) {

		ext4_warning(inode->i_sb, "Extend journal (error %d)", error);

		return error;

	}



	if (bh && dirty) {

		if (block_csum)

			ext4_xattr_block_csum_set(inode, bh);

		error = ext4_handle_dirty_metadata(handle, NULL, bh);

		if (error) {

			ext4_warning(inode->i_sb, "Handle metadata (error %d)",

				     error);

			return error;

		}

	}



	error = ext4_journal_restart(handle, credits);

	if (error) {

		ext4_warning(inode->i_sb, "Restart journal (error %d)", error);

		return error;

	}



	if (bh) {

		error = ext4_journal_get_write_access(handle, bh);

		if (error) {

			ext4_warning(inode->i_sb,

				     "Get write access failed (error %d)",

				     error);

			return error;

		}

	}

	return 0;

}



static void

ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,

			    struct buffer_head *bh,

			    struct ext4_xattr_entry *first, bool block_csum,

			    struct ext4_xattr_inode_array **ea_inode_array,

			    int extra_credits)

{

	struct inode *ea_inode;

	struct ext4_xattr_entry *entry;

	bool dirty = false;

	unsigned int ea_ino;

	int err;

	int credits;



	/* One credit for dec ref on ea_inode, one for orphan list addition, */

	credits = 2 + extra_credits;



	for (entry = first; !IS_LAST_ENTRY(entry);

	     entry = EXT4_XATTR_NEXT(entry)) {

		if (!entry->e_value_inum)

			continue;

		ea_ino = le32_to_cpu(entry->e_value_inum);

		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);

		if (err)

			continue;



		err = ext4_expand_inode_array(ea_inode_array, ea_inode);

		if (err) {

			ext4_warning_inode(ea_inode,

					   "Expand inode array err=%d", err);

			iput(ea_inode);

			continue;

		}



		err = ext4_xattr_ensure_credits(handle, parent, credits, bh,

						dirty, block_csum);

		if (err) {

			ext4_warning_inode(ea_inode, "Ensure credits err=%d",

					   err);

			continue;

		}



		inode_lock(ea_inode);

		clear_nlink(ea_inode);

		ext4_orphan_add(handle, ea_inode);

		inode_unlock(ea_inode);



		/*

		 * Forget about ea_inode within the same transaction that

		 * decrements the ref count. This avoids duplicate decrements in

		 * case the rest of the work spills over to subsequent

		 * transactions.

		 */

		entry->e_value_inum = 0;

		entry->e_value_size = 0;



		dirty = true;

	}



	if (dirty) {

		/*

		 * Note that we are deliberately skipping csum calculation for

		 * the final update because we do not expect any journal

		 * restarts until xattr block is freed.

		 */



		err = ext4_handle_dirty_metadata(handle, NULL, bh);

		if (err)

			ext4_warning_inode(parent,

					   "handle dirty metadata err=%d", err);

	}

}



/*

 * Release the xattr block BH: If the reference count is > 1, decrement it;

 * otherwise free the block.
@@ -1982,42 +2108,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array, 
	return 0;

}



/**

 * Add xattr inode to orphan list

 */

static int

ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits,

			    struct ext4_xattr_inode_array *ea_inode_array)

{

	int idx = 0, error = 0;

	struct inode *ea_inode;



	if (ea_inode_array == NULL)

		return 0;



	for (; idx < ea_inode_array->count; ++idx) {

		if (!ext4_handle_has_enough_credits(handle, credits)) {

			error = ext4_journal_extend(handle, credits);

			if (error > 0)

				error = ext4_journal_restart(handle, credits);



			if (error != 0) {

				ext4_warning(inode->i_sb,

					"couldn't extend journal "

					"(err %d)", error);

				return error;

			}

		}

		ea_inode = ea_inode_array->inodes[idx];

		inode_lock(ea_inode);

		ext4_orphan_add(handle, ea_inode);

		inode_unlock(ea_inode);

		/* the inode's i_count will be released by caller */

	}



	return 0;

}



/*

 * ext4_xattr_delete_inode()

 *
@@ -2030,16 +2120,23 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits, 
 */

int

ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,

			struct ext4_xattr_inode_array **ea_inode_array)

			struct ext4_xattr_inode_array **ea_inode_array,

			int extra_credits)

{

	struct buffer_head *bh = NULL;

	struct ext4_xattr_ibody_header *header;

	struct ext4_inode *raw_inode;

	struct ext4_iloc iloc;

	struct ext4_xattr_entry *entry;

	struct inode *ea_inode;

	unsigned int ea_ino;

	int credits = 3, error = 0;

	struct ext4_iloc iloc = { .bh = NULL };

	int error;



	error = ext4_xattr_ensure_credits(handle, inode, extra_credits,

					  NULL /* bh */,

					  false /* dirty */,

					  false /* block_csum */);

	if (error) {

		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);

		goto cleanup;

	}



	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))

		goto delete_external_ea;
@@ -2047,31 +2144,20 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, 
	error = ext4_get_inode_loc(inode, &iloc);

	if (error)

		goto cleanup;

	raw_inode = ext4_raw_inode(&iloc);

	header = IHDR(inode, raw_inode);

	for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);

	     entry = EXT4_XATTR_NEXT(entry)) {

		if (!entry->e_value_inum)

			continue;

		ea_ino = le32_to_cpu(entry->e_value_inum);

		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);



	error = ext4_journal_get_write_access(handle, iloc.bh);

	if (error)

			continue;

		error = ext4_expand_inode_array(ea_inode_array, ea_inode);

		if (error) {

			iput(ea_inode);

			brelse(iloc.bh);

		goto cleanup;

		}

		entry->e_value_inum = 0;

	}

	brelse(iloc.bh);



	raw_inode = ext4_raw_inode(&iloc);

	header = IHDR(inode, raw_inode);

	ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),

				    false /* block_csum */, ea_inode_array,

				    extra_credits);



delete_external_ea:

	if (!EXT4_I(inode)->i_file_acl) {

		/* add xattr inode to orphan list */

		error = ext4_xattr_inode_orphan_add(handle, inode, credits,

						    *ea_inode_array);

		error = 0;

		goto cleanup;

	}

	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
@@ -2089,46 +2175,32 @@ delete_external_ea: 
		goto cleanup;

	}



	for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);

	     entry = EXT4_XATTR_NEXT(entry)) {

		if (!entry->e_value_inum)

			continue;

		ea_ino = le32_to_cpu(entry->e_value_inum);

		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);

		if (error)

			continue;

		error = ext4_expand_inode_array(ea_inode_array, ea_inode);

		if (error)

			goto cleanup;

		entry->e_value_inum = 0;

	}



	/* add xattr inode to orphan list */

	error = ext4_xattr_inode_orphan_add(handle, inode, credits,

					*ea_inode_array);

	if (error)

		goto cleanup;



	if (!IS_NOQUOTA(inode))

		credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);



	if (!ext4_handle_has_enough_credits(handle, credits)) {

		error = ext4_journal_extend(handle, credits);

		if (error > 0)

			error = ext4_journal_restart(handle, credits);

	if (ext4_has_feature_ea_inode(inode->i_sb)) {

		error = ext4_journal_get_write_access(handle, bh);

		if (error) {

			ext4_warning(inode->i_sb,

				"couldn't extend journal (err %d)", error);

			EXT4_ERROR_INODE(inode, "write access %llu",

					 EXT4_I(inode)->i_file_acl);

			goto cleanup;

		}

		ext4_xattr_inode_remove_all(handle, inode, bh,

					    BFIRST(bh),

					    true /* block_csum */,

					    ea_inode_array,

					    extra_credits);

	}



	ext4_xattr_release_block(handle, inode, bh);

	/* Update i_file_acl within the same transaction that releases block. */

	EXT4_I(inode)->i_file_acl = 0;



	error = ext4_mark_inode_dirty(handle, inode);

	if (error) {

		EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",

				 error);

		goto cleanup;

	}

cleanup:

	brelse(iloc.bh);

	brelse(bh);



	return error;

}

fs/ext4/xattr.h

+2 −1
Original line number Diff line number Diff line
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len); 


extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);

extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,

				   struct ext4_xattr_inode_array **array);

				   struct ext4_xattr_inode_array **array,

				   int extra_credits);

extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);



extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,

CRA Git | Maintained and supported by SUSTech CRA and CCSE