Hi all,

Today's linux-next merge of the vfs-brauner tree got a conflict in:

  fs/jbd2/journal.c

between commit:

  bbe9015f23432b ("jbd2: remove special jbd2 slabs")

from the ext4 tree and commit:

  2f6702dc6fdcf0 ("jbd2: replace __get_free_pages() with kmalloc()")

from the vfs-brauner tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --combined fs/jbd2/journal.c
index 4fdf089500f618,e82798680109d3..00000000000000
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@@ -95,6 -95,8 +95,6 @@@ EXPORT_SYMBOL(jbd2_journal_release_jbd_
  EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
  EXPORT_SYMBOL(jbd2_inode_cache);
  
 -static int jbd2_journal_create_slab(size_t slab_size);
 -
  #ifdef CONFIG_JBD2_DEBUG
  void __jbd2_debug(int level, const char *file, const char *func,
  		  unsigned int line, const char *fmt, ...)
@@@ -383,10 -385,10 +383,10 @@@ int jbd2_journal_write_metadata_buffer(
  			goto escape_done;
  
  		spin_unlock(&jh_in->b_state_lock);
 -		tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS | __GFP_NOFAIL);
 +		tmp = kmalloc(bh_in->b_size, GFP_NOFS | __GFP_NOFAIL);
  		spin_lock(&jh_in->b_state_lock);
  		if (jh_in->b_frozen_data) {
 -			jbd2_free(tmp, bh_in->b_size);
 +			kfree(tmp);
  			goto copy_done;
  		}
  
@@@ -1818,9 -1820,7 +1818,7 @@@ static int jbd2_write_superblock(journa
  	}
  	if (jbd2_journal_has_csum_v2or3(journal))
  		sb->s_checksum = jbd2_superblock_csum(sb);
- 	get_bh(bh);
- 	bh->b_end_io = end_buffer_write_sync;
- 	submit_bh(REQ_OP_WRITE | write_flags, bh);
+ 	bh_submit(bh, REQ_OP_WRITE | write_flags, bh_end_write);
  	wait_on_buffer(bh);
  	if (buffer_write_io_error(bh)) {
  		clear_buffer_write_io_error(bh);
@@@ -2062,6 -2062,14 +2060,6 @@@ EXPORT_SYMBOL(jbd2_journal_update_sb_er
  int jbd2_journal_load(journal_t *journal)
  {
  	int err;
 -	journal_superblock_t *sb = journal->j_superblock;
 -
 -	/*
 -	 * Create a slab for this blocksize
 -	 */
 -	err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
 -	if (err)
 -		return err;
  
  	/* Let the recovery code check whether it needs to recover any
  	 * data from the journal. */
@@@ -2253,8 -2261,6 +2251,8 @@@ jbd2_journal_initialize_fast_commit(jou
  	unsigned long long num_fc_blks;
  
  	num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
 +	if (num_fc_blks > journal->j_last)
 +		return -EFSCORRUPTED;
  	if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
  		return -ENOSPC;
  
@@@ -2691,6 -2697,105 +2689,6 @@@ size_t journal_tag_bytes(journal_t *jou
  		return sz - sizeof(__u32);
  }
  
 -/*
 - * JBD memory management
 - *
 - * These functions are used to allocate block-sized chunks of memory
 - * used for making copies of buffer_head data.  Very often it will be
 - * page-sized chunks of data, but sometimes it will be in
 - * sub-page-size chunks.  (For example, 16k pages on Power systems
 - * with a 4k block file system.)  For blocks smaller than a page, we
 - * use a SLAB allocator.  There are slab caches for each block size,
 - * which are allocated at mount time, if necessary, and we only free
 - * (all of) the slab caches when/if the jbd2 module is unloaded.  For
 - * this reason we don't need to a mutex to protect access to
 - * jbd2_slab[] allocating or releasing memory; only in
 - * jbd2_journal_create_slab().
 - */
 -#define JBD2_MAX_SLABS 8
 -static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
 -
 -static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
 -	"jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
 -	"jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
 -};
 -
 -
 -static void jbd2_journal_destroy_slabs(void)
 -{
 -	int i;
 -
 -	for (i = 0; i < JBD2_MAX_SLABS; i++) {
 -		kmem_cache_destroy(jbd2_slab[i]);
 -		jbd2_slab[i] = NULL;
 -	}
 -}
 -
 -static int jbd2_journal_create_slab(size_t size)
 -{
 -	static DEFINE_MUTEX(jbd2_slab_create_mutex);
 -	int i = order_base_2(size) - 10;
 -	size_t slab_size;
 -
 -	if (size == PAGE_SIZE)
 -		return 0;
 -
 -	if (i >= JBD2_MAX_SLABS)
 -		return -EINVAL;
 -
 -	if (unlikely(i < 0))
 -		i = 0;
 -	mutex_lock(&jbd2_slab_create_mutex);
 -	if (jbd2_slab[i]) {
 -		mutex_unlock(&jbd2_slab_create_mutex);
 -		return 0;	/* Already created */
 -	}
 -
 -	slab_size = 1 << (i+10);
 -	jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
 -					 slab_size, 0, NULL);
 -	mutex_unlock(&jbd2_slab_create_mutex);
 -	if (!jbd2_slab[i]) {
 -		printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
 -		return -ENOMEM;
 -	}
 -	return 0;
 -}
 -
 -static struct kmem_cache *get_slab(size_t size)
 -{
 -	int i = order_base_2(size) - 10;
 -
 -	BUG_ON(i >= JBD2_MAX_SLABS);
 -	if (unlikely(i < 0))
 -		i = 0;
 -	BUG_ON(jbd2_slab[i] == NULL);
 -	return jbd2_slab[i];
 -}
 -
 -void *jbd2_alloc(size_t size, gfp_t flags)
 -{
 -	void *ptr;
 -
 -	BUG_ON(size & (size-1)); /* Must be a power of 2 */
 -
 -	if (size < PAGE_SIZE)
 -		ptr = kmem_cache_alloc(get_slab(size), flags);
 -	else
 -		ptr = kmalloc(size, flags);
 -
 -	/* Check alignment; SLUB has gotten this wrong in the past,
 -	 * and this can lead to user data corruption! */
 -	BUG_ON(((unsigned long) ptr) & (size-1));
 -
 -	return ptr;
 -}
 -
 -void jbd2_free(void *ptr, size_t size)
 -{
 -	kfree(ptr);
 -};
 -
  /*
   * Journal_head storage management
   */
@@@ -2864,15 -2969,15 +2862,15 @@@ static void __journal_remove_journal_he
  	clear_buffer_jbd(bh);
  }
  
 -static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
 +static void journal_release_journal_head(struct journal_head *jh)
  {
  	if (jh->b_frozen_data) {
  		printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
 -		jbd2_free(jh->b_frozen_data, b_size);
 +		kfree(jh->b_frozen_data);
  	}
  	if (jh->b_committed_data) {
  		printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
 -		jbd2_free(jh->b_committed_data, b_size);
 +		kfree(jh->b_committed_data);
  	}
  	journal_free_journal_head(jh);
  }
@@@ -2891,7 -2996,7 +2889,7 @@@ void jbd2_journal_put_journal_head(stru
  	if (!jh->b_jcount) {
  		__journal_remove_journal_head(bh);
  		jbd_unlock_bh_journal_head(bh);
 -		journal_release_journal_head(jh, bh->b_size);
 +		journal_release_journal_head(jh);
  		__brelse(bh);
  	} else {
  		jbd_unlock_bh_journal_head(bh);
@@@ -3033,6 -3138,7 +3031,6 @@@ static void jbd2_journal_destroy_caches
  	jbd2_journal_destroy_handle_cache();
  	jbd2_journal_destroy_inode_cache();
  	jbd2_journal_destroy_transaction_cache();
 -	jbd2_journal_destroy_slabs();
  }
  
  static int __init journal_init(void)

On Thu, Jun 11, 2026 at 02:45:44PM +0100, Mark Brown wrote:
> Hi all,
> 
> Today's linux-next merge of the vfs-brauner tree got a conflict in:
> 
>   fs/jbd2/journal.c
> 
> between commit:
> 
>   bbe9015f23432b ("jbd2: remove special jbd2 slabs")
> 
> from the ext4 tree and commit:
> 
>   2f6702dc6fdcf0 ("jbd2: replace __get_free_pages() with kmalloc()")
> 
> from the vfs-brauner tree.

2f6702dc6fdcf0 is a subset of bbe9015f23432b and should be dropped from
vfs-brauner.