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From: Theodore Ts'o <tytso@mit.edu>
To: linux-kernel@vger.kernel.org
Cc: linux-ext4@vger.kernel.org, Takashi Sato <sho@tnes.nec.co.jp>,
	Mingming Cao <cmm@us.ibm.com>
Subject: [PATCH] Support large blocksize up to PAGESIZE (max 64KB) for ext4
Date: Thu,  4 Oct 2007 01:50:47 -0400	[thread overview]
Message-ID: <1191477059-5357-13-git-send-email-tytso@mit.edu> (raw)
In-Reply-To: <1191477059-5357-12-git-send-email-tytso@mit.edu>

From: Takashi Sato <sho@tnes.nec.co.jp>

This patch set supports large block size(>4k, <=64k) in ext4,
just enlarging the block size limit. But it is NOT possible to have 64kB
blocksize on ext4 without some changes to the directory handling
code.  The reason is that an empty 64kB directory block would have a
rec_len == (__u16)2^16 == 0, and this would cause an error to be hit in
the filesystem.  The proposed solution is treat 64k rec_len
with a an impossible value like rec_len = 0xffff to handle this.

The Patch-set consists of the following 2 patches.
  [1/2]  ext4: enlarge blocksize
         - Allow blocksize up to pagesize

  [2/2]  ext4: fix rec_len overflow
         - prevent rec_len from overflow with 64KB blocksize

Now on 64k page ppc64 box runs with this patch set we could create a 64k
block size ext4dev, and able to handle empty directory block.

Signed-off-by: Takashi Sato <sho@tnes.nec.co.jp>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
---
 fs/ext4/super.c         |    5 +++++
 include/linux/ext4_fs.h |    4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 619db84..d8bb279 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1548,6 +1548,11 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		goto out_fail;
 	}
 
+	if (!sb_set_blocksize(sb, blocksize)) {
+		printk(KERN_ERR "EXT4-fs: bad blocksize %d.\n", blocksize);
+		goto out_fail;
+	}
+
 	/*
 	 * The ext4 superblock will not be buffer aligned for other than 1kB
 	 * block sizes.  We need to calculate the offset from buffer start.
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index 46b304d..5d90616 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -73,8 +73,8 @@
  * Macro-instructions used to manage several block sizes
  */
 #define EXT4_MIN_BLOCK_SIZE		1024
-#define	EXT4_MAX_BLOCK_SIZE		4096
-#define EXT4_MIN_BLOCK_LOG_SIZE		  10
+#define	EXT4_MAX_BLOCK_SIZE		65536
+#define EXT4_MIN_BLOCK_LOG_SIZE		10
 #ifdef __KERNEL__
 # define EXT4_BLOCK_SIZE(s)		((s)->s_blocksize)
 #else
-- 
1.5.3.2.81.g17ed

  reply	other threads:[~2007-10-04  5:51 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-04  5:50 [PATCH, RFC] Ext4 patches planned for submission upstream Theodore Ts'o
2007-10-04  5:50 ` [PATCH] jbd/jbd2: JBD memory allocation cleanups Theodore Ts'o
2007-10-04  5:50   ` [PATCH] jbd/jbd2: Journal initialization doesn't need __GFP_NOFAIL Theodore Ts'o
2007-10-04  5:50     ` [PATCH] JBD2/Ext4: Convert kmalloc to kzalloc in jbd2/ext4 Theodore Ts'o
     [not found]       ` <1191477059-5357-5-git-send-email-tytso@mit.edu>
2007-10-04  5:50         ` [PATCH] jbd2: fix commit code to properly abort journal Theodore Ts'o
2007-10-04  5:50           ` [PATCH] JBD2: debug code cleanup Theodore Ts'o
2007-10-04  5:50             ` [PATCH] Once ext4 will not implement fragment, it is believed it will never be Theodore Ts'o
2007-10-04  5:50               ` [PATCH] ext4: remove #ifdef CONFIG_EXT4_INDEX Theodore Ts'o
2007-10-04  5:50                 ` [PATCH] Ext4: Uninitialized Block Groups Theodore Ts'o
2007-10-04  5:50                   ` [PATCH] ext4: Fix sparse warnings Theodore Ts'o
2007-10-04  5:50                     ` [PATCH] This feature relaxes check restrictions on where each block groups meta Theodore Ts'o
2007-10-04  5:50                       ` Theodore Ts'o [this message]
2007-10-04  5:50                         ` [PATCH] ext4: Avoid rec_len overflow with 64KB block size Theodore Ts'o
2007-10-04  5:50                           ` [PATCH] Support large blocksize up to PAGESIZE (max 64KB) for ext2 Theodore Ts'o
2007-10-04  5:50                             ` [PATCH] Support large blocksize up to PAGESIZE (max 64KB) for ext3 Theodore Ts'o
2007-10-04  5:50                               ` [PATCH] ext2: Avoid rec_len overflow with 64KB block size Theodore Ts'o
2007-10-04  5:50                                 ` [PATCH] ext3: " Theodore Ts'o
2007-10-04  5:50                                   ` [PATCH] ext4: Convert bg_block_bitmap to bg_block_bitmap_lo Theodore Ts'o
2007-10-04  5:50                                     ` [PATCH] ext4: Convert bg_inode_bitmap and bg_inode_table Theodore Ts'o
2007-10-04  5:50                                       ` [PATCH] ext4: Convert s_blocks_count to s_blocks_count_lo Theodore Ts'o
2007-10-04  5:50                                         ` [PATCH] ext4: Convert s_r_blocks_count and s_free_blocks_count Theodore Ts'o
2007-10-04  5:50                                           ` [PATCH] ext4: Convert ext4_extent.ee_start to ext4_extent.ee_start_lo Theodore Ts'o
2007-10-04  5:50                                             ` [PATCH] ext4: Convert ext4_extent_idx.ei_leaf to ext4_extent_idx.ei_leaf_lo Theodore Ts'o
2007-10-04  5:50                                               ` [PATCH] ext4: sparse fixes Theodore Ts'o
2007-10-04  6:52   ` [PATCH] jbd/jbd2: JBD memory allocation cleanups Christoph Hellwig
2007-10-05 22:33     ` Mingming Cao
2007-10-05 22:35     ` [PATCH] jbd: JBD slab " Mingming Cao
2007-10-05 22:36     ` [PATCH] jbd2: JBD2 " Mingming Cao
2007-10-05 22:38     ` [PATCH] jbd: JBD replace jbd_kmalloc with kmalloc Mingming Cao
2007-10-08 17:46       ` Christoph Lameter
2007-10-08 18:26         ` Mingming Cao
2007-10-08 18:34           ` Christoph Lameter
2007-10-05 22:39     ` [PATCH] jbd2: JBD replace jbd2_kmalloc " Mingming Cao
2007-10-08 18:37       ` Christoph Lameter

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