Commit afc7cbca authored by Takashi Sato's avatar Takashi Sato Committed by Theodore Ts'o

ext4: Support large blocksize up to PAGESIZE

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: default avatarTakashi Sato <sho@tnes.nec.co.jp>
Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
parent 8561b089
...@@ -1624,6 +1624,11 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent) ...@@ -1624,6 +1624,11 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
goto out_fail; 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 * The ext4 superblock will not be buffer aligned for other than 1kB
* block sizes. We need to calculate the offset from buffer start. * block sizes. We need to calculate the offset from buffer start.
......
...@@ -73,8 +73,8 @@ ...@@ -73,8 +73,8 @@
* Macro-instructions used to manage several block sizes * Macro-instructions used to manage several block sizes
*/ */
#define EXT4_MIN_BLOCK_SIZE 1024 #define EXT4_MIN_BLOCK_SIZE 1024
#define EXT4_MAX_BLOCK_SIZE 4096 #define EXT4_MAX_BLOCK_SIZE 65536
#define EXT4_MIN_BLOCK_LOG_SIZE 10 #define EXT4_MIN_BLOCK_LOG_SIZE 10
#ifdef __KERNEL__ #ifdef __KERNEL__
# define EXT4_BLOCK_SIZE(s) ((s)->s_blocksize) # define EXT4_BLOCK_SIZE(s) ((s)->s_blocksize)
#else #else
......
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