Bad performance results with the latest git patches

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Hi Alex,

running ffsb tests (large files creation) on my system with the latest ext4 git patches against a 2.6.23-rc4 kernel, I've got very bad performance results: the I/O throughput measured on an ext4 filesystem is ten times lower than those measured on an XFS filesystem on the same machine. I have mounted the ext4 filesytem with mballoc, delalloc and data=writeback options.

dmesg output shows plenty of error messages like this:

EXT4-fs error (device sdc): ext4_ext_search_right: bad header in inode #3745797: unexpected eh_depth - magic f30a, entries 81, max 84(0), depth 0(1) EXT4-fs error (device sdc): ext4_ext_search_right: bad header in inode #3745797: unexpected eh_depth - magic f30a, entries 81, max 84(0), depth 0(1) EXT4-fs error (device sdc): ext4_ext_search_right: bad header in inode #3745797: unexpected eh_depth - magic f30a, entries 81, max 84(0), depth 0(1) EXT4-fs error (device sdc): ext4_ext_search_right: bad header in inode #3745797: unexpected eh_depth - magic f30a, entries 81, max 84(0), depth 0(1)


If I removed the second call to ext4_ext_check_header() in the ext4_ext_search_right() function, the problem disappears, no more error messages and better throughput values close to those measured on the XFS filesystem.
It seems that the depth value passed in argument is buggy.

In a previous line,
  while (++depth < path->p_depth) {
the depth value is incremented even if we don't enter the loop. Is it the problem ?

Could you check this?
Thanks,
  Valérie
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