On Fri, Dec 2, 2011 at 4:55 AM, Allison Henderson <achender@xxxxxxxxxxxxxxxxxx> wrote: > On 11/16/2011 07:03 PM, Yongqiang Yang wrote: >> >> Punch hole should never call ext4_ext_insert_extent, so this patch >> removes code related to it from ext4_ext_insert_extent. >> >> Signed-off-by: Yongqiang Yang<xiaoqiangnk@xxxxxxxxx> >> --- >> fs/ext4/extents.c | 2 -- >> 1 files changed, 0 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >> index 6888d1a..720070d 100644 >> --- a/fs/ext4/extents.c >> +++ b/fs/ext4/extents.c >> @@ -1737,8 +1737,6 @@ int ext4_ext_insert_extent(handle_t *handle, struct >> inode *inode, >> * There is no free space in the found leaf. >> * We're gonna add a new leaf in the tree. >> */ >> - if (flag& EXT4_GET_BLOCKS_PUNCH_OUT_EXT) >> - flags = EXT4_MB_USE_ROOT_BLOCKS; >> err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext); >> if (err) >> goto cleanup; > > Hi Yongqiang, > > Actually I believe it does end up inserting an extent if an extent gets > split. For example, we punch a hole in the middle of an extent, so we first > split the extent into three pieces, and remove the middle piece. > > Because inserting the extra extents can require extra blocks, the operation > may temporarily consume blocks. The problem that this causes is that if the > file system is really full, it can fail with ENOSPC, even though punch hole > is an operation that is supposed to free blocks. The above > EXT4_MB_USE_ROOT_BLOCKS flag was put in so that when we punch holes, we can > borrow reserved blocks to complete the operation to avoid the ENOSPC > problem. I had a script to catch this and added to xfstests (test 256). So > unless there was a change somewhere that I missed, it does not make sense to > me to take it out at this point. Got it. Thank you for your explanation. Yongqiang. > > Allison Henderson > > -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
