On Fri, Oct 28, 2011 at 11:47 AM, Andreas Dilger <aedilger@xxxxxxxxx> wrote: > On 2011-10-28, at 12:01 PM, Greg Harm <gharm@xxxxxxxxxx> wrote: >> If an fallocate request fits in EXT_UNINIT_MAX_LEN, then set the >> EXT4_GET_BLOCKS_NO_NORMALIZE flag. For larger fallocate requests, >> let mballoc.c normalize the request. >> This fixes a problem where large requests were being split >> into non-contiguous extents due to haldar@xxxxxxxxxx's >> "ext4: do not normalize block requests from fallocate." >> >> Testing: Checked that 8.x MB falloc'ed files are still laid down >> next to each other (contiguously). >> Checked that the maximum size extent (127.9MB) is allocated as 1 >> extent. >> Checked that a 1GB file is somewhat contiguous (often 5-6 >> non-contiguous extents now). >> Checked that a 120MB file can still be falloc'ed even if there are no >> single extents large enough to hold it. > > It would be great to add these test cases to xfstests so that this doesn't break in the future. Hi Andreas, I totally agree. I have that on my TODO list (but no current ETA). Thanks, Greg >> Signed-off-by: Greg Harm <gharm@xxxxxxxxxx> >> --- >> fs/ext4/extents.c | 13 ++++++++++--- >> 1 files changed, 10 insertions(+), 3 deletions(-) >> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >> index 57cf568..9819216 100644 >> --- a/fs/ext4/extents.c >> +++ b/fs/ext4/extents.c >> @@ -3761,6 +3761,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >> int ret2 = 0; >> int retries = 0; >> struct ext4_map_blocks map; >> + int map_blocks_flags; >> unsigned int credits, blkbits = inode->i_blkbits; >> >> /* >> @@ -3805,9 +3806,15 @@ retry: >> ret = PTR_ERR(handle); >> break; >> } >> - ret = ext4_map_blocks(handle, inode, &map, >> - EXT4_GET_BLOCKS_CREATE_UNINIT_EXT | >> - EXT4_GET_BLOCKS_NO_NORMALIZE); >> + map_blocks_flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT; >> + /* >> + * Don't normalize the request if it can fit in one extent so >> + * that it doesn't get unnecessarily split into multiple >> + * extents. >> + */ >> + if (len <= EXT_UNINIT_MAX_LEN << blkbits) >> + map_blocks_flags |= EXT4_GET_BLOCKS_NO_NORMALIZE; >> + ret = ext4_map_blocks(handle, inode, &map, map_blocks_flags); >> if (ret <= 0) { >> #ifdef EXT4FS_DEBUG >> WARN_ON(ret <= 0); >> -- >> 1.7.3.1 >> > -- 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