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 [email protected]'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.
Signed-off-by: Greg Harm <[email protected]>
---
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
On 2011-10-28, at 12:01 PM, Greg Harm <[email protected]> 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 [email protected]'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.
> Signed-off-by: Greg Harm <[email protected]>
> ---
> 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
>
On Fri, Oct 28, 2011 at 11:47 AM, Andreas Dilger <[email protected]> wrote:
> On 2011-10-28, at 12:01 PM, Greg Harm <[email protected]> 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 [email protected]'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 <[email protected]>
>> ---
>> 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
>>
>
On Fri, Oct 28, 2011 at 11:01:57AM -0700, Greg Harm 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 [email protected]'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.
>
> Signed-off-by: Greg Harm <[email protected]>
Thanks, I had to tweak the patch slightly to make it apply given the
current ext4 tree.
- Ted
commit 5f11e7c457769808bafe5048a98c5cfd624e85f3
Author: Greg Harm <[email protected]>
Date: Mon Oct 31 18:41:47 2011 -0400
ext4: Don't normalize an falloc request if it can fit in 1 extent.
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 commit 556b27abf73: 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.
Signed-off-by: Greg Harm <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e585caa..9dfdf8f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4336,10 +4336,16 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
return ret;
}
- flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
- EXT4_GET_BLOCKS_NO_NORMALIZE;
+ flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT;
if (mode & FALLOC_FL_KEEP_SIZE)
flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
+ /*
+ * 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)
+ flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
retry:
while (ret >= 0 && ret < max_blocks) {
map.m_lblk = map.m_lblk + ret;