Re: btrfs fallocate woes

Aneesh Kumar K. V
2010-01-20T07:28:54Z

On Tue, 19 Jan 2010 15:18:26 +0000, Paul Komkoff <i@stingr.net> wrote:
> On Thu, Jan 14, 2010 at 8:33 PM, Paul Komkoff <i@stingr.net> wrote:
> > If it's fixed in latest tree it's fine, I guess that fix isn't in
> > fedora's 2.6.32.3
>
> Sorry for popping up again, but did anyone fix this/verified there's
> no problem in recent kernels? For some reasons I cannot run latest git
> so I'm stuck with fedora kernels, and every one I have around me (with
> btrfs) has this problem.
>

the below change fixes this for me on btrfs

commit f2bc9dd07e3424c4ec5f3949961fe053d47bc825
Author: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Wed Jan 20 12:57:53 2010 +0530

btrfs: Use correct values when updating inode i_size on fallocate

Even though we allocate more, we should be updating inode i_size
as per the arguments passed

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5440bab..db406a4 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5789,7 +5789,7 @@ out_fail:
}

static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
- u64 alloc_hint, int mode)
+ u64 alloc_hint, int mode, loff_t actual_len)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -5798,6 +5798,7 @@ static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
u64 cur_offset = start;
u64 num_bytes = end - start;
int ret = 0;
+ u64 i_size;

while (num_bytes > 0) {
alloc_size = min(num_bytes, root->fs_info->max_extent);
@@ -5836,8 +5837,12 @@ static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
cur_offset > inode->i_size) {
- i_size_write(inode, cur_offset);
- btrfs_ordered_update_i_size(inode, cur_offset, NULL);
+ if (cur_offset > actual_len)
+ i_size = actual_len;
+ else
+ i_size = cur_offset;
+ i_size_write(inode, i_size);
+ btrfs_ordered_update_i_size(inode, i_size, NULL);
}

ret = btrfs_update_inode(trans, root, inode);
@@ -5930,7 +5935,7 @@ static long btrfs_fallocate(struct inode *inode, int mode,
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
ret = prealloc_file_range(inode,
cur_offset, last_byte,
- alloc_hint, mode);
+ alloc_hint, mode, offset+len);
if (ret < 0) {
free_extent_map(em);
break;