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Message-Id: <1262807223.17552.23.camel@mingming-laptop>
Date: Wed, 06 Jan 2010 11:47:03 -0800
From: Mingming <cmm@...ibm.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc: tytso@....edu, sandeen@...hat.com, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 1/3] ext4: Fix quota accounting error with fallocate
On Thu, 2010-01-07 at 00:52 +0530, Aneesh Kumar K.V wrote:
> When we fallocate a region of the file which we had recently written,
> and which is still in the page cache marked as delayed allocated blocks
> we need to make sure we don't do the quota update on writepage path.
> This is because the needed quota updated would have already be done
> by fallocate.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
> ---
> fs/ext4/ext4.h | 2 ++
> fs/ext4/extents.c | 21 +++++++++++++++++++++
> fs/ext4/inode.c | 35 +++++++++++++++++++++++------------
> 3 files changed, 46 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index af7b626..b98de17 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1443,6 +1443,8 @@ extern int ext4_block_truncate_page(handle_t *handle,
> extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
> extern qsize_t *ext4_get_reserved_space(struct inode *inode);
> extern int flush_aio_dio_completed_IO(struct inode *inode);
> +extern void ext4_da_update_reserve_space(struct inode *inode,
> + int used, int quota_claim);
> /* ioctl.c */
> extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
> extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 7d7b74e..3b6ff72 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3132,7 +3132,19 @@ out:
> unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
> newblock + max_blocks,
> allocated - max_blocks);
> + allocated = max_blocks;
> }
> +
> + /*
> + * If we have done fallocate with the offset that is already
> + * delayed allocated, we would have block reservation
> + * and quota reservation done in the delayed write path.
> + * But fallocate would have already updated quota and block
> + * count for this offset. So cancel these reservation
> + */
> + if (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE)
> + ext4_da_update_reserve_space(inode, allocated, 0);
> +
Looks right to me, we are only updating the reserve space in the delayed
buffered IO case, but avoid updating the quota.
> map_out:
> set_buffer_mapped(bh_result);
> out1:
> @@ -3368,9 +3380,18 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
> /* previous routine could use block we allocated */
> newblock = ext_pblock(&newex);
> allocated = ext4_ext_get_actual_len(&newex);
> + if (allocated > max_blocks)
> + allocated = max_blocks;
> set_buffer_new(bh_result);
>
> /*
> + * Update reserved blocks/metadata blocks after successful
> + * block allocation which had been deferred till now.
> + */
> + if (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE)
> + ext4_da_update_reserve_space(inode, allocated, 1);
> +
> + /*
> * Cache the extent and update transaction to commit on fdatasync only
> * when it is _not_ an uninitialized extent.
> */
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index c818972..3d1a1d6 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1053,7 +1053,8 @@ static int ext4_calc_metadata_amount(struct inode *inode, sector_t lblock)
> * Called with i_data_sem down, which is important since we can call
> * ext4_discard_preallocations() from here.
> */
> -static void ext4_da_update_reserve_space(struct inode *inode, int used)
> +void ext4_da_update_reserve_space(struct inode *inode,
> + int used, int quota_claim)
> {
> struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> struct ext4_inode_info *ei = EXT4_I(inode);
> @@ -1090,9 +1091,17 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
> spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
>
> /* Update quota subsystem */
> - vfs_dq_claim_block(inode, used);
> - if (mdb_free)
> - vfs_dq_release_reservation_block(inode, mdb_free);
> + if (quota_claim) {
> + vfs_dq_claim_block(inode, used);
> + if (mdb_free)
> + vfs_dq_release_reservation_block(inode, mdb_free);
> + } else {
> + /*
> + * This is a request to cancel the reservation. So just
> + * update the resevation and cancel the quota reservation
> + */
> + vfs_dq_release_reservation_block(inode, mdb_free + used);
> + }
>
> /*
> * If we have done all the pending block allocations and if
> @@ -1292,18 +1301,20 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
> */
> EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
> }
> - }
>
> + /*
> + * Update reserved blocks/metadata blocks after successful
> + * block allocation which had been deferred till now. We don't
> + * support fallocate for non extent files. So we can update
> + * reserve space here.
> + */
> + if ((retval > 0) &&
> + (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
> + ext4_da_update_reserve_space(inode, retval, 1);
> + }
> if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
> EXT4_I(inode)->i_delalloc_reserved_flag = 0;
>
> - /*
> - * Update reserved blocks/metadata blocks after successful
> - * block allocation which had been deferred till now.
> - */
> - if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
> - ext4_da_update_reserve_space(inode, retval);
> -
> up_write((&EXT4_I(inode)->i_data_sem));
> if (retval > 0 && buffer_mapped(bh)) {
> int ret = check_block_validity(inode, "file system "
Looks good,
Reviewed-by: Mingming Cao<cmm@...ibm.com>
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