在 2008-12-03三的 21:11 +0100,Jan Kara写道: > Hi, > > On Thu 06-11-08 15:39:05, Mingming Cao wrote: > > ext4: quota reservation for delayed allocation > > > > Uses quota reservation/claim/release to handle quota properly for delayed > > allocation in the three steps: 1) quotas are reserved when data being copied > > to cache when block allocation is defered 2) when new blocks are allocated. > > reserved quotas are converted to the real allocated quota, 2) over-booked > > quotas for metadata blocks are released back. > > > > > > Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx> > > --- > > fs/ext4/inode.c | 29 ++++++++++++++++++++++++++--- > > fs/ext4/mballoc.c | 42 +++++++++++++++++++++++++----------------- > > fs/ext4/super.c | 3 +++ > > 3 files changed, 54 insertions(+), 20 deletions(-) > > > > Index: linux-2.6.28-rc2/fs/ext4/inode.c > > =================================================================== > > --- linux-2.6.28-rc2.orig/fs/ext4/inode.c 2008-11-06 13:36:16.000000000 -0800 > > +++ linux-2.6.28-rc2/fs/ext4/inode.c 2008-11-06 14:03:35.000000000 -0800 > > @@ -994,7 +994,9 @@ static void ext4_da_update_reserve_space > > { > > struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > > int total, mdb, mdb_free; > > + int claim_quota, free_quota = 0; > > > > + claim_quota = used; > > spin_lock(&EXT4_I(inode)->i_block_reservation_lock); > > /* recalculate the number of metablocks still need to be reserved */ > > total = EXT4_I(inode)->i_reserved_data_blocks - used; > > @@ -1007,6 +1009,8 @@ static void ext4_da_update_reserve_space > > if (mdb_free) { > > /* Account for allocated meta_blocks */ > > mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks; > > + free_quota = mdb_free; > > + claim_quota += EXT4_I(inode)->i_allocated_meta_blocks; > > > > /* update fs dirty blocks counter */ > > percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free); > > @@ -1017,8 +1021,14 @@ static void ext4_da_update_reserve_space > > /* update per-inode reservations */ > > BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks); > > EXT4_I(inode)->i_reserved_data_blocks -= used; > > - > > spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); > > + > > + /* > > + * free those over-booking quota for metadata blocks > > + */ > > + > > + if (free_quota) > > + DQUOT_RELEASE_RSV_BLOCK(inode, free_quota); > claim_quota seems to be unused here and I'm not sure we need it for > anything... > Thanks for catching this, I will remove that variable. > > } > > > > /* > > @@ -1514,8 +1524,8 @@ static int ext4_journalled_write_end(str > > static int ext4_da_reserve_space(struct inode *inode, int nrblocks) > > { > > int retries = 0; > > - struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > > - unsigned long md_needed, mdblocks, total = 0; > > + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > > + unsigned long md_needed, mdblocks, total = 0; > > > > /* > > * recalculate the amount of metadata blocks to reserve > > @@ -1531,12 +1541,23 @@ repeat: > > md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks; > > total = md_needed + nrblocks; > > > > + /* > > + * Make quota reservation here to prevent quota overflow > > + * later. Real quota accounting is done at pages writeout > > + * time. > > + */ > > + if (DQUOT_RESERVE_BLOCK(inode, total)) { > > + spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); > > + return -EDQUOT; > > + } > > + > > if (ext4_claim_free_blocks(sbi, total)) { > > spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); > > if (ext4_should_retry_alloc(inode->i_sb, &retries)) { > > yield(); > > goto repeat; > > } > > + DQUOT_RELEASE_RSV_BLOCK(inode, total); > > return -ENOSPC; > > } > > EXT4_I(inode)->i_reserved_data_blocks += nrblocks; > > @@ -1590,6 +1611,8 @@ static void ext4_da_release_space(struct > > BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks); > > EXT4_I(inode)->i_reserved_meta_blocks = mdb; > > spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); > > + > > + DQUOT_RELEASE_RSV_BLOCK(inode, release); > > } > > > > static void ext4_da_page_release_reservation(struct page *page, > > Index: linux-2.6.28-rc2/fs/ext4/super.c > > =================================================================== > > --- linux-2.6.28-rc2.orig/fs/ext4/super.c 2008-11-06 13:36:16.000000000 -0800 > > +++ linux-2.6.28-rc2/fs/ext4/super.c 2008-11-06 14:02:57.000000000 -0800 > > @@ -795,6 +795,9 @@ static struct dquot_operations ext4_quot > > .initialize = ext4_dquot_initialize, > > .drop = ext4_dquot_drop, > > .alloc_space = dquot_alloc_space, > > + .reserve_space = dquot_reserve_space, > > + .claim_space = dquot_claim_space, > > + .release_rsv = dquot_release_reserved_space, > > .alloc_inode = dquot_alloc_inode, > > .free_space = dquot_free_space, > > .free_inode = dquot_free_inode, > > Index: linux-2.6.28-rc2/fs/ext4/mballoc.c > > =================================================================== > > --- linux-2.6.28-rc2.orig/fs/ext4/mballoc.c 2008-11-06 13:36:16.000000000 -0800 > > +++ linux-2.6.28-rc2/fs/ext4/mballoc.c 2008-11-06 14:03:35.000000000 -0800 > > @@ -2887,9 +2887,11 @@ ext4_mb_mark_diskspace_used(struct ext4_ > > if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) > > /* release all the reserved blocks if non delalloc */ > > percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks); > > - else > > + else { > > percpu_counter_sub(&sbi->s_dirtyblocks_counter, > > ac->ac_b_ex.fe_len); > > + DQUOT_CLAIM_BLOCK(ac->ac_inode, ac->ac_b_ex.fe_len); > > + } > > > > if (sbi->s_log_groups_per_flex) { > > ext4_group_t flex_group = ext4_flex_group(sbi, > > @@ -4286,15 +4288,24 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t > > struct ext4_sb_info *sbi; > > struct super_block *sb; > > ext4_fsblk_t block = 0; > > - unsigned long inquota; > > + unsigned long inquota = 0; > > unsigned long reserv_blks = 0; > > > > sb = ar->inode->i_sb; > > sbi = EXT4_SB(sb); > > > > - if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) { > > + /* > > + * For delayed allocation, we could skip the ENOSPC and > > + * EDQUOT check, as blocks and quotas have been already > > + * reserved when data being copied into pagecache. > > + */ > > + if (EXT4_I(ar->inode)->i_delalloc_reserved_flag) > > + ar->flags |= EXT4_MB_DELALLOC_RESERVED; > > + else { > > /* > > - * With delalloc we already reserved the blocks > > + * Without delayed allocation we need to verify > > + * there is enough free blocks to do block allocation > > + * and verify allocation doesn't exceed the quota limits. > > */ > > while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) { > > /* let others to free the space */ > > @@ -4306,19 +4317,16 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t > > return 0; > > } > > reserv_blks = ar->len; > > + while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) { > > + ar->flags |= EXT4_MB_HINT_NOPREALLOC; > > + ar->len--; > > + } > > + if (ar->len == 0) { > > + *errp = -EDQUOT; > > + return 0; > > + } > > + inquota = ar->len; > > } > > - while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) { > > - ar->flags |= EXT4_MB_HINT_NOPREALLOC; > > - ar->len--; > > - } > > - if (ar->len == 0) { > > - *errp = -EDQUOT; > > - return 0; > > - } > > - inquota = ar->len; > > - > > - if (EXT4_I(ar->inode)->i_delalloc_reserved_flag) > > - ar->flags |= EXT4_MB_DELALLOC_RESERVED; > > > > ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS); > > if (!ac) { > > @@ -4380,7 +4388,7 @@ repeat: > > out2: > > kmem_cache_free(ext4_ac_cachep, ac); > > out1: > > - if (ar->len < inquota) > > + if (inquota && ar->len < inquota) > > DQUOT_FREE_BLOCK(ar->inode, inquota - ar->len); > > > > return block; > > > > > > Honza -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html