From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Date: Tue, 08 Mar 2011 13:53:44 +0800 Subject: [Ocfs2-devel] [PATCH 1/3] ocfs2: Add ocfs2_trim_fs for SSD trim support. In-Reply-To: <4D75B6DF.3030508@oracle.com> References: <4D74AD52.4030502@tao.ma> <1299492356-7329-1-git-send-email-tm@tao.ma> <4D75B6DF.3030508@oracle.com> Message-ID: <4D75C468.8050707@tao.ma> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com On 03/08/2011 12:55 PM, Tristan Ye wrote: > Hi Tao, > > Most of codes looks pretty neat to me, few comments inlined below: Thanks for the review. > > Tao Ma wrote: >> From: Tao Ma >> >> Add ocfs2_trim_fs to support trimming freed clusters in the >> volume. A range will be given and all the freed clusters greater >> than minlen will be discarded to the block layer. >> >> Signed-off-by: Tao Ma >> --- >> fs/ocfs2/alloc.c | 154 >> ++++++++++++++++++++++++++++++++++++++++++++++++++++++ >> fs/ocfs2/alloc.h | 1 + >> 2 files changed, 155 insertions(+), 0 deletions(-) >> >> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c >> index b27a0d8..6e1b3b5 100644 >> --- a/fs/ocfs2/alloc.c >> +++ b/fs/ocfs2/alloc.c >> @@ -29,6 +29,7 @@ >> #include >> #include >> #include >> +#include >> >> #include >> >> @@ -7184,3 +7185,156 @@ out_commit: >> out: >> return ret; >> } >> + >> +static int ocfs2_trim_extent(struct super_block *sb, >> + struct ocfs2_group_desc *gd, >> + int start, int count) >> +{ >> + u64 discard; >> + >> + count = ocfs2_clusters_to_blocks(sb, count); >> + discard = le64_to_cpu(gd->bg_blkno) + >> + ocfs2_clusters_to_blocks(sb, start); >> + >> + return sb_issue_discard(sb, discard, count, GFP_NOFS, 0); >> +} >> + >> +static int ocfs2_trim_group(struct super_block *sb, >> + struct ocfs2_group_desc *gd, >> + int start, int max, int minbits) >> +{ >> + int ret = 0, count = 0, next; >> + void *bitmap = gd->bg_bitmap; >> + >> + while (start < max) { >> + start = ocfs2_find_next_zero_bit(bitmap, max, start); >> + if (start >= max) >> + break; > > /* What if the 'start' stands within a hole */ > > if (ocfs2_test_bit(...)) { > start = ocfs2_find_next_zero_bit(...); > if ((start == -1) || (start >= max)) > break; > } > >> + next = ocfs2_find_next_bit(bitmap, max, start); > next = ocfs2_find_next_bit(...); > if (next == -1) > break; next will be set to "-1"? sorry, but where do you get it? > > if (next > max) > next = max; again, ocfs2_find_next_bit will return a value larger than 'max'? I am afraid not. Otherwise, it will be nonsense to pass a 'max' to it. > >> + >> + if ((next - start) >= minbits) { >> + ret = ocfs2_trim_extent(sb, gd, >> + start, next - start); >> + if (ret < 0) { >> + mlog_errno(ret); >> + break; >> + } >> + count += next - start; >> + } >> + start = next + 1; >> + >> + if (fatal_signal_pending(current)) { >> + count = -ERESTARTSYS; >> + break; >> + } >> + >> + if ((le16_to_cpu(gd->bg_free_bits_count) - count) < minbits) >> + break; >> + } >> + >> + if (ret < 0) >> + count = ret; >> + >> + return count; >> +} >> + >> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range) >> +{ >> + struct ocfs2_super *osb = OCFS2_SB(sb); >> + u64 start, len, minlen, trimmed, first_group, last_group, group; > why not using u32 start, len, minlen, trimmed; we may use 64 bit clusters later I guess. And what's more, they will be set by the user later. and it may overflow. Say the user pass a u64 range->len, it will overflow with range->len >> osb->s_clustersize_bits. >> + int ret, cnt, first_bit, last_bit; >> + struct buffer_head *main_bm_bh = NULL; >> + struct inode *main_bm_inode = NULL; >> + struct buffer_head *gd_bh = NULL; >> + struct ocfs2_dinode *main_bm; >> + struct ocfs2_group_desc *gd = NULL; >> + >> + if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) >> + return -EROFS; >> + >> + start = range->start >> osb->s_clustersize_bits; >> + len = range->len >> osb->s_clustersize_bits; >> + minlen = range->minlen >> osb->s_clustersize_bits; > > I guess you may want to count two corner clusters which cover the > 'start' and 'end' bytes, > so the appropriate way might be: > > start = range->start >> osb->s_clustersize_bits; > len = ocfs2_clusters_for_bytes(osb->sb, range->start + range->len); > len -= start; No, I don't want that.. Just want to make it the same as what ext4 did. See ext4_trim_fs for more details. > >> + trimmed = 0; >> + >> + if (!len || !minlen || minlen >= osb->bitmap_cpg) > 'minlen == 0' looks acceptable, which means we allowing discarding > for all size of extents. > and what's more, 'len == 0' may not be harmful enough to issue a > 'EINVAL', returning a legal '0' > to userspace immediately is fine. Fair enough. I will change it. Thanks. > > >> + return -EINVAL; >> + >> + main_bm_inode = ocfs2_get_system_file_inode(osb, >> + GLOBAL_BITMAP_SYSTEM_INODE, >> + OCFS2_INVALID_SLOT); >> + if (!main_bm_inode) { >> + ret = -EIO; >> + mlog_errno(ret); >> + goto out; >> + } >> + >> + mutex_lock(&main_bm_inode->i_mutex); >> + >> + ret = ocfs2_inode_lock(main_bm_inode, &main_bm_bh, 0); >> + if (ret < 0) { >> + mlog_errno(ret); >> + goto out_mutex; >> + } >> + main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data; >> + >> + if (start >= le32_to_cpu(main_bm->i_clusters)) { >> + ret = -EINVAL; >> + mlog_errno(ret); >> + goto out_unlock; >> + } >> + >> + if (start + len > le32_to_cpu(main_bm->i_clusters)) >> + len = le32_to_cpu(main_bm->i_clusters) - start; >> + >> + /* Determine first and last group to examine based on start and >> len */ >> + first_group = ocfs2_which_cluster_group(main_bm_inode, start); >> + if (first_group == osb->first_cluster_group_blkno) >> + first_bit = start; >> + else >> + first_bit = start - ocfs2_blocks_to_clusters(sb, first_group); >> + last_group = ocfs2_which_cluster_group(main_bm_inode, start + len >> - 1); >> + last_bit = osb->bitmap_cpg; >> + >> + for (group = first_group; group <= last_group;) { >> + if (first_bit + len >= osb->bitmap_cpg) >> + last_bit = osb->bitmap_cpg - first_bit; > > is 'first_bit' and 'last_bit' both represent a local offset within a > cluster group? > just wondering why last_bit wasn't equal to 'osb->bitmap_cpg' in above > case(I meant the case > of 'first_bit + len >= osb->bitmap_cpg' > >> + else >> + last_bit = start + len; > > why above case is not 'last_bit = first_bit + len'; you are right. Thanks. Regards, Tao