From 5328e635315734d42080de9a5a1ee87bf4cae0a4 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Thu, 19 Nov 2009 14:25:42 -0500 Subject: [PATCH] ext4: make trim/discard optional (and off by default) It is anticipated that when sb_issue_discard starts doing real work on trim-capable devices, we may see issues. Make this mount-time optional, and default it to off until we know that things are working out OK. Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" --- Documentation/filesystems/ext4.txt | 6 ++++++ fs/ext4/ext4.h | 1 + fs/ext4/mballoc.c | 21 +++++++++++++-------- fs/ext4/super.c | 14 +++++++++++++- 4 files changed, 33 insertions(+), 9 deletions(-) diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 6d94e0696f8c..26904ff6d61b 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -353,6 +353,12 @@ noauto_da_alloc replacing existing files via patterns such as system crashes before the delayed allocation blocks are forced to disk. +discard Controls whether ext4 should issue discard/TRIM +nodiscard(*) commands to the underlying block device when + blocks are freed. This is useful for SSD devices + and sparse/thinly-provisioned LUNs, but it is off + by default until sufficient testing has been done. + Data Mode ========= There are 3 different data modes: diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 8825515eeddd..05ce38b981cb 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -750,6 +750,7 @@ struct ext4_inode_info { #define EXT4_MOUNT_DELALLOC 0x8000000 /* Delalloc support */ #define EXT4_MOUNT_DATA_ERR_ABORT 0x10000000 /* Abort on file data write */ #define EXT4_MOUNT_BLOCK_VALIDITY 0x20000000 /* Block validity checking */ +#define EXT4_MOUNT_DISCARD 0x40000000 /* Issue DISCARD requests */ #define clear_opt(o, opt) o &= ~EXT4_MOUNT_##opt #define set_opt(o, opt) o |= EXT4_MOUNT_##opt diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index bba12824defa..6e5a23a2cc25 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2529,7 +2529,6 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) struct ext4_group_info *db; int err, count = 0, count2 = 0; struct ext4_free_data *entry; - ext4_fsblk_t discard_block; struct list_head *l, *ltmp; list_for_each_safe(l, ltmp, &txn->t_private_list) { @@ -2559,13 +2558,19 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) page_cache_release(e4b.bd_bitmap_page); } ext4_unlock_group(sb, entry->group); - discard_block = (ext4_fsblk_t) entry->group * EXT4_BLOCKS_PER_GROUP(sb) - + entry->start_blk - + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); - trace_ext4_discard_blocks(sb, (unsigned long long)discard_block, - entry->count); - sb_issue_discard(sb, discard_block, entry->count); - + if (test_opt(sb, DISCARD)) { + ext4_fsblk_t discard_block; + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + + discard_block = (ext4_fsblk_t)entry->group * + EXT4_BLOCKS_PER_GROUP(sb) + + entry->start_blk + + le32_to_cpu(es->s_first_data_block); + trace_ext4_discard_blocks(sb, + (unsigned long long)discard_block, + entry->count); + sb_issue_discard(sb, discard_block, entry->count); + } kmem_cache_free(ext4_free_ext_cachep, entry); ext4_mb_release_desc(&e4b); } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f2d5ec77c1e9..2b382f6f80c1 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -899,6 +899,9 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs) if (test_opt(sb, NO_AUTO_DA_ALLOC)) seq_puts(seq, ",noauto_da_alloc"); + if (test_opt(sb, DISCARD)) + seq_puts(seq, ",discard"); + ext4_show_quota_options(seq, sb); return 0; @@ -1079,7 +1082,8 @@ enum { Opt_usrquota, Opt_grpquota, Opt_i_version, Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_block_validity, Opt_noblock_validity, - Opt_inode_readahead_blks, Opt_journal_ioprio + Opt_inode_readahead_blks, Opt_journal_ioprio, + Opt_discard, Opt_nodiscard, }; static const match_table_t tokens = { @@ -1144,6 +1148,8 @@ static const match_table_t tokens = { {Opt_auto_da_alloc, "auto_da_alloc=%u"}, {Opt_auto_da_alloc, "auto_da_alloc"}, {Opt_noauto_da_alloc, "noauto_da_alloc"}, + {Opt_discard, "discard"}, + {Opt_nodiscard, "nodiscard"}, {Opt_err, NULL}, }; @@ -1565,6 +1571,12 @@ set_qf_format: else set_opt(sbi->s_mount_opt,NO_AUTO_DA_ALLOC); break; + case Opt_discard: + set_opt(sbi->s_mount_opt, DISCARD); + break; + case Opt_nodiscard: + clear_opt(sbi->s_mount_opt, DISCARD); + break; default: ext4_msg(sb, KERN_ERR, "Unrecognized mount option \"%s\" " -- 2.20.1