ext4: use ext4_get_block_write in buffer write
Allocate uninitialized extent before ext4 buffer write and
convert the extent to initialized after io completes.
The purpose is to make sure an extent can only be marked
initialized after it has been written with new data so
we can safely drop the i_mutex lock in ext4 DIO read without
exposing stale data. This helps to improve multi-thread DIO
read performance on high-speed disks.
Skip the nobh and data=journal mount cases to make things simple for now.
Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dc7a97e..5e8f907 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -709,6 +709,7 @@
ei->i_reserved_quota = 0;
#endif
INIT_LIST_HEAD(&ei->i_completed_io_list);
+ spin_lock_init(&ei->i_completed_io_lock);
ei->cur_aio_dio = NULL;
ei->i_sync_tid = 0;
ei->i_datasync_tid = 0;
@@ -926,6 +927,9 @@
if (test_opt(sb, NOLOAD))
seq_puts(seq, ",norecovery");
+ if (test_opt(sb, DIOREAD_NOLOCK))
+ seq_puts(seq, ",dioread_nolock");
+
ext4_show_quota_options(seq, sb);
return 0;
@@ -1109,6 +1113,7 @@
Opt_stripe, Opt_delalloc, Opt_nodelalloc,
Opt_block_validity, Opt_noblock_validity,
Opt_inode_readahead_blks, Opt_journal_ioprio,
+ Opt_dioread_nolock, Opt_dioread_lock,
Opt_discard, Opt_nodiscard,
};
@@ -1176,6 +1181,8 @@
{Opt_auto_da_alloc, "auto_da_alloc=%u"},
{Opt_auto_da_alloc, "auto_da_alloc"},
{Opt_noauto_da_alloc, "noauto_da_alloc"},
+ {Opt_dioread_nolock, "dioread_nolock"},
+ {Opt_dioread_lock, "dioread_lock"},
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
{Opt_err, NULL},
@@ -1640,6 +1647,12 @@
case Opt_nodiscard:
clear_opt(sbi->s_mount_opt, DISCARD);
break;
+ case Opt_dioread_nolock:
+ set_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+ break;
+ case Opt_dioread_lock:
+ clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+ break;
default:
ext4_msg(sb, KERN_ERR,
"Unrecognized mount option \"%s\" "
@@ -2795,7 +2808,7 @@
EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
ext4_msg(sb, KERN_ERR, "required journal recovery "
"suppressed and not mounted read-only");
- goto failed_mount4;
+ goto failed_mount_wq;
} else {
clear_opt(sbi->s_mount_opt, DATA_FLAGS);
set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
@@ -2808,7 +2821,7 @@
!jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
JBD2_FEATURE_INCOMPAT_64BIT)) {
ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
- goto failed_mount4;
+ goto failed_mount_wq;
}
if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
@@ -2847,7 +2860,7 @@
(sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
ext4_msg(sb, KERN_ERR, "Journal does not support "
"requested data journaling mode");
- goto failed_mount4;
+ goto failed_mount_wq;
}
default:
break;
@@ -2855,13 +2868,17 @@
set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
no_journal:
-
if (test_opt(sb, NOBH)) {
if (!(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)) {
ext4_msg(sb, KERN_WARNING, "Ignoring nobh option - "
"its supported only with writeback mode");
clear_opt(sbi->s_mount_opt, NOBH);
}
+ if (test_opt(sb, DIOREAD_NOLOCK)) {
+ ext4_msg(sb, KERN_WARNING, "dioread_nolock option is "
+ "not supported with nobh mode");
+ goto failed_mount_wq;
+ }
}
EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
if (!EXT4_SB(sb)->dio_unwritten_wq) {
@@ -2926,6 +2943,18 @@
"requested data journaling mode");
clear_opt(sbi->s_mount_opt, DELALLOC);
}
+ if (test_opt(sb, DIOREAD_NOLOCK)) {
+ if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+ ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
+ "option - requested data journaling mode");
+ clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+ }
+ if (sb->s_blocksize < PAGE_SIZE) {
+ ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
+ "option - block size is too small");
+ clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+ }
+ }
err = ext4_setup_system_zone(sb);
if (err) {