145 lines
4.5 KiB
Diff
145 lines
4.5 KiB
Diff
From 994f567b2e99c82913a279ff438269c771b68a4b Mon Sep 17 00:00:00 2001
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From: Dmitry Monakhov <dmonakhov@openvz.org>
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Date: Sat, 29 Sep 2012 00:41:21 -0400
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Subject: [PATCH 05/13] ext4: serialize dio nonlocked reads with defrag
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workers
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Inode's block defrag and ext4_change_inode_journal_flag() may
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affect nonlocked DIO reads result, so proper synchronization
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required.
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- Add missed inode_dio_wait() calls where appropriate
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- Check inode state under extra i_dio_count reference.
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Reviewed-by: Jan Kara <jack@suse.cz>
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Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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(cherry picked from commit 17335dcc471199717839b2fa3492ca36f70f1168)
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Conflicts:
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fs/ext4/move_extent.c
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---
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fs/ext4/ext4.h | 17 +++++++++++++++++
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fs/ext4/indirect.c | 14 ++++++++++++++
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fs/ext4/inode.c | 5 +++++
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fs/ext4/move_extent.c | 8 ++++++++
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4 files changed, 44 insertions(+)
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diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
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index 7687d15..3e740e9 100644
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--- a/fs/ext4/ext4.h
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+++ b/fs/ext4/ext4.h
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@@ -1352,6 +1352,8 @@ enum {
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EXT4_STATE_DIO_UNWRITTEN, /* need convert on dio done*/
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EXT4_STATE_NEWENTRY, /* File just added to dir */
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EXT4_STATE_DELALLOC_RESERVED, /* blks already reserved for delalloc */
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+ EXT4_STATE_DIOREAD_LOCK, /* Disable support for dio read
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+ nolocking */
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};
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#define EXT4_INODE_BIT_FNS(name, field, offset) \
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@@ -2459,6 +2461,21 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh)
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set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
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}
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+/*
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+ * Disable DIO read nolock optimization, so new dioreaders will be forced
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+ * to grab i_mutex
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+ */
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+static inline void ext4_inode_block_unlocked_dio(struct inode *inode)
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+{
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+ ext4_set_inode_state(inode, EXT4_STATE_DIOREAD_LOCK);
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+ smp_mb();
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+}
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+static inline void ext4_inode_resume_unlocked_dio(struct inode *inode)
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+{
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+ smp_mb();
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+ ext4_clear_inode_state(inode, EXT4_STATE_DIOREAD_LOCK);
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+}
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+
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#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
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/* For ioend & aio unwritten conversion wait queues */
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diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
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index 61f13e5..8d849da 100644
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--- a/fs/ext4/indirect.c
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+++ b/fs/ext4/indirect.c
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@@ -810,11 +810,25 @@ retry:
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if (unlikely(!list_empty(&ei->i_completed_io_list)))
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ext4_flush_completed_IO(inode);
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+ /*
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+ * Nolock dioread optimization may be dynamically disabled
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+ * via ext4_inode_block_unlocked_dio(). Check inode's state
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+ * while holding extra i_dio_count ref.
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+ */
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+ atomic_inc(&inode->i_dio_count);
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+ smp_mb();
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+ if (unlikely(ext4_test_inode_state(inode,
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+ EXT4_STATE_DIOREAD_LOCK))) {
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+ inode_dio_done(inode);
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+ goto locked;
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+ }
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ret = __blockdev_direct_IO(rw, iocb, inode,
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inode->i_sb->s_bdev, iov,
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offset, nr_segs,
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ext4_get_block, NULL, NULL, 0);
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+ inode_dio_done(inode);
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} else {
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+locked:
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ret = blockdev_direct_IO(rw, iocb, inode, iov,
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offset, nr_segs, ext4_get_block);
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diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
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index dd3fd23..2bd7526 100644
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--- a/fs/ext4/inode.c
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+++ b/fs/ext4/inode.c
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@@ -4706,6 +4706,10 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
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return err;
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}
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+ /* Wait for all existing dio workers */
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+ ext4_inode_block_unlocked_dio(inode);
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+ inode_dio_wait(inode);
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+
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jbd2_journal_lock_updates(journal);
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/*
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@@ -4725,6 +4729,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
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ext4_set_aops(inode);
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jbd2_journal_unlock_updates(journal);
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+ ext4_inode_resume_unlocked_dio(inode);
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/* Finally we can mark the inode as dirty. */
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diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
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index c5826c6..fd1e32e 100644
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--- a/fs/ext4/move_extent.c
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+++ b/fs/ext4/move_extent.c
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@@ -1214,6 +1214,12 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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/* Protect orig and donor inodes against a truncate */
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mext_inode_double_lock(orig_inode, donor_inode);
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+ /* Wait for all existing dio workers */
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+ ext4_inode_block_unlocked_dio(orig_inode);
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+ ext4_inode_block_unlocked_dio(donor_inode);
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+ inode_dio_wait(orig_inode);
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+ inode_dio_wait(donor_inode);
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+
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/* Protect extent tree against block allocations via delalloc */
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double_down_write_data_sem(orig_inode, donor_inode);
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/* Check the filesystem environment whether move_extent can be done */
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@@ -1413,6 +1419,8 @@ out:
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kfree(holecheck_path);
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}
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double_up_write_data_sem(orig_inode, donor_inode);
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+ ext4_inode_resume_unlocked_dio(orig_inode);
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+ ext4_inode_resume_unlocked_dio(donor_inode);
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mext_inode_double_unlock(orig_inode, donor_inode);
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return ret;
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--
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1.7.12.rc0.22.gcdd159b
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