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Date: Tue, 20 Feb 2018 12:20:05 +0200
From: Nikolay Borisov <nborisov@...e.com>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, jack@...e.cz, Nikolay Borisov <nborisov@...e.com>
Subject: [PATCH] ext4: Remove EXT4_STATE_DIOREAD_LOCK flag
Commit 16c54688592c ("ext4: Allow parallel DIO reads") reworked the way
locking happens around parallel dio reads. This resulted in obviating
the need for EXT4_STATE_DIOREAD_LOCK flag and accompanying logic.
Currently this amounts to dead code so let's remove it. No functional
changes
Signed-off-by: Nikolay Borisov <nborisov@...e.com>
---
fs/ext4/ext4.h | 17 -----------------
fs/ext4/extents.c | 19 +++++--------------
fs/ext4/inode.c | 8 --------
fs/ext4/ioctl.c | 4 ----
fs/ext4/move_extent.c | 4 ----
fs/ext4/super.c | 12 +++++-------
6 files changed, 10 insertions(+), 54 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 3241475a1733..a42e71203e53 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1522,8 +1522,6 @@ enum {
EXT4_STATE_EXT_MIGRATE, /* Inode is migrating */
EXT4_STATE_DIO_UNWRITTEN, /* need convert on dio done*/
EXT4_STATE_NEWENTRY, /* File just added to dir */
- EXT4_STATE_DIOREAD_LOCK, /* Disable support for dio read
- nolocking */
EXT4_STATE_MAY_INLINE_DATA, /* may have in-inode data */
EXT4_STATE_EXT_PRECACHED, /* extents have been precached */
EXT4_STATE_LUSTRE_EA_INODE, /* Lustre-style ea_inode */
@@ -3181,21 +3179,6 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh)
set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
}
-/*
- * Disable DIO read nolock optimization, so new dioreaders will be forced
- * to grab i_mutex
- */
-static inline void ext4_inode_block_unlocked_dio(struct inode *inode)
-{
- ext4_set_inode_state(inode, EXT4_STATE_DIOREAD_LOCK);
- smp_mb();
-}
-static inline void ext4_inode_resume_unlocked_dio(struct inode *inode)
-{
- smp_mb();
- ext4_clear_inode_state(inode, EXT4_STATE_DIOREAD_LOCK);
-}
-
#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
/* For ioend & aio unwritten conversion wait queues */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 054416e9d827..837f0a6357c7 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4796,7 +4796,6 @@ static long ext4_zero_range(struct file *file, loff_t offset,
flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
/* Wait all existing dio workers, newcomers will block on i_mutex */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
/* Preallocate the range including the unaligned edges */
@@ -4807,7 +4806,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
round_down(offset, 1 << blkbits)) >> blkbits,
new_size, flags);
if (ret)
- goto out_dio;
+ goto out_mutex;
}
@@ -4824,7 +4823,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
ret = ext4_update_disksize_before_punch(inode, offset, len);
if (ret) {
up_write(&EXT4_I(inode)->i_mmap_sem);
- goto out_dio;
+ goto out_mutex;
}
/* Now release the pages and zero block aligned part of pages */
truncate_pagecache_range(inode, start, end - 1);
@@ -4834,10 +4833,10 @@ static long ext4_zero_range(struct file *file, loff_t offset,
flags);
up_write(&EXT4_I(inode)->i_mmap_sem);
if (ret)
- goto out_dio;
+ goto out_mutex;
}
if (!partial_begin && !partial_end)
- goto out_dio;
+ goto out_mutex;
/*
* In worst case we have to writeout two nonadjacent unwritten
@@ -4850,7 +4849,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
ext4_std_error(inode->i_sb, ret);
- goto out_dio;
+ goto out_mutex;
}
inode->i_mtime = inode->i_ctime = current_time(inode);
@@ -4875,8 +4874,6 @@ static long ext4_zero_range(struct file *file, loff_t offset,
ext4_handle_sync(handle);
ext4_journal_stop(handle);
-out_dio:
- ext4_inode_resume_unlocked_dio(inode);
out_mutex:
inode_unlock(inode);
return ret;
@@ -4964,11 +4961,9 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
}
/* Wait all existing dio workers, newcomers will block on i_mutex */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
- ext4_inode_resume_unlocked_dio(inode);
if (ret)
goto out;
@@ -5485,7 +5480,6 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
}
/* Wait for existing dio to complete */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
/*
@@ -5562,7 +5556,6 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
ext4_journal_stop(handle);
out_mmap:
up_write(&EXT4_I(inode)->i_mmap_sem);
- ext4_inode_resume_unlocked_dio(inode);
out_mutex:
inode_unlock(inode);
return ret;
@@ -5635,7 +5628,6 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
}
/* Wait for existing dio to complete */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
/*
@@ -5737,7 +5729,6 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
ext4_journal_stop(handle);
out_mmap:
up_write(&EXT4_I(inode)->i_mmap_sem);
- ext4_inode_resume_unlocked_dio(inode);
out_mutex:
inode_unlock(inode);
return ret;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c94780075b04..7d285e79fd9f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4251,7 +4251,6 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
}
/* Wait all existing dio workers, newcomers will block on i_mutex */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
/*
@@ -4324,7 +4323,6 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
ext4_journal_stop(handle);
out_dio:
up_write(&EXT4_I(inode)->i_mmap_sem);
- ext4_inode_resume_unlocked_dio(inode);
out_mutex:
inode_unlock(inode);
return ret;
@@ -5506,9 +5504,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
*/
if (orphan) {
if (!ext4_should_journal_data(inode)) {
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
- ext4_inode_resume_unlocked_dio(inode);
} else
ext4_wait_for_tail_page_commit(inode);
}
@@ -5999,7 +5995,6 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
return -EROFS;
/* Wait for all existing dio workers */
- ext4_inode_block_unlocked_dio(inode);
inode_dio_wait(inode);
/*
@@ -6015,7 +6010,6 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
err = filemap_write_and_wait(inode->i_mapping);
if (err < 0) {
up_write(&EXT4_I(inode)->i_mmap_sem);
- ext4_inode_resume_unlocked_dio(inode);
return err;
}
}
@@ -6038,7 +6032,6 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
if (err < 0) {
jbd2_journal_unlock_updates(journal);
percpu_up_write(&sbi->s_journal_flag_rwsem);
- ext4_inode_resume_unlocked_dio(inode);
return err;
}
ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
@@ -6050,7 +6043,6 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
if (val)
up_write(&EXT4_I(inode)->i_mmap_sem);
- ext4_inode_resume_unlocked_dio(inode);
/* Finally we can mark the inode as dirty. */
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7e99ad02f1ba..3644e31ba347 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -124,8 +124,6 @@ static long swap_inode_boot_loader(struct super_block *sb,
truncate_inode_pages(&inode_bl->i_data, 0);
/* Wait for all existing dio workers */
- ext4_inode_block_unlocked_dio(inode);
- ext4_inode_block_unlocked_dio(inode_bl);
inode_dio_wait(inode);
inode_dio_wait(inode_bl);
@@ -186,8 +184,6 @@ static long swap_inode_boot_loader(struct super_block *sb,
ext4_double_up_write_data_sem(inode, inode_bl);
journal_err_out:
- ext4_inode_resume_unlocked_dio(inode);
- ext4_inode_resume_unlocked_dio(inode_bl);
unlock_two_nondirectories(inode, inode_bl);
iput(inode_bl);
return err;
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index b96e4bd3b3ec..8e17efdcbf11 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -601,8 +601,6 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
lock_two_nondirectories(orig_inode, donor_inode);
/* Wait for all existing dio workers */
- ext4_inode_block_unlocked_dio(orig_inode);
- ext4_inode_block_unlocked_dio(donor_inode);
inode_dio_wait(orig_inode);
inode_dio_wait(donor_inode);
@@ -693,8 +691,6 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
ext4_ext_drop_refs(path);
kfree(path);
ext4_double_up_write_data_sem(orig_inode, donor_inode);
- ext4_inode_resume_unlocked_dio(orig_inode);
- ext4_inode_resume_unlocked_dio(donor_inode);
unlock_two_nondirectories(orig_inode, donor_inode);
return ret;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 39bf464c35f1..8781f8afbe50 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -101,15 +101,13 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb,
* i_data_sem (rw)
*
* truncate:
- * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (w) -> i_mmap_sem (w) ->
- * i_mmap_rwsem (w) -> page lock
- * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (w) -> i_mmap_sem (w) ->
- * transaction start -> i_data_sem (rw)
+ * sb_start_write -> i_mutex -> i_mmap_sem (w) -> i_mmap_rwsem (w) -> page lock
+ * sb_start_write -> i_mutex -> i_mmap_sem (w) -> transaction start ->
+ * i_data_sem (rw)
*
* direct IO:
- * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (r) -> mmap_sem
- * sb_start_write -> i_mutex -> EXT4_STATE_DIOREAD_LOCK (r) ->
- * transaction start -> i_data_sem (rw)
+ * sb_start_write -> i_mutex -> mmap_sem
+ * sb_start_write -> i_mutex -> transaction start -> i_data_sem (rw)
*
* writepages:
* transaction start -> page lock(s) -> i_data_sem (rw)
--
2.7.4
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