Remove the mark_inode_dirty call from __generic_write_end and add it to
generic_write_end and the high-level iomap functions where necessary.
That way, large writes will only dirty inodes at the end instead of
dirtying them once per page. This fixes a performance bottleneck on
gfs2.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
fs/buffer.c | 26 ++++++++++++++++++--------
fs/iomap.c | 42 ++++++++++++++++++++++++++++++++++++++----
2 files changed, 56 insertions(+), 12 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index e450c55f6434..1b51003bc9d2 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2089,8 +2089,7 @@ EXPORT_SYMBOL(block_write_begin);
void __generic_write_end(struct inode *inode, loff_t pos, unsigned copied,
struct page *page)
{
- loff_t old_size = inode->i_size;
- bool i_size_changed = false;
+ loff_t old_size;
/*
* No need to use i_size_read() here, the i_size cannot change under us
@@ -2099,23 +2098,21 @@ void __generic_write_end(struct inode *inode, loff_t pos, unsigned copied,
* But it's important to update i_size while still holding page lock:
* page writeout could otherwise come in and zero beyond i_size.
*/
- if (pos + copied > inode->i_size) {
+ old_size = inode->i_size;
+ if (pos + copied > old_size)
i_size_write(inode, pos + copied);
- i_size_changed = true;
- }
unlock_page(page);
if (old_size < pos)
pagecache_isize_extended(inode, old_size, pos);
+
/*
* Don't mark the inode dirty under page lock. First, it unnecessarily
* makes the holding time of page lock longer. Second, it forces lock
* ordering of page lock and transaction start for journaling
* filesystems.
*/
- if (i_size_changed)
- mark_inode_dirty(inode);
}
int block_write_end(struct file *file, struct address_space *mapping,
@@ -2158,9 +2155,22 @@ int generic_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
+ struct inode *inode = mapping->host;
+ loff_t old_size;
+
+ /*
+ * No need to use i_size_read() here, the i_size cannot change under us
+ * because we hold i_rwsem.
+ */
+ old_size = inode->i_size;
+
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
- __generic_write_end(mapping->host, pos, copied, page);
+ __generic_write_end(inode, pos, copied, page);
put_page(page);
+
+ if (old_size != inode->i_size)
+ mark_inode_dirty(inode);
+
return copied;
}
EXPORT_SYMBOL(generic_write_end);
diff --git a/fs/iomap.c b/fs/iomap.c
index 23ef63fd1669..9454568a7f5e 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -881,6 +881,13 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
loff_t pos = iocb->ki_pos, ret = 0, written = 0;
+ loff_t old_size;
+
+ /*
+ * No need to use i_size_read() here, the i_size cannot change under us
+ * because we hold i_rwsem.
+ */
+ old_size = inode->i_size;
while (iov_iter_count(iter)) {
ret = iomap_apply(inode, pos, iov_iter_count(iter),
@@ -891,6 +898,9 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
written += ret;
}
+ if (old_size != inode->i_size)
+ mark_inode_dirty(inode);
+
return written ? written : ret;
}
EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
@@ -961,18 +971,30 @@ int
iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
const struct iomap_ops *ops)
{
+ loff_t old_size;
loff_t ret;
+ /*
+ * No need to use i_size_read() here, the i_size cannot change under us
+ * because we hold i_rwsem.
+ */
+ old_size = inode->i_size;
+
while (len) {
ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
iomap_dirty_actor);
if (ret <= 0)
- return ret;
+ goto out;
pos += ret;
len -= ret;
}
+ ret = 0;
- return 0;
+out:
+ if (old_size != inode->i_size)
+ mark_inode_dirty(inode);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(iomap_file_dirty);
@@ -1039,19 +1061,31 @@ int
iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
const struct iomap_ops *ops)
{
+ loff_t old_size;
loff_t ret;
+ /*
+ * No need to use i_size_read() here, the i_size cannot change under us
+ * because we hold i_rwsem.
+ */
+ old_size = inode->i_size;
+
while (len > 0) {
ret = iomap_apply(inode, pos, len, IOMAP_ZERO,
ops, did_zero, iomap_zero_range_actor);
if (ret <= 0)
- return ret;
+ goto out;
pos += ret;
len -= ret;
}
+ ret = 0;
- return 0;
+out:
+ if (old_size != inode->i_size)
+ mark_inode_dirty(inode);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(iomap_zero_range);
--
2.20.1
