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Message-Id: <1213284316-22063-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Date: Thu, 12 Jun 2008 20:55:16 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: cmm@...ibm.com, tytso@....edu, sandeen@...hat.com
Cc: linux-ext4@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [RFC PATCH] ext4: Add ordered mode support for delalloc
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
fs/ext4/inode.c | 169 +++++++++++++++++++++++++++++++++++++++++++++++++++--
fs/jbd2/commit.c | 41 ++++++++++++--
2 files changed, 198 insertions(+), 12 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 63355ab..7d87641 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1606,13 +1606,12 @@ static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
return !buffer_mapped(bh) || buffer_delay(bh);
}
-/* FIXME!! only support data=writeback mode */
/*
* get called vi ext4_da_writepages after taking page lock
* We may end up doing block allocation here in case
* mpage_da_map_blocks failed to allocate blocks.
*/
-static int ext4_da_writepage(struct page *page,
+static int ext4_da_writeback_writepage(struct page *page,
struct writeback_control *wbc)
{
int ret = 0;
@@ -1660,6 +1659,61 @@ static int ext4_da_writepage(struct page *page,
return ret;
}
+/*
+ * get called vi ext4_da_writepages after taking page lock
+ * We may end up doing block allocation here in case
+ * mpage_da_map_blocks failed to allocate blocks.
+ *
+ * We also get called via journal_submit_inode_data_buffers
+ */
+static int ext4_da_ordered_writepage(struct page *page,
+ struct writeback_control *wbc)
+{
+ int ret = 0;
+ loff_t size;
+ unsigned long len;
+ handle_t *handle = NULL;
+ struct buffer_head *page_bufs;
+ struct inode *inode = page->mapping->host;
+
+ handle = ext4_journal_current_handle();
+ if (!handle) {
+ /*
+ * This can happen when we aren't called via
+ * ext4_da_writepages() but directly (shrink_page_list).
+ * We cannot easily start a transaction here so we just skip
+ * writing the page in case we would have to do so.
+ */
+ size = i_size_read(inode);
+
+ page_bufs = page_buffers(page);
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+
+ if (walk_page_buffers(NULL, page_bufs, 0,
+ len, NULL, ext4_bh_unmapped_or_delay)) {
+ /*
+ * We can't do block allocation under
+ * page lock without a handle . So redirty
+ * the page and return.
+ * We may reach here when we do a journal commit
+ * via journal_submit_inode_data_buffers.
+ * If we don't have mapping block we just ignore
+ * them
+ *
+ */
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ return 0;
+ }
+ }
+
+ ret = block_write_full_page(page, ext4_da_get_block_write, wbc);
+
+ return ret;
+}
/*
* For now just follow the DIO way to estimate the max credits
@@ -1745,19 +1799,99 @@ static int ext4_da_writepages(struct address_space *mapping,
return ret;
}
+static int ext4_da_ordered_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct inode *inode = mapping->host;
+ handle_t *handle = NULL;
+ int needed_blocks;
+ int ret = 0;
+ long to_write;
+ loff_t range_start = 0;
+
+
+ /*
+ * No pages to write? This is mainly a kludge to avoid starting
+ * a transaction for special inodes like journal inode on last iput()
+ * because that could violate lock ordering on umount
+ */
+ if (!mapping->nrpages)
+ return 0;
+
+ /*
+ * Estimate the worse case needed credits to write out
+ * EXT4_MAX_BUF_BLOCKS pages
+ */
+ needed_blocks = EXT4_MAX_WRITEBACK_CREDITS;
+
+ to_write = wbc->nr_to_write;
+ if (!wbc->range_cyclic) {
+ /*
+ * If range_cyclic is not set force range_cont
+ * and save the old writeback_index
+ */
+ wbc->range_cont = 1;
+ range_start = wbc->range_start;
+ }
+
+ while (!ret && to_write) {
+ /* start a new transaction*/
+ handle = ext4_journal_start(inode, needed_blocks);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out_writepages;
+ }
+
+ ret = ext4_jbd2_file_inode(handle, inode);
+ if (ret) {
+ ext4_journal_stop(handle);
+ goto out_writepages;
+ }
+ /*
+ * set the max dirty pages could be write at a time
+ * to fit into the reserved transaction credits
+ */
+ if (wbc->nr_to_write > EXT4_MAX_WRITEBACK_PAGES)
+ wbc->nr_to_write = EXT4_MAX_WRITEBACK_PAGES;
+
+ to_write -= wbc->nr_to_write;
+ ret = mpage_da_writepages(mapping, wbc,
+ ext4_da_get_block_write);
+ ext4_journal_stop(handle);
+ if (wbc->nr_to_write) {
+ /*
+ * There is no more writeout needed
+ * or we requested for a noblocking writeout
+ * and we found the device congested
+ */
+ to_write += wbc->nr_to_write;
+ break;
+ }
+ wbc->nr_to_write = to_write;
+ }
+
+out_writepages:
+ wbc->nr_to_write = to_write;
+ if (range_start)
+ wbc->range_start = range_start;
+ return ret;
+}
+
static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
- int ret;
+ int ret, retries = 0;
struct page *page;
pgoff_t index;
unsigned from, to;
+ struct inode *inode = mapping->host;
index = pos >> PAGE_CACHE_SHIFT;
from = pos & (PAGE_CACHE_SIZE - 1);
to = from + len;
+retry:
page = __grab_cache_page(mapping, index);
if (!page)
return -ENOMEM;
@@ -1770,6 +1904,9 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
page_cache_release(page);
}
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+
return ret;
}
@@ -2224,10 +2361,10 @@ static int ext4_journalled_set_page_dirty(struct page *page)
.releasepage = ext4_releasepage,
};
-static const struct address_space_operations ext4_da_aops = {
+static const struct address_space_operations ext4_da_writeback_aops = {
.readpage = ext4_readpage,
.readpages = ext4_readpages,
- .writepage = ext4_da_writepage,
+ .writepage = ext4_da_writeback_writepage,
.writepages = ext4_da_writepages,
.sync_page = block_sync_page,
.write_begin = ext4_da_write_begin,
@@ -2239,13 +2376,31 @@ static int ext4_journalled_set_page_dirty(struct page *page)
.migratepage = buffer_migrate_page,
};
+static const struct address_space_operations ext4_da_ordered_aops = {
+ .readpage = ext4_readpage,
+ .readpages = ext4_readpages,
+ .writepage = ext4_da_ordered_writepage,
+ .writepages = ext4_da_ordered_writepages,
+ .sync_page = block_sync_page,
+ .write_begin = ext4_da_write_begin,
+ .write_end = generic_write_end,
+ .bmap = ext4_bmap,
+ .invalidatepage = ext4_da_invalidatepage,
+ .releasepage = ext4_releasepage,
+ .direct_IO = ext4_direct_IO,
+ .migratepage = buffer_migrate_page,
+};
+
void ext4_set_aops(struct inode *inode)
{
- if (ext4_should_order_data(inode))
+ if (ext4_should_order_data(inode) &&
+ test_opt(inode->i_sb, DELALLOC))
+ inode->i_mapping->a_ops = &ext4_da_ordered_aops;
+ else if (ext4_should_order_data(inode))
inode->i_mapping->a_ops = &ext4_ordered_aops;
else if (ext4_should_writeback_data(inode) &&
test_opt(inode->i_sb, DELALLOC))
- inode->i_mapping->a_ops = &ext4_da_aops;
+ inode->i_mapping->a_ops = &ext4_da_writeback_aops;
else if (ext4_should_writeback_data(inode))
inode->i_mapping->a_ops = &ext4_writeback_aops;
else
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 483183d..32ca3c3 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -22,6 +22,8 @@
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/crc32.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -185,6 +187,30 @@ static int journal_wait_on_commit_record(struct buffer_head *bh)
}
/*
+ * write the filemap data using writepage() address_space_operations.
+ * We don't do block allocation here even for delalloc. We don't
+ * use writepages() because with dealyed allocation we may be doing
+ * block allocation in writepages().
+ */
+static int journal_submit_inode_data_buffers(struct address_space *mapping)
+{
+ int ret;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = mapping->nrpages * 2,
+ .range_start = 0,
+ .range_end = i_size_read(mapping->host),
+ .for_writepages = 1,
+ };
+
+ if (!mapping_cap_writeback_dirty(mapping))
+ return 0;
+
+ ret = generic_writepages(mapping, &wbc);
+ return ret;
+}
+
+/*
* Submit all the data buffers of inode associated with the transaction to
* disk.
*
@@ -192,7 +218,7 @@ static int journal_wait_on_commit_record(struct buffer_head *bh)
* our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
* operate on from being released while we write out pages.
*/
-static int journal_submit_inode_data_buffers(journal_t *journal,
+static int journal_submit_data_buffers(journal_t *journal,
transaction_t *commit_transaction)
{
struct jbd2_inode *jinode;
@@ -204,8 +230,13 @@ static int journal_submit_inode_data_buffers(journal_t *journal,
mapping = jinode->i_vfs_inode->i_mapping;
jinode->i_flags |= JI_COMMIT_RUNNING;
spin_unlock(&journal->j_list_lock);
- err = filemap_fdatawrite_range(mapping, 0,
- i_size_read(jinode->i_vfs_inode));
+ /*
+ * submit the inode data buffers. We use writepage
+ * instead of writepages. Because writepages can do
+ * block allocation with delalloc. We need to write
+ * only allocated blocks here.
+ */
+ err = journal_submit_inode_data_buffers(mapping);
if (!ret)
ret = err;
spin_lock(&journal->j_list_lock);
@@ -228,7 +259,7 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
struct jbd2_inode *jinode, *next_i;
int err, ret = 0;
- /* For locking, see the comment in journal_submit_inode_data_buffers() */
+ /* For locking, see the comment in journal_submit_data_buffers() */
spin_lock(&journal->j_list_lock);
list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
jinode->i_flags |= JI_COMMIT_RUNNING;
@@ -431,7 +462,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
* Now start flushing things to disk, in the order they appear
* on the transaction lists. Data blocks go first.
*/
- err = journal_submit_inode_data_buffers(journal, commit_transaction);
+ err = journal_submit_data_buffers(journal, commit_transaction);
if (err)
jbd2_journal_abort(journal, err);
--
1.5.6.rc2.15.g457bb.dirty
--
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