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f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages

PATCH Superseded Chao Yu 3 participants 6 messages May 16, 2014 – May 26, 2014

Subsystems (2)
VFS F2FS file system

v1 of 2 Superseded Latest is v2 →

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Chao Yu

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#0 lore raw

PATCH 1/1 f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +28 -21
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
 
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
 
 	for (; page_idx < start + nrpages; page_idx++) {
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:
-			list_del(&page->lru);
-			__free_pages(page, 0);
+			page_cache_release(pages[index]);
 		}
+
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }
Signature · 1 line
1.7.10.4
maintainer
#1 lore raw

Hi Chao,

2014-05-16 (금), 17:14 +0800, Chao Yu:

Quoted 53 lines

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +5 -2
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
 
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
 
 	for (; page_idx < start + nrpages; page_idx++) {

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, · line 1681

Quoted 10 lines
fs/f2fs/node.c +2 -5
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);

IMO, we don't need to do like this.
Instead,

	for() {
		page = grab_cache_page();
		if (!page)
			break;
		page[page_idx] = page;
		f2fs_submit_page_mbio(sbi, page, &fio);
	}
	f2fs_submit_merged_bio(sbi, META, READ);
	return page_idx - start;

Afterwards, in restore_node_summry(),

	lock_page() will wait the end_io for read.
	...
	f2fs_put_page(pages[index], 1);

Thanks,

Quoted 74 lines
fs/f2fs/node.c +21 -14
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:
-			list_del(&page->lru);
-			__free_pages(page, 0);
+			page_cache_release(pages[index]);
 		}
+
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }
Signature · 1 line
Jaegeuk Kim

------------------------------------------------------------------------------
"Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free."
http://p.sf.net/sfu/SauceLabs

_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

#2 lore raw
Quoted 36 lines · Jaegeuk Kim

Hi Chao,

2014-05-16 (금), 17:14 +0800, Chao Yu:

Quoted 33 lines

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +0 -0
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
Quoted 11 lines

fs/f2fs/node.c int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page) · line 1667

Quoted 11 lines
fs/f2fs/node.c +3 -2
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;

How about use sbi->meta_inode instead of bd_inode, then we can do caching summary pages for further i/o.

Quoted 105 lines
Quoted 9 lines
fs/f2fs/node.c +2 -0
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
 
 	for (; page_idx < start + nrpages; page_idx++) {

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, · line 1681

Quoted 10 lines
fs/f2fs/node.c +2 -5
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);

IMO, we don't need to do like this.
Instead,

	for() {
		page = grab_cache_page();
		if (!page)
			break;
		page[page_idx] = page;
		f2fs_submit_page_mbio(sbi, page, &fio);
	}
	f2fs_submit_merged_bio(sbi, META, READ);
	return page_idx - start;

Afterwards, in restore_node_summry(),

	lock_page() will wait the end_io for read.
	...
	f2fs_put_page(pages[index], 1);

Thanks,

Quoted 66 lines
fs/f2fs/node.c +17 -14
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:
-			list_del(&page->lru);
-			__free_pages(page, 0);
Quoted 25 lines
Quoted 8 lines
fs/f2fs/node.c +4 -0
+			page_cache_release(pages[index]);
 		}
+
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }
Signature · 15 lines
Jaegeuk Kim



------------------------------------------------------------------------------
"Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
Instantly run your Selenium tests across 300+ browser/OS combos.
Get unparalleled scalability from the best Selenium testing platform available
Simple to use. Nothing to install. Get started now for free."
http://p.sf.net/sfu/SauceLabs

_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

------------------------------------------------------------------------------
"Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free."
http://p.sf.net/sfu/SauceLabs
_______________________________________________
Linux-f2fs-devel mailing list [email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

author
#3 lore raw

Hi changman,

Quoted 46 lines

-----Original Message-----
From: Changman Lee [mailto:[email protected]]
Sent: Friday, May 23, 2014 1:14 PM
To: Jaegeuk Kim
Cc: Chao Yu; [email protected]; [email protected]; [email protected]
Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages

Quoted 36 lines · Jaegeuk Kim

Hi Chao,

2014-05-16 (금), 17:14 +0800, Chao Yu:

Quoted 33 lines

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +0 -0
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
Quoted 14 lines
Quoted 11 lines

fs/f2fs/node.c int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page) · line 1667

Quoted 11 lines
fs/f2fs/node.c +3 -2
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;

How about use sbi->meta_inode instead of bd_inode, then we can do caching summary pages for further i/o.

In my understanding, In ra_sum_pages() we readahead node pages in NODE segment, then we could padding current summary caching with nid of node page's footer. So we should not cache this readaheaded pages in meta_inode's mapping. Do I miss something?

Regards

Quoted 132 lines
Quoted 8 lines

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

Quoted 8 lines
fs/f2fs/node.c +2 -0
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

*pages,

Quoted 123 lines

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, · line 1681

Quoted 12 lines
fs/f2fs/node.c +2 -5
 	for (; page_idx < start + nrpages; page_idx++) {
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);

IMO, we don't need to do like this.
Instead,

	for() {
		page = grab_cache_page();
		if (!page)
			break;
		page[page_idx] = page;
		f2fs_submit_page_mbio(sbi, page, &fio);
	}
	f2fs_submit_merged_bio(sbi, META, READ);
	return page_idx - start;

Afterwards, in restore_node_summry(),

	lock_page() will wait the end_io for read.
	...
	f2fs_put_page(pages[index], 1);

Thanks,

Quoted 64 lines
fs/f2fs/node.c +17 -12
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:

fs/f2fs/node.c int restore_node_summary(struct f2fs_sb_info *sbi, · line 1744

Quoted 10 lines
fs/f2fs/node.c +4 -2
-			list_del(&page->lru);
-			__free_pages(page, 0);
+			page_cache_release(pages[index]);
 		}
+
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }

--
Jaegeuk Kim

------------------------------------------------------------------------------
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#4 lore raw
Quoted 63 lines · Chao Yu

Hi changman,

Quoted 46 lines

-----Original Message-----
From: Changman Lee [mailto:[email protected]]
Sent: Friday, May 23, 2014 1:14 PM
To: Jaegeuk Kim
Cc: Chao Yu; [email protected]; [email protected]; [email protected]
Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages

Quoted 36 lines · Jaegeuk Kim

Hi Chao,

2014-05-16 (금), 17:14 +0800, Chao Yu:

Quoted 33 lines

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +0 -0
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
Quoted 14 lines
Quoted 11 lines

fs/f2fs/node.c int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page) · line 1667

Quoted 11 lines
fs/f2fs/node.c +3 -2
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;

How about use sbi->meta_inode instead of bd_inode, then we can do caching summary pages for further i/o.

Quoted 7 lines

In my understanding, In ra_sum_pages() we readahead node pages in NODE segment, then we could padding current summary caching with nid of node page's footer. So we should not cache this readaheaded pages in meta_inode's mapping. Do I miss something?

Regards

Sorry, you're right. Forget about caching. I've confused ra_sum_pages with summary segments.

Quoted 128 lines
Quoted 128 lines
Quoted 8 lines

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

Quoted 8 lines
fs/f2fs/node.c +2 -0
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

*pages,

Quoted 118 lines

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, · line 1681

Quoted 12 lines
fs/f2fs/node.c +2 -5
 	for (; page_idx < start + nrpages; page_idx++) {
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);

IMO, we don't need to do like this.
Instead,

	for() {
		page = grab_cache_page();
		if (!page)
			break;
		page[page_idx] = page;
		f2fs_submit_page_mbio(sbi, page, &fio);
	}
	f2fs_submit_merged_bio(sbi, META, READ);
	return page_idx - start;

Afterwards, in restore_node_summry(),

	lock_page() will wait the end_io for read.
	...
	f2fs_put_page(pages[index], 1);

Thanks,

Quoted 64 lines
fs/f2fs/node.c +17 -12
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:

fs/f2fs/node.c int restore_node_summary(struct f2fs_sb_info *sbi, · line 1744

Quoted 10 lines
fs/f2fs/node.c +4 -2
-			list_del(&page->lru);
-			__free_pages(page, 0);
+			page_cache_release(pages[index]);
 		}
+
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }

--
Jaegeuk Kim

------------------------------------------------------------------------------
"Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free."
http://p.sf.net/sfu/SauceLabs

Quoted 4 lines
Quoted 4 lines
Quoted 4 lines

_______________________________________________
Linux-f2fs-devel mailing list
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https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

------------------------------------------------------------------------------
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author
#5 lore raw
In reply to Jaegeuk Kim

Hi Kim,

Quoted 79 lines

-----Original Message-----
From: Jaegeuk Kim [mailto:[email protected]]
Sent: Wednesday, May 21, 2014 11:37 AM
To: Chao Yu
Cc: Jaegeuk Kim; [email protected]; [email protected]; [email protected]
Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid crash when trace f2fs_submit_page_mbio event in ra_sum_pages

Hi Chao,

2014-05-16 (금), 17:14 +0800, Chao Yu:

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

Quoted 51 lines

Previously we allocate pages with no mapping in ra_sum_pages(), so we may encounter a crash in event trace of f2fs_submit_page_mbio where we access mapping data of the page.

We'd better allocate pages in bd_inode mapping and invalidate these pages after we restore data from pages. It could avoid crash in above scenario.

Call Trace:
 [<f1031630>] ? ftrace_raw_event_f2fs_write_checkpoint+0x80/0x80 [f2fs]
 [<f10377bb>] f2fs_submit_page_mbio+0x1cb/0x200 [f2fs]
 [<f103c5da>] restore_node_summary+0x13a/0x280 [f2fs]
 [<f103e22d>] build_curseg+0x2bd/0x620 [f2fs]
 [<f104043b>] build_segment_manager+0x1cb/0x920 [f2fs]
 [<f1032c85>] f2fs_fill_super+0x535/0x8e0 [f2fs]
 [<c115b66a>] mount_bdev+0x16a/0x1a0
 [<f102f63f>] f2fs_mount+0x1f/0x30 [f2fs]
 [<c115c096>] mount_fs+0x36/0x170
 [<c1173635>] vfs_kern_mount+0x55/0xe0
 [<c1175388>] do_mount+0x1e8/0x900
 [<c1175d72>] SyS_mount+0x82/0xc0
 [<c16059cc>] sysenter_do_call+0x12/0x22
Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/node.c |   49 ++++++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 21 deletions(-)
fs/f2fs/node.c +5 -2
index 3d60d3d..b5cd814 100644
@@ -1658,13 +1658,16 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
 
 /*
  * ra_sum_pages() merge contiguous pages into one bio and submit.
- * these pre-readed pages are linked in pages list.
+ * these pre-readed pages are alloced in bd_inode's mapping tree.
  */
-static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages,
+static int ra_sum_pages(struct f2fs_sb_info *sbi, struct page **pages,
 				int start, int nrpages)
 {
 	struct page *page;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
+	struct address_space *mapping = inode->i_mapping;
 	int page_idx = start;
+	int alloced, readed;
 	struct f2fs_io_info fio = {
 		.type = META,
 		.rw = READ_SYNC | REQ_META | REQ_PRIO

@@ -1672,21 +1675,23 @@ static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head

*pages,

fs/f2fs/node.c static int ra_sum_pages(struct f2fs_sb_info *sbi, struct list_head *pages, · line 1681

Quoted 12 lines
fs/f2fs/node.c +2 -5
 	for (; page_idx < start + nrpages; page_idx++) {
 		/* alloc temporal page for read node summary info*/
-		page = alloc_page(GFP_F2FS_ZERO);
+		page = grab_cache_page(mapping, page_idx);
 		if (!page)
 			break;
-
-		lock_page(page);
-		page->index = page_idx;
-		list_add_tail(&page->lru, pages);
+		page_cache_release(page);

IMO, we don't need to do like this.
Instead,

Quoted 9 lines
	for() {
		page = grab_cache_page();
		if (!page)
			break;
		page[page_idx] = page;
		f2fs_submit_page_mbio(sbi, page, &fio);
	}
	f2fs_submit_merged_bio(sbi, META, READ);
	return page_idx - start;

Agreed, it helps to remove a lot of redundant code here. Thanks!

Quoted 77 lines

Afterwards, in restore_node_summry(),

	lock_page() will wait the end_io for read.
	...
	f2fs_put_page(pages[index], 1);

Thanks,

Quoted 69 lines
fs/f2fs/node.c +19 -14
 	}
 
-	list_for_each_entry(page, pages, lru)
-		f2fs_submit_page_mbio(sbi, page, page->index, &fio);
+	alloced = page_idx - start;
+	readed = find_get_pages_contig(mapping, start, alloced, pages);
+	BUG_ON(alloced != readed);
+
+	for (page_idx = 0; page_idx < readed; page_idx++)
+		f2fs_submit_page_mbio(sbi, pages[page_idx],
+					pages[page_idx]->index, &fio);
 
 	f2fs_submit_merged_bio(sbi, META, READ);
 
-	return page_idx - start;
+	return readed;
 }
 
 int restore_node_summary(struct f2fs_sb_info *sbi,

@@ -1694,11 +1699,11 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_node *rn;
 	struct f2fs_summary *sum_entry;
-	struct page *page, *tmp;
+	struct inode *inode = sbi->sb->s_bdev->bd_inode;
 	block_t addr;
 	int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
-	int i, last_offset, nrpages, err = 0;
-	LIST_HEAD(page_list);
+	struct page *pages[bio_blocks];
+	int i, index, last_offset, nrpages, err = 0;
 
 	/* scan the node segment */
 	last_offset = sbi->blocks_per_seg;

@@ -1709,29 +1714,31 @@ int restore_node_summary(struct f2fs_sb_info *sbi,
 		nrpages = min(last_offset - i, bio_blocks);
 
 		/* read ahead node pages */
-		nrpages = ra_sum_pages(sbi, &page_list, addr, nrpages);
+		nrpages = ra_sum_pages(sbi, pages, addr, nrpages);
 		if (!nrpages)
 			return -ENOMEM;
 
-		list_for_each_entry_safe(page, tmp, &page_list, lru) {
+		for (index = 0; index < nrpages; index++) {
 			if (err)
 				goto skip;
 
-			lock_page(page);
-			if (unlikely(!PageUptodate(page))) {
+			lock_page(pages[index]);
+			if (unlikely(!PageUptodate(pages[index]))) {
 				err = -EIO;
 			} else {
-				rn = F2FS_NODE(page);
+				rn = F2FS_NODE(pages[index]);
 				sum_entry->nid = rn->footer.nid;
 				sum_entry->version = 0;
 				sum_entry->ofs_in_node = 0;
 				sum_entry++;
 			}
-			unlock_page(page);
+			unlock_page(pages[index]);
 skip:
-			list_del(&page->lru);
-			__free_pages(page, 0);
+			page_cache_release(pages[index]);
 		}
+
Quoted 8 lines

fs/f2fs/node.c int restore_node_summary(struct f2fs_sb_info *sbi, · line 1744

Quoted 5 lines
fs/f2fs/node.c +2 -0
+		invalidate_mapping_pages(inode->i_mapping, addr,
+							addr + nrpages);
 	}
 	return err;
 }

--
Jaegeuk Kim

------------------------------------------------------------------------------
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