diff mbox

[1/2] fs: Add iomap_swap_activate

Message ID 20180420220815.44160-2-cyberax@amazon.com (mailing list archive)
State Superseded
Headers show

Commit Message

Aleksei Besogonov April 20, 2018, 10:08 p.m. UTC 
This commit adds an alternative to generic_swapfile_activate function
based on iomap family. The major driver for this is swap file support
on XFS, currently it doesn't work on files with holes due to deficiencies
in the old bmap() interface that is used by generic_swapfile_activate.
---
 fs/iomap.c            | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/iomap.h |  5 +++
 mm/swapfile.c         |  1 +
 3 files changed, 93 insertions(+)

Comments

kernel test robot April 25, 2018, 9:34 p.m. UTC | #1 
Hi Aleksei,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17-rc2 next-20180424]
[cannot apply to dgc-xfs/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Aleksei-Besogonov/fs-Add-iomap_swap_activate/20180423-061348
config: x86_64-randconfig-s4-04260252 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   fs/iomap.c: In function 'iomap_swap_map':
>> fs/iomap.c:1130:8: error: implicit declaration of function 'add_swap_extent'; did you mean '__swap_count'? [-Werror=implicit-function-declaration]
     ret = add_swap_extent(ctx->sis, ctx->page_no, num_pages, disk_pos);
           ^~~~~~~~~~~~~~~
           __swap_count
   cc1: some warnings being treated as errors

vim +1130 fs/iomap.c

  1100	
  1101	static loff_t
  1102	iomap_swap_map(struct inode *inode, loff_t pos, loff_t length,
  1103			void *data, struct iomap *iomap)
  1104	{
  1105		struct iomap_swap_walker_context *ctx = data;
  1106		unsigned int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
  1107		u64 num_pages;
  1108		u64 aligned_address;
  1109		sector_t disk_pos;
  1110		loff_t eff_length;
  1111		loff_t ret;
  1112	
  1113		/*
  1114		 * Swap extents need to be PAGE_SIZE aligned on the disk
  1115		 */
  1116		aligned_address = ALIGN(iomap->addr, PAGE_SIZE);
  1117		eff_length = length - (aligned_address - iomap->addr);
  1118		BUG_ON(eff_length > length);
  1119		disk_pos = aligned_address >> inode->i_blkbits;
  1120	
  1121		if (eff_length < 0)
  1122			return length; /* Continue probing */
  1123	
  1124		num_pages = eff_length / PAGE_SIZE;
  1125	
  1126		/* Can't add blocks less than 1 page */
  1127		if (num_pages == 0)
  1128			return length; /* Continue probing */
  1129	
> 1130		ret = add_swap_extent(ctx->sis, ctx->page_no, num_pages, disk_pos);
  1131		if (ret < 0)
  1132			return ret;
  1133	
  1134		ctx->nr_extents += ret;
  1135		ctx->page_no += num_pages;
  1136		*(ctx->span) += num_pages * blocks_per_page;
  1137	
  1138		return length; /* continue probing */
  1139	}
  1140	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot April 25, 2018, 9:38 p.m. UTC | #2 
Hi Aleksei,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.17-rc2 next-20180424]
[cannot apply to dgc-xfs/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Aleksei-Besogonov/fs-Add-iomap_swap_activate/20180423-061348
config: x86_64-randconfig-s2-04260250 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   fs/iomap.c: In function 'iomap_swap_map':
>> fs/iomap.c:1130:8: error: implicit declaration of function 'add_swap_extent' [-Werror=implicit-function-declaration]
     ret = add_swap_extent(ctx->sis, ctx->page_no, num_pages, disk_pos);
           ^~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/add_swap_extent +1130 fs/iomap.c

  1100	
  1101	static loff_t
  1102	iomap_swap_map(struct inode *inode, loff_t pos, loff_t length,
  1103			void *data, struct iomap *iomap)
  1104	{
  1105		struct iomap_swap_walker_context *ctx = data;
  1106		unsigned int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
  1107		u64 num_pages;
  1108		u64 aligned_address;
  1109		sector_t disk_pos;
  1110		loff_t eff_length;
  1111		loff_t ret;
  1112	
  1113		/*
  1114		 * Swap extents need to be PAGE_SIZE aligned on the disk
  1115		 */
  1116		aligned_address = ALIGN(iomap->addr, PAGE_SIZE);
  1117		eff_length = length - (aligned_address - iomap->addr);
  1118		BUG_ON(eff_length > length);
  1119		disk_pos = aligned_address >> inode->i_blkbits;
  1120	
  1121		if (eff_length < 0)
  1122			return length; /* Continue probing */
  1123	
  1124		num_pages = eff_length / PAGE_SIZE;
  1125	
  1126		/* Can't add blocks less than 1 page */
  1127		if (num_pages == 0)
  1128			return length; /* Continue probing */
  1129	
> 1130		ret = add_swap_extent(ctx->sis, ctx->page_no, num_pages, disk_pos);
  1131		if (ret < 0)
  1132			return ret;
  1133	
  1134		ctx->nr_extents += ret;
  1135		ctx->page_no += num_pages;
  1136		*(ctx->span) += num_pages * blocks_per_page;
  1137	
  1138		return length; /* continue probing */
  1139	}
  1140	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
diff mbox

Patch

diff --git a/fs/iomap.c b/fs/iomap.c
index afd163586aa0..9f0980637dbc 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1089,3 +1089,90 @@  iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(iomap_dio_rw);
+
+struct iomap_swap_walker_context
+{
+    struct swap_info_struct *sis;
+    unsigned int page_no;
+    unsigned int nr_extents;
+    sector_t *span;
+};
+
+static loff_t
+iomap_swap_map(struct inode *inode, loff_t pos, loff_t length,
+		void *data, struct iomap *iomap)
+{
+	struct iomap_swap_walker_context *ctx = data;
+	unsigned int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
+	u64 num_pages;
+	u64 aligned_address;
+	sector_t disk_pos;
+	loff_t eff_length;
+	loff_t ret;
+
+	/*
+	 * Swap extents need to be PAGE_SIZE aligned on the disk
+	 */
+	aligned_address = ALIGN(iomap->addr, PAGE_SIZE);
+	eff_length = length - (aligned_address - iomap->addr);
+	BUG_ON(eff_length > length);
+	disk_pos = aligned_address >> inode->i_blkbits;
+
+	if (eff_length < 0)
+		return length; /* Continue probing */
+
+	num_pages = eff_length / PAGE_SIZE;
+
+	/* Can't add blocks less than 1 page */
+	if (num_pages == 0)
+		return length; /* Continue probing */
+
+	ret = add_swap_extent(ctx->sis, ctx->page_no, num_pages, disk_pos);
+	if (ret < 0)
+		return ret;
+
+	ctx->nr_extents += ret;
+	ctx->page_no += num_pages;
+	*(ctx->span) += num_pages * blocks_per_page;
+
+	return length; /* continue probing */
+}
+
+int
+iomap_swap_activate(struct swap_info_struct *sis, struct file *file,
+		sector_t *span, const struct iomap_ops *ops)
+{
+	struct iomap_swap_walker_context ctx = {
+		.sis = sis,
+		.page_no = 0,
+		.nr_extents = 0,
+		.span = span
+	};
+
+	struct inode * inode = file_inode(file);
+	loff_t len = i_size_read(inode);
+	loff_t pos = 0;
+	loff_t ret = -EINVAL;
+
+	while(len > 0) {
+		ret = iomap_apply(inode, pos, len, IOMAP_REPORT, ops,
+				  &ctx, iomap_swap_map);
+		if (ret <= 0)
+			break;
+
+		pos += ret;
+		len -= ret;
+	}
+
+	if (ret < 0) {
+		pr_err("Failed to activate the swap file\n");
+		return -EINVAL;
+	}
+
+	sis->max = ctx.page_no == 0 ? 1 : ctx.page_no;
+	sis->pages = ctx.page_no;
+	sis->highest_bit = ctx.page_no;
+
+	return ctx.nr_extents;
+}
+EXPORT_SYMBOL_GPL(iomap_swap_activate);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 19a07de28212..a85da0db6c2e 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -10,6 +10,8 @@  struct iov_iter;
 struct kiocb;
 struct vm_area_struct;
 struct vm_fault;
+struct file;
+struct swap_info_struct;
 
 /*
  * Types of block ranges for iomap mappings:
@@ -106,4 +108,7 @@  typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 
+int iomap_swap_activate(struct swap_info_struct *sis, struct file *file,
+			sector_t *span, const struct iomap_ops *ops);
+
 #endif /* LINUX_IOMAP_H */
diff --git a/mm/swapfile.c b/mm/swapfile.c
index c7a33717d079..9e6d3c1a882e 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2381,6 +2381,7 @@  add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
 	list_add_tail(&new_se->list, &sis->first_swap_extent.list);
 	return 1;
 }
+EXPORT_SYMBOL_GPL(add_swap_extent);
 
 /*
  * A `swap extent' is a simple thing which maps a contiguous range of pages