[PATCH 2/9] iomap: move the swapfile code into a separate file

Darrick J. Wong
2019-07-15T17:59:53Z

From: Darrick J. Wong <darrick.wong@oracle.com>

Move the swapfile activation code into a separate file so that we can
group related functions in a single file instead of having a single
enormous source file.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/iomap.c | 170 ------------------------------------------------
fs/iomap/Makefile | 4 +
fs/iomap/swapfile.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 184 insertions(+), 170 deletions(-)
create mode 100644 fs/iomap/swapfile.c

diff --git a/fs/iomap.c b/fs/iomap.c
index 217c3e5a13d6..521e90825dbe 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -2000,176 +2000,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
}
EXPORT_SYMBOL_GPL(iomap_dio_rw);

-/* Swapfile activation */
-
-#ifdef CONFIG_SWAP
-struct iomap_swapfile_info {
- struct iomap iomap; /* accumulated iomap */
- struct swap_info_struct *sis;
- uint64_t lowest_ppage; /* lowest physical addr seen (pages) */
- uint64_t highest_ppage; /* highest physical addr seen (pages) */
- unsigned long nr_pages; /* number of pages collected */
- int nr_extents; /* extent count */
-};
-
-/*
- * Collect physical extents for this swap file. Physical extents reported to
- * the swap code must be trimmed to align to a page boundary. The logical
- * offset within the file is irrelevant since the swapfile code maps logical
- * page numbers of the swap device to the physical page-aligned extents.
- */
-static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
-{
- struct iomap *iomap = &isi->iomap;
- unsigned long nr_pages;
- uint64_t first_ppage;
- uint64_t first_ppage_reported;
- uint64_t next_ppage;
- int error;
-
- /*
- * Round the start up and the end down so that the physical
- * extent aligns to a page boundary.
- */
- first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
- next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
- PAGE_SHIFT;
-
- /* Skip too-short physical extents. */
- if (first_ppage >= next_ppage)
- return 0;
- nr_pages = next_ppage - first_ppage;
-
- /*
- * Calculate how much swap space we're adding; the first page contains
- * the swap header and doesn't count. The mm still wants that first
- * page fed to add_swap_extent, however.
- */
- first_ppage_reported = first_ppage;
- if (iomap->offset == 0)
- first_ppage_reported++;
- if (isi->lowest_ppage > first_ppage_reported)
- isi->lowest_ppage = first_ppage_reported;
- if (isi->highest_ppage < (next_ppage - 1))
- isi->highest_ppage = next_ppage - 1;
-
- /* Add extent, set up for the next call. */
- error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage);
- if (error < 0)
- return error;
- isi->nr_extents += error;
- isi->nr_pages += nr_pages;
- return 0;
-}
-
-/*
- * Accumulate iomaps for this swap file. We have to accumulate iomaps because
- * swap only cares about contiguous page-aligned physical extents and makes no
- * distinction between written and unwritten extents.
- */
-static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
- loff_t count, void *data, struct iomap *iomap)
-{
- struct iomap_swapfile_info *isi = data;
- int error;
-
- switch (iomap->type) {
- case IOMAP_MAPPED:
- case IOMAP_UNWRITTEN:
- /* Only real or unwritten extents. */
- break;
- case IOMAP_INLINE:
- /* No inline data. */
- pr_err("swapon: file is inline\n");
- return -EINVAL;
- default:
- pr_err("swapon: file has unallocated extents\n");
- return -EINVAL;
- }
-
- /* No uncommitted metadata or shared blocks. */
- if (iomap->flags & IOMAP_F_DIRTY) {
- pr_err("swapon: file is not committed\n");
- return -EINVAL;
- }
- if (iomap->flags & IOMAP_F_SHARED) {
- pr_err("swapon: file has shared extents\n");
- return -EINVAL;
- }
-
- /* Only one bdev per swap file. */
- if (iomap->bdev != isi->sis->bdev) {
- pr_err("swapon: file is on multiple devices\n");
- return -EINVAL;
- }
-
- if (isi->iomap.length == 0) {
- /* No accumulated extent, so just store it. */
- memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
- } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {
- /* Append this to the accumulated extent. */
- isi->iomap.length += iomap->length;
- } else {
- /* Otherwise, add the retained iomap and store this one. */
- error = iomap_swapfile_add_extent(isi);
- if (error)
- return error;
- memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
- }
- return count;
-}
-
-/*
- * Iterate a swap file's iomaps to construct physical extents that can be
- * passed to the swapfile subsystem.
- */
-int iomap_swapfile_activate(struct swap_info_struct *sis,
- struct file *swap_file, sector_t *pagespan,
- const struct iomap_ops *ops)
-{
- struct iomap_swapfile_info isi = {
- .sis = sis,
- .lowest_ppage = (sector_t)-1ULL,
- };
- struct address_space *mapping = swap_file->f_mapping;
- struct inode *inode = mapping->host;
- loff_t pos = 0;
- loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);
- loff_t ret;
-
- /*
- * Persist all file mapping metadata so that we won't have any
- * IOMAP_F_DIRTY iomaps.
- */
- ret = vfs_fsync(swap_file, 1);
- if (ret)
- return ret;
-
- while (len > 0) {
- ret = iomap_apply(inode, pos, len, IOMAP_REPORT,
- ops, &isi, iomap_swapfile_activate_actor);
- if (ret <= 0)
- return ret;
-
- pos += ret;
- len -= ret;
- }
-
- if (isi.iomap.length) {
- ret = iomap_swapfile_add_extent(&isi);
- if (ret)
- return ret;
- }
-
- *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;
- sis->max = isi.nr_pages;
- sis->pages = isi.nr_pages - 1;
- sis->highest_bit = isi.nr_pages - 1;
- return isi.nr_extents;
-}
-EXPORT_SYMBOL_GPL(iomap_swapfile_activate);
-#endif /* CONFIG_SWAP */
-
static loff_t
iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length,
void *data, struct iomap *iomap)
diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index b778a05acac3..e38061f2b901 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -5,3 +5,7 @@
#

ccflags-y += -I $(srctree)/$(src)/..
+
+obj-$(CONFIG_FS_IOMAP) += iomap.o
+
+iomap-$(CONFIG_SWAP) += swapfile.o
diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c
new file mode 100644
index 000000000000..0bd578b580bb
--- /dev/null
+++ b/fs/iomap/swapfile.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/iomap.h>
+#include <linux/swap.h>
+
+#include "internal.h"
+
+/* Swapfile activation */
+
+struct iomap_swapfile_info {
+ struct iomap iomap; /* accumulated iomap */
+ struct swap_info_struct *sis;
+ uint64_t lowest_ppage; /* lowest physical addr seen (pages) */
+ uint64_t highest_ppage; /* highest physical addr seen (pages) */
+ unsigned long nr_pages; /* number of pages collected */
+ int nr_extents; /* extent count */
+};
+
+/*
+ * Collect physical extents for this swap file. Physical extents reported to
+ * the swap code must be trimmed to align to a page boundary. The logical
+ * offset within the file is irrelevant since the swapfile code maps logical
+ * page numbers of the swap device to the physical page-aligned extents.
+ */
+static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi)
+{
+ struct iomap *iomap = &isi->iomap;
+ unsigned long nr_pages;
+ uint64_t first_ppage;
+ uint64_t first_ppage_reported;
+ uint64_t next_ppage;
+ int error;
+
+ /*
+ * Round the start up and the end down so that the physical
+ * extent aligns to a page boundary.
+ */
+ first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT;
+ next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >>
+ PAGE_SHIFT;
+
+ /* Skip too-short physical extents. */
+ if (first_ppage >= next_ppage)
+ return 0;
+ nr_pages = next_ppage - first_ppage;
+
+ /*
+ * Calculate how much swap space we're adding; the first page contains
+ * the swap header and doesn't count. The mm still wants that first
+ * page fed to add_swap_extent, however.
+ */
+ first_ppage_reported = first_ppage;
+ if (iomap->offset == 0)
+ first_ppage_reported++;
+ if (isi->lowest_ppage > first_ppage_reported)
+ isi->lowest_ppage = first_ppage_reported;
+ if (isi->highest_ppage < (next_ppage - 1))
+ isi->highest_ppage = next_ppage - 1;
+
+ /* Add extent, set up for the next call. */
+ error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage);
+ if (error < 0)
+ return error;
+ isi->nr_extents += error;
+ isi->nr_pages += nr_pages;
+ return 0;
+}
+
+/*
+ * Accumulate iomaps for this swap file. We have to accumulate iomaps because
+ * swap only cares about contiguous page-aligned physical extents and makes no
+ * distinction between written and unwritten extents.
+ */
+static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
+ loff_t count, void *data, struct iomap *iomap)
+{
+ struct iomap_swapfile_info *isi = data;
+ int error;
+
+ switch (iomap->type) {
+ case IOMAP_MAPPED:
+ case IOMAP_UNWRITTEN:
+ /* Only real or unwritten extents. */
+ break;
+ case IOMAP_INLINE:
+ /* No inline data. */
+ pr_err("swapon: file is inline\n");
+ return -EINVAL;
+ default:
+ pr_err("swapon: file has unallocated extents\n");
+ return -EINVAL;
+ }
+
+ /* No uncommitted metadata or shared blocks. */
+ if (iomap->flags & IOMAP_F_DIRTY) {
+ pr_err("swapon: file is not committed\n");
+ return -EINVAL;
+ }
+ if (iomap->flags & IOMAP_F_SHARED) {
+ pr_err("swapon: file has shared extents\n");
+ return -EINVAL;
+ }
+
+ /* Only one bdev per swap file. */
+ if (iomap->bdev != isi->sis->bdev) {
+ pr_err("swapon: file is on multiple devices\n");
+ return -EINVAL;
+ }
+
+ if (isi->iomap.length == 0) {
+ /* No accumulated extent, so just store it. */
+ memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
+ } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) {
+ /* Append this to the accumulated extent. */
+ isi->iomap.length += iomap->length;
+ } else {
+ /* Otherwise, add the retained iomap and store this one. */
+ error = iomap_swapfile_add_extent(isi);
+ if (error)
+ return error;
+ memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
+ }
+ return count;
+}
+
+/*
+ * Iterate a swap file's iomaps to construct physical extents that can be
+ * passed to the swapfile subsystem.
+ */
+int iomap_swapfile_activate(struct swap_info_struct *sis,
+ struct file *swap_file, sector_t *pagespan,
+ const struct iomap_ops *ops)
+{
+ struct iomap_swapfile_info isi = {
+ .sis = sis,
+ .lowest_ppage = (sector_t)-1ULL,
+ };
+ struct address_space *mapping = swap_file->f_mapping;
+ struct inode *inode = mapping->host;
+ loff_t pos = 0;
+ loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE);
+ loff_t ret;
+
+ /*
+ * Persist all file mapping metadata so that we won't have any
+ * IOMAP_F_DIRTY iomaps.
+ */
+ ret = vfs_fsync(swap_file, 1);
+ if (ret)
+ return ret;
+
+ while (len > 0) {
+ ret = iomap_apply(inode, pos, len, IOMAP_REPORT,
+ ops, &isi, iomap_swapfile_activate_actor);
+ if (ret <= 0)
+ return ret;
+
+ pos += ret;
+ len -= ret;
+ }
+
+ if (isi.iomap.length) {
+ ret = iomap_swapfile_add_extent(&isi);
+ if (ret)
+ return ret;
+ }
+
+ *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage;
+ sis->max = isi.nr_pages;
+ sis->pages = isi.nr_pages - 1;
+ sis->highest_bit = isi.nr_pages - 1;
+ return isi.nr_extents;
+}
+EXPORT_SYMBOL_GPL(iomap_swapfile_activate);