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authorDan Williams <dan.j.williams@intel.com>2021-09-08 15:58:13 -0700
committerDan Williams <dan.j.williams@intel.com>2021-09-08 15:58:13 -0700
commit3fc3725357414636d91be1558ce8b14f228b4bda (patch)
treee16d052bfac4a5c2da1c9a16cb871e263bfeca3e
parent32b2397c1e56f33b0b1881def965bb89bd12f448 (diff)
parentbdd3c50d83bf7f6acc869b48d02670d19030ae03 (diff)
Merge branch 'for-5.15/fsdax-cleanups' into for-5.15/libnvdimm
Include Christoph's rework of the dax_supported() helpers in the v5.15 libnvdimm update. This supports the ongoing dax-reflink enabling effort.
-rw-r--r--drivers/dax/super.c191
-rw-r--r--drivers/md/dm-table.c9
-rw-r--r--drivers/md/dm.c2
-rw-r--r--fs/Kconfig21
-rw-r--r--fs/ext2/super.c3
-rw-r--r--fs/ext4/super.c3
-rw-r--r--fs/xfs/xfs_super.c16
-rw-r--r--include/linux/dax.h41
8 files changed, 117 insertions, 169 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 44736cbd446e..fc89e91beea7 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -17,6 +17,24 @@
#include <linux/fs.h>
#include "dax-private.h"
+/**
+ * struct dax_device - anchor object for dax services
+ * @inode: core vfs
+ * @cdev: optional character interface for "device dax"
+ * @host: optional name for lookups where the device path is not available
+ * @private: dax driver private data
+ * @flags: state and boolean properties
+ */
+struct dax_device {
+ struct hlist_node list;
+ struct inode inode;
+ struct cdev cdev;
+ const char *host;
+ void *private;
+ unsigned long flags;
+ const struct dax_operations *ops;
+};
+
static dev_t dax_devt;
DEFINE_STATIC_SRCU(dax_srcu);
static struct vfsmount *dax_mnt;
@@ -40,6 +58,42 @@ void dax_read_unlock(int id)
}
EXPORT_SYMBOL_GPL(dax_read_unlock);
+static int dax_host_hash(const char *host)
+{
+ return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
+}
+
+/**
+ * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
+ * @host: alternate name for the device registered by a dax driver
+ */
+static struct dax_device *dax_get_by_host(const char *host)
+{
+ struct dax_device *dax_dev, *found = NULL;
+ int hash, id;
+
+ if (!host)
+ return NULL;
+
+ hash = dax_host_hash(host);
+
+ id = dax_read_lock();
+ spin_lock(&dax_host_lock);
+ hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
+ if (!dax_alive(dax_dev)
+ || strcmp(host, dax_dev->host) != 0)
+ continue;
+
+ if (igrab(&dax_dev->inode))
+ found = dax_dev;
+ break;
+ }
+ spin_unlock(&dax_host_lock);
+ dax_read_unlock(id);
+
+ return found;
+}
+
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
@@ -65,15 +119,13 @@ struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
return dax_get_by_host(bdev->bd_disk->disk_name);
}
EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
-#endif
-bool __generic_fsdax_supported(struct dax_device *dax_dev,
+bool generic_fsdax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors)
{
bool dax_enabled = false;
pgoff_t pgoff, pgoff_end;
- char buf[BDEVNAME_SIZE];
void *kaddr, *end_kaddr;
pfn_t pfn, end_pfn;
sector_t last_page;
@@ -81,29 +133,25 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
int err, id;
if (blocksize != PAGE_SIZE) {
- pr_info("%s: error: unsupported blocksize for dax\n",
- bdevname(bdev, buf));
+ pr_info("%pg: error: unsupported blocksize for dax\n", bdev);
return false;
}
if (!dax_dev) {
- pr_debug("%s: error: dax unsupported by block device\n",
- bdevname(bdev, buf));
+ pr_debug("%pg: error: dax unsupported by block device\n", bdev);
return false;
}
err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
if (err) {
- pr_info("%s: error: unaligned partition for dax\n",
- bdevname(bdev, buf));
+ pr_info("%pg: error: unaligned partition for dax\n", bdev);
return false;
}
last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;
err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
if (err) {
- pr_info("%s: error: unaligned partition for dax\n",
- bdevname(bdev, buf));
+ pr_info("%pg: error: unaligned partition for dax\n", bdev);
return false;
}
@@ -112,8 +160,8 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
if (len < 1 || len2 < 1) {
- pr_info("%s: error: dax access failed (%ld)\n",
- bdevname(bdev, buf), len < 1 ? len : len2);
+ pr_info("%pg: error: dax access failed (%ld)\n",
+ bdev, len < 1 ? len : len2);
dax_read_unlock(id);
return false;
}
@@ -147,57 +195,32 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
dax_read_unlock(id);
if (!dax_enabled) {
- pr_info("%s: error: dax support not enabled\n",
- bdevname(bdev, buf));
+ pr_info("%pg: error: dax support not enabled\n", bdev);
return false;
}
return true;
}
-EXPORT_SYMBOL_GPL(__generic_fsdax_supported);
+EXPORT_SYMBOL_GPL(generic_fsdax_supported);
-/**
- * __bdev_dax_supported() - Check if the device supports dax for filesystem
- * @bdev: block device to check
- * @blocksize: The block size of the device
- *
- * This is a library function for filesystems to check if the block device
- * can be mounted with dax option.
- *
- * Return: true if supported, false if unsupported
- */
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+ int blocksize, sector_t start, sector_t len)
{
- struct dax_device *dax_dev;
- struct request_queue *q;
- char buf[BDEVNAME_SIZE];
- bool ret;
+ bool ret = false;
int id;
- q = bdev_get_queue(bdev);
- if (!q || !blk_queue_dax(q)) {
- pr_debug("%s: error: request queue doesn't support dax\n",
- bdevname(bdev, buf));
- return false;
- }
-
- dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
- if (!dax_dev) {
- pr_debug("%s: error: device does not support dax\n",
- bdevname(bdev, buf));
+ if (!dax_dev)
return false;
- }
id = dax_read_lock();
- ret = dax_supported(dax_dev, bdev, blocksize, 0,
- i_size_read(bdev->bd_inode) / 512);
+ if (dax_alive(dax_dev) && dax_dev->ops->dax_supported)
+ ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize,
+ start, len);
dax_read_unlock(id);
-
- put_dax(dax_dev);
-
return ret;
}
-EXPORT_SYMBOL_GPL(__bdev_dax_supported);
-#endif
+EXPORT_SYMBOL_GPL(dax_supported);
+#endif /* CONFIG_FS_DAX */
+#endif /* CONFIG_BLOCK */
enum dax_device_flags {
/* !alive + rcu grace period == no new operations / mappings */
@@ -208,24 +231,6 @@ enum dax_device_flags {
DAXDEV_SYNC,
};
-/**
- * struct dax_device - anchor object for dax services
- * @inode: core vfs
- * @cdev: optional character interface for "device dax"
- * @host: optional name for lookups where the device path is not available
- * @private: dax driver private data
- * @flags: state and boolean properties
- */
-struct dax_device {
- struct hlist_node list;
- struct inode inode;
- struct cdev cdev;
- const char *host;
- void *private;
- unsigned long flags;
- const struct dax_operations *ops;
-};
-
static ssize_t write_cache_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -323,19 +328,6 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
}
EXPORT_SYMBOL_GPL(dax_direct_access);
-bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
- int blocksize, sector_t start, sector_t len)
-{
- if (!dax_dev)
- return false;
-
- if (!dax_alive(dax_dev))
- return false;
-
- return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
-}
-EXPORT_SYMBOL_GPL(dax_supported);
-
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)
{
@@ -423,11 +415,6 @@ bool dax_alive(struct dax_device *dax_dev)
}
EXPORT_SYMBOL_GPL(dax_alive);
-static int dax_host_hash(const char *host)
-{
- return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
-}
-
/*
* Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring
* that any fault handlers or operations that might have seen
@@ -625,38 +612,6 @@ void put_dax(struct dax_device *dax_dev)
EXPORT_SYMBOL_GPL(put_dax);
/**
- * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
- * @host: alternate name for the device registered by a dax driver
- */
-struct dax_device *dax_get_by_host(const char *host)
-{
- struct dax_device *dax_dev, *found = NULL;
- int hash, id;
-
- if (!host)
- return NULL;
-
- hash = dax_host_hash(host);
-
- id = dax_read_lock();
- spin_lock(&dax_host_lock);
- hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) {
- if (!dax_alive(dax_dev)
- || strcmp(host, dax_dev->host) != 0)
- continue;
-
- if (igrab(&dax_dev->inode))
- found = dax_dev;
- break;
- }
- spin_unlock(&dax_host_lock);
- dax_read_unlock(id);
-
- return found;
-}
-EXPORT_SYMBOL_GPL(dax_get_by_host);
-
-/**
* inode_dax: convert a public inode into its dax_dev
* @inode: An inode with i_cdev pointing to a dax_dev
*
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 0543cdf89e92..b53acca37581 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -809,14 +809,9 @@ EXPORT_SYMBOL_GPL(dm_table_set_type);
int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
- int blocksize = *(int *) data, id;
- bool rc;
+ int blocksize = *(int *) data;
- id = dax_read_lock();
- rc = !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
- dax_read_unlock(id);
-
- return rc;
+ return !dax_supported(dev->dax_dev, dev->bdev, blocksize, start, len);
}
/* Check devices support synchronous DAX */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2c5f9e585211..465714341300 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -650,7 +650,7 @@ static int open_table_device(struct table_device *td, dev_t dev,
}
td->dm_dev.bdev = bdev;
- td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+ td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev);
return 0;
}
diff --git a/fs/Kconfig b/fs/Kconfig
index a7749c126b8e..bd21535a7620 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -43,7 +43,7 @@ source "fs/f2fs/Kconfig"
source "fs/zonefs/Kconfig"
config FS_DAX
- bool "Direct Access (DAX) support"
+ bool "File system based Direct Access (DAX) support"
depends on MMU
depends on !(ARM || MIPS || SPARC)
select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED)
@@ -53,8 +53,23 @@ config FS_DAX
Direct Access (DAX) can be used on memory-backed block devices.
If the block device supports DAX and the filesystem supports DAX,
then you can avoid using the pagecache to buffer I/Os. Turning
- on this option will compile in support for DAX; you will need to
- mount the filesystem using the -o dax option.
+ on this option will compile in support for DAX.
+
+ For a DAX device to support file system access it needs to have
+ struct pages. For the nfit based NVDIMMs this can be enabled
+ using the ndctl utility:
+
+ # ndctl create-namespace --force --reconfig=namespace0.0 \
+ --mode=fsdax --map=mem
+
+ See the 'create-namespace' man page for details on the overhead of
+ --map=mem:
+ https://docs.pmem.io/ndctl-user-guide/ndctl-man-pages/ndctl-create-namespace
+
+ For ndctl to work CONFIG_DEV_DAX needs to be enabled as well. For most
+ file systems DAX support needs to be manually enabled globally or
+ per-inode using a mount option as well. See the file documentation in
+ Documentation/filesystems/dax.rst for details.
If you do not have a block device that is capable of using this,
or if unsure, say N. Saying Y will increase the size of the kernel
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 21e09fbaa46f..26e69e48d7e0 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -949,7 +949,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
if (test_opt(sb, DAX)) {
- if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
+ if (!dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
+ bdev_nr_sectors(sb->s_bdev))) {
ext2_msg(sb, KERN_ERR,
"DAX unsupported by block device. Turning off DAX.");
clear_opt(sbi->s_mount_opt, DAX);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dfa09a277b56..a1726a8debce 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4435,7 +4435,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto failed_mount;
}
- if (bdev_dax_supported(sb->s_bdev, blocksize))
+ if (dax_supported(dax_dev, sb->s_bdev, blocksize, 0,
+ bdev_nr_sectors(sb->s_bdev)))
set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 2c9e26a44546..f4384974e52a 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -314,6 +314,15 @@ xfs_set_inode_alloc(
return (mp->m_flags & XFS_MOUNT_32BITINODES) ? maxagi : agcount;
}
+static bool
+xfs_buftarg_is_dax(
+ struct super_block *sb,
+ struct xfs_buftarg *bt)
+{
+ return dax_supported(bt->bt_daxdev, bt->bt_bdev, sb->s_blocksize, 0,
+ bdev_nr_sectors(bt->bt_bdev));
+}
+
STATIC int
xfs_blkdev_get(
xfs_mount_t *mp,
@@ -1549,11 +1558,10 @@ xfs_fs_fill_super(
xfs_warn(mp,
"DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
- datadev_is_dax = bdev_dax_supported(mp->m_ddev_targp->bt_bdev,
- sb->s_blocksize);
+ datadev_is_dax = xfs_buftarg_is_dax(sb, mp->m_ddev_targp);
if (mp->m_rtdev_targp)
- rtdev_is_dax = bdev_dax_supported(
- mp->m_rtdev_targp->bt_bdev, sb->s_blocksize);
+ rtdev_is_dax = xfs_buftarg_is_dax(sb,
+ mp->m_rtdev_targp);
if (!rtdev_is_dax && !datadev_is_dax) {
xfs_alert(mp,
"DAX unsupported by block device. Turning off DAX.");
diff --git a/include/linux/dax.h b/include/linux/dax.h
index b52f084aa643..2619d94c308d 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -41,7 +41,6 @@ struct dax_operations {
extern struct attribute_group dax_attribute_group;
#if IS_ENABLED(CONFIG_DAX)
-struct dax_device *dax_get_by_host(const char *host);
struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops, unsigned long flags);
void put_dax(struct dax_device *dax_dev);
@@ -58,8 +57,6 @@ static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
__set_dax_synchronous(dax_dev);
}
-bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
- int blocksize, sector_t start, sector_t len);
/*
* Check if given mapping is supported by the file / underlying device.
*/
@@ -73,10 +70,6 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
return dax_synchronous(dax_dev);
}
#else
-static inline struct dax_device *dax_get_by_host(const char *host)
-{
- return NULL;
-}
static inline struct dax_device *alloc_dax(void *private, const char *host,
const struct dax_operations *ops, unsigned long flags)
{
@@ -106,12 +99,6 @@ static inline bool dax_synchronous(struct dax_device *dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
-static inline bool dax_supported(struct dax_device *dax_dev,
- struct block_device *bdev, int blocksize, sector_t start,
- sector_t len)
-{
- return false;
-}
static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct dax_device *dax_dev)
{
@@ -122,22 +109,12 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
struct writeback_control;
int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
#if IS_ENABLED(CONFIG_FS_DAX)
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize);
-static inline bool bdev_dax_supported(struct block_device *bdev, int blocksize)
-{
- return __bdev_dax_supported(bdev, blocksize);
-}
-
-bool __generic_fsdax_supported(struct dax_device *dax_dev,
+bool generic_fsdax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
sector_t sectors);
-static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
- struct block_device *bdev, int blocksize, sector_t start,
- sector_t sectors)
-{
- return __generic_fsdax_supported(dax_dev, bdev, blocksize, start,
- sectors);
-}
+
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
+ int blocksize, sector_t start, sector_t len);
static inline void fs_put_dax(struct dax_device *dax_dev)
{
@@ -153,15 +130,11 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t st
dax_entry_t dax_lock_page(struct page *page);
void dax_unlock_page(struct page *page, dax_entry_t cookie);
#else
-static inline bool bdev_dax_supported(struct block_device *bdev,
- int blocksize)
-{
- return false;
-}
+#define generic_fsdax_supported NULL
-static inline bool generic_fsdax_supported(struct dax_device *dax_dev,
+static inline bool dax_supported(struct dax_device *dax_dev,
struct block_device *bdev, int blocksize, sector_t start,
- sector_t sectors)
+ sector_t len)
{
return false;
}