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.

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 44736cb..fc89e91 100644 (file)
--- 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
@@ -624,38 +611,6 @@ 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 0543cdf..b53acca 100644 (file)
--- 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 2c5f9e5..4657143 100644 (file)
--- 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 a7749c1..bd21535 100644 (file)
--- 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 21e09fb..26e69e4 100644 (file)
--- 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 dfa09a2..a1726a8 100644 (file)
--- 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 2c9e26a..f438497 100644 (file)
--- 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 b52f084..2619d94 100644 (file)
--- 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;
 }