Re: [PATCH v5 5/7] fsdax: Dedup file range to use a compare function

With dax we cannot deal with readpage() etc. So, we create a dax comparison funciton which is similar with vfs_dedupe_file_range_compare(). And introduce dax_remap_file_range_prep() for filesystem use. Signed-off-by: Goldwyn Rodrigues <rgoldwyn(a)suse.com&gt; Signed-off-by: Shiyang Ruan <ruansy.fnst(a)fujitsu.com&gt; --- fs/dax.c | 56 +++++++++++++++++++++++++++++++++++++++++++ fs/remap_range.c | 57 +++++++++++++++++++++++++++++++++++++------- fs/xfs/xfs_reflink.c | 8 +++++-- include/linux/dax.h | 4 ++++ include/linux/fs.h | 12 ++++++---- 5 files changed, 123 insertions(+), 14 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index ee9d28a79bfb..dedf1be0155c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1853,3 +1853,59 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, return dax_insert_pfn_mkwrite(vmf, pfn, order); } EXPORT_SYMBOL_GPL(dax_finish_sync_fault); + +static loff_t dax_range_compare_actor(struct inode *ino1, loff_t pos1, + struct inode *ino2, loff_t pos2, loff_t len, void *data, + struct iomap *smap, struct iomap *dmap) +{ + void *saddr, *daddr; + bool *same = data; + int ret; + + if (smap->type == IOMAP_HOLE && dmap->type == IOMAP_HOLE) { + *same = true; + return len; + } + + if (smap->type == IOMAP_HOLE || dmap->type == IOMAP_HOLE) { + *same = false; + return 0; + } + + ret = dax_iomap_direct_access(smap, pos1, ALIGN(pos1 + len, PAGE_SIZE), + &saddr, NULL); + if (ret < 0) + return -EIO; + + ret = dax_iomap_direct_access(dmap, pos2, ALIGN(pos2 + len, PAGE_SIZE), + &daddr, NULL); + if (ret < 0) + return -EIO; + + *same = !memcmp(saddr, daddr, len); + return len; +} + +int dax_dedupe_file_range_compare(struct inode *src, loff_t srcoff, + struct inode *dest, loff_t destoff, loff_t len, bool *is_same, + const struct iomap_ops *ops) +{ + int id, ret = 0; + + id = dax_read_lock(); + while (len) { + ret = iomap_apply2(src, srcoff, dest, destoff, len, 0, ops, + is_same, dax_range_compare_actor); + if (ret < 0 || !*is_same) + goto out; + + len -= ret; + srcoff += ret; + destoff += ret; + } + ret = 0; +out: + dax_read_unlock(id); + return ret; +} +EXPORT_SYMBOL_GPL(dax_dedupe_file_range_compare); diff --git a/fs/remap_range.c b/fs/remap_range.c index e4a5fdd7ad7b..7bc4c8e3aa9f 100644 --- a/fs/remap_range.c +++ b/fs/remap_range.c @@ -14,6 +14,7 @@ #include <linux/compat.h> #include <linux/mount.h> #include <linux/fs.h> +#include <linux/dax.h> #include "internal.h" #include <linux/uaccess.h> @@ -199,9 +200,9 @@ static void vfs_unlock_two_pages(struct page *page1, struct page *page2) * Compare extents of two files to see if they are the same. * Caller must have locked both inodes to prevent write races. */ -static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, - struct inode *dest, loff_t destoff, - loff_t len, bool *is_same) +int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, + struct inode *dest, loff_t destoff, + loff_t len, bool *is_same) { loff_t src_poff; loff_t dest_poff; @@ -280,6 +281,7 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, out_error: return error; } +EXPORT_SYMBOL(vfs_dedupe_file_range_compare); /* * Check that the two inodes are eligible for cloning, the ranges make @@ -289,9 +291,11 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, * If there's an error, then the usual negative error code is returned. * Otherwise returns 0 with *len set to the request length. */ -int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, - struct file *file_out, loff_t pos_out, - loff_t *len, unsigned int remap_flags) +static int +__generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *len, unsigned int remap_flags, + const struct iomap_ops *dax_read_ops) { struct inode *inode_in = file_inode(file_in); struct inode *inode_out = file_inode(file_out); @@ -351,8 +355,17 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, if (remap_flags & REMAP_FILE_DEDUP) { bool is_same = false; - ret = vfs_dedupe_file_range_compare(inode_in, pos_in, - inode_out, pos_out, *len, &is_same); + if (!IS_DAX(inode_in)) + ret = vfs_dedupe_file_range_compare(inode_in, pos_in, + inode_out, pos_out, *len, &is_same); +#ifdef CONFIG_FS_DAX + else if (dax_read_ops) + ret = dax_dedupe_file_range_compare(inode_in, pos_in, + inode_out, pos_out, *len, &is_same, + dax_read_ops); +#endif /* CONFIG_FS_DAX */

+ else + return -EINVAL; if (ret) return ret; if (!is_same) @@ -370,6 +383,34 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, return ret; } + +#ifdef CONFIG_FS_DAX +int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *len, unsigned int remap_flags, + const struct iomap_ops *ops) +{ + return __generic_remap_file_range_prep(file_in, pos_in, file_out, + pos_out, len, remap_flags, ops); +} +#else +int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t *len, unsigned int remap_flags, + const struct iomap_ops *ops) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_FS_DAX */ +EXPORT_SYMBOL(dax_remap_file_range_prep);