With dax we cannot deal with readpage() etc. So, we create a funciton callback to perform the file data comparison and pass it to generic_remap_file_range_prep() so it can use iomap-based functions.
This may not be the best way to solve this. Suggestions welcome. Signed-off-by: Goldwyn Rodrigues <[email protected]> Signed-off-by: Shiyang Ruan <[email protected]> --- fs/btrfs/reflink.c | 3 +- fs/dax.c | 67 ++++++++++++++++++++++++++++++++++++++++++++ fs/ocfs2/file.c | 2 +- fs/read_write.c | 11 ++++---- fs/xfs/xfs_reflink.c | 2 +- include/linux/dax.h | 5 ++++ include/linux/fs.h | 9 +++++- 7 files changed, 90 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c index 040009d1cc31..d0412bc338da 100644 --- a/fs/btrfs/reflink.c +++ b/fs/btrfs/reflink.c @@ -765,7 +765,8 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, return ret; return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - len, remap_flags); + len, remap_flags, + vfs_dedupe_file_range_compare); } loff_t btrfs_remap_file_range(struct file *src_file, loff_t off, diff --git a/fs/dax.c b/fs/dax.c index 28b8e23b11ac..80a9946fd25a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -30,6 +30,8 @@ #define CREATE_TRACE_POINTS #include <trace/events/fs_dax.h> +#define MIN(a, b) (((a) < (b)) ? (a) : (b)) + static inline unsigned int pe_order(enum page_entry_size pe_size) { if (pe_size == PE_SIZE_PTE) @@ -1874,3 +1876,68 @@ 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); + +int dax_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) +{ + void *saddr, *daddr; + struct iomap smap = { 0 }; + struct iomap dmap = { 0 }; + bool same = false; + loff_t cmp_len; + int id, ret = 0; + + id = dax_read_lock(); + while (len) { + ret = ops->iomap_begin(src, srcoff, len, 0, &smap, NULL); + if (ret < 0) + goto out_src; + cmp_len = MIN(len, smap.offset + smap.length - srcoff); + + ret = ops->iomap_begin(dest, destoff, cmp_len, 0, &dmap, NULL); + if (ret < 0) + goto out_dest; + cmp_len = MIN(cmp_len, dmap.offset + dmap.length - destoff); + + if (smap.type == IOMAP_HOLE && dmap.type == IOMAP_HOLE) + goto next; + + if (smap.type == IOMAP_HOLE || dmap.type == IOMAP_HOLE) { + same = false; + goto next; + } + + ret = dax_iomap_direct_access(&smap, srcoff, + ALIGN(srcoff + cmp_len, PAGE_SIZE), NULL, &saddr); + if (ret < 0) + goto out_dest; + + ret = dax_iomap_direct_access(&dmap, destoff, + ALIGN(destoff + cmp_len, PAGE_SIZE), NULL, &daddr); + if (ret < 0) + goto out_dest; + + same = !memcmp(saddr, daddr, cmp_len); + if (!same) + break; +next: + len -= cmp_len; + srcoff += cmp_len; + destoff += cmp_len; +out_dest: + if (ops->iomap_end) + ops->iomap_end(dest, destoff, cmp_len, 0, 0, &dmap); +out_src: + if (ops->iomap_end) + ops->iomap_end(src, srcoff, len, 0, 0, &smap); + + if (ret < 0) + goto out; + } + *is_same = same; +out: + dax_read_unlock(id); + return ret; +} +EXPORT_SYMBOL_GPL(dax_file_range_compare); diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 85979e2214b3..9d101f129d16 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2591,7 +2591,7 @@ static loff_t ocfs2_remap_file_range(struct file *file_in, loff_t pos_in, goto out_unlock; ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - &len, remap_flags); + &len, remap_flags, vfs_dedupe_file_range_compare); if (ret < 0 || len == 0) goto out_unlock; diff --git a/fs/read_write.c b/fs/read_write.c index 4fb797822567..2974a624f232 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1927,7 +1927,7 @@ 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, +int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, loff_t destoff, loff_t len, bool *is_same) { @@ -2008,6 +2008,7 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, out_error: return error; } +EXPORT_SYMBOL_GPL(vfs_dedupe_file_range_compare); /* * Check that the two inodes are eligible for cloning, the ranges make @@ -2019,7 +2020,8 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, */ 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) + loff_t *len, unsigned int remap_flags, + compare_range_t compare) { struct inode *inode_in = file_inode(file_in); struct inode *inode_out = file_inode(file_out); @@ -2078,9 +2080,8 @@ 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); + ret = (*compare)(inode_in, pos_in, + inode_out, pos_out, *len, &is_same); if (ret) return ret; if (!is_same) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 107bf2a2f344..792217cd1e64 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1338,7 +1338,7 @@ xfs_reflink_remap_prep( goto out_unlock; ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - len, remap_flags); + len, remap_flags, vfs_dedupe_file_range_compare); if (ret < 0 || *len == 0) goto out_unlock; diff --git a/include/linux/dax.h b/include/linux/dax.h index d6d9f4b721bc..607e21933928 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -223,6 +223,11 @@ int dax_invalidate_mapping_entry_sync(struct address_space *mapping, pgoff_t index); int dax_iomap_zero(loff_t pos, unsigned offset, unsigned size, struct iomap *iomap); +int dax_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); + static inline bool dax_mapping(struct address_space *mapping) { return mapping->host && IS_DAX(mapping->host); diff --git a/include/linux/fs.h b/include/linux/fs.h index 81de3d2739b9..c2d985295db5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1924,13 +1924,20 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, unsigned long, loff_t *, rwf_t); extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, loff_t, size_t, unsigned int); +extern int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, + struct inode *dest, loff_t destoff, + loff_t len, bool *is_same); +typedef int (*compare_range_t)(struct inode *src, loff_t srcpos, + struct inode *dest, loff_t destpos, + loff_t len, bool *is_same); extern ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, size_t len, unsigned int flags); extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t *count, - unsigned int remap_flags); + unsigned int remap_flags, + compare_range_t cmp); extern loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t len, unsigned int remap_flags); -- 2.27.0
