From: Goldwyn Rodrigues <[email protected]> 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]> --- fs/btrfs/ioctl.c | 11 ++++++-- fs/dax.c | 65 ++++++++++++++++++++++++++++++++++++++++++++ fs/ocfs2/file.c | 2 +- fs/read_write.c | 11 ++++---- fs/xfs/xfs_reflink.c | 2 +- include/linux/dax.h | 4 +++ include/linux/fs.h | 8 +++++- 7 files changed, 93 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index cd4e693406a0..8f9c749c4aa6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3936,6 +3936,7 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, bool same_inode = inode_out == inode_in; u64 wb_len; int ret; + compare_range_t cmp; if (!(remap_flags & REMAP_FILE_DEDUP)) { struct btrfs_root *root_out = BTRFS_I(inode_out)->root; @@ -3997,8 +3998,14 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, if (ret < 0) goto out_unlock; - ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - len, remap_flags); + if (IS_DAX(file_inode(file_in)) && IS_DAX(file_inode(file_out))) + cmp = btrfs_dax_file_range_compare; + else + cmp = vfs_dedupe_file_range_compare; + + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, + pos_out, len, remap_flags, cmp); + if (ret < 0 || *len == 0) goto out_unlock; diff --git a/fs/dax.c b/fs/dax.c index 8eb065a1ec51..8111ba93f4d3 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -39,6 +39,8 @@ #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) @@ -1817,3 +1819,66 @@ 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 inline void *iomap_address(struct iomap *iomap, loff_t off, loff_t len) +{ + loff_t start; + void *addr; + start = (get_start_sect(iomap->bdev) << 9) + iomap->addr + + (off - iomap->offset); + dax_direct_access(iomap->dax_dev, PHYS_PFN(start), PHYS_PFN(len), + &addr, NULL); + return addr; +} + +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 s_iomap = {0}; + struct iomap d_iomap = {0}; + bool same = true; + loff_t cmp_len; + int id, ret = 0; + + id = dax_read_lock(); + while (len) { + ret = ops->iomap_begin(src, srcoff, len, 0, &s_iomap, NULL); + if (ret < 0) { + if (ops->iomap_end) + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); + return ret; + } + cmp_len = len; + cmp_len = MIN(len, s_iomap.offset + s_iomap.length - srcoff); + + ret = ops->iomap_begin(dest, destoff, cmp_len, 0, &d_iomap, NULL); + if (ret < 0) { + if (ops->iomap_end) { + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); + ops->iomap_end(dest, destoff, len, ret, 0, &d_iomap); + } + return ret; + } + cmp_len = MIN(cmp_len, d_iomap.offset + d_iomap.length - destoff); + + saddr = iomap_address(&s_iomap, srcoff, cmp_len); + daddr = iomap_address(&d_iomap, destoff, cmp_len); + + same = !memcmp(saddr, daddr, cmp_len); + if (!same) + break; + len -= cmp_len; + srcoff += cmp_len; + destoff += cmp_len; + + if (ops->iomap_end) { + ret = ops->iomap_end(src, srcoff, len, 0, 0, &s_iomap); + ret = ops->iomap_end(dest, destoff, len, 0, 0, &d_iomap); + } + } + dax_read_unlock(id); + *is_same = same; + return ret; +} +EXPORT_SYMBOL_GPL(dax_file_range_compare); diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index d640c5f8a85d..9d470306cfc3 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2558,7 +2558,7 @@ 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 61b43ad7608e..c6283802ef1c 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1778,7 +1778,7 @@ static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset) * 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) { @@ -1845,6 +1845,7 @@ 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 @@ -1856,7 +1857,8 @@ 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); @@ -1915,9 +1917,8 @@ 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 680ae7662a78..68e4257cebb0 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1350,7 +1350,7 @@ 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 0dd316a74a29..1370d39c91b6 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -157,6 +157,10 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); int dax_invalidate_mapping_entry_sync(struct address_space *mapping, pgoff_t index); +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); #ifdef CONFIG_FS_DAX int __dax_zero_page_range(struct block_device *bdev, diff --git a/include/linux/fs.h b/include/linux/fs.h index dd28e7679089..0224503e42ce 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1883,10 +1883,16 @@ 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 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); -- 2.17.0
