Loading fs/Kconfig +3 −0 Original line number Diff line number Diff line Loading @@ -10,6 +10,9 @@ config DCACHE_WORD_ACCESS if BLOCK config FS_IOMAP bool source "fs/ext2/Kconfig" source "fs/ext4/Kconfig" source "fs/jbd2/Kconfig" Loading fs/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -49,6 +49,7 @@ obj-$(CONFIG_COREDUMP) += coredump.o obj-$(CONFIG_SYSCTL) += drop_caches.o obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FS_IOMAP) += iomap.o obj-y += quota/ Loading fs/buffer.c +71 −5 Original line number Diff line number Diff line Loading @@ -21,6 +21,7 @@ #include <linux/kernel.h> #include <linux/syscalls.h> #include <linux/fs.h> #include <linux/iomap.h> #include <linux/mm.h> #include <linux/percpu.h> #include <linux/slab.h> Loading Loading @@ -1891,8 +1892,62 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) } EXPORT_SYMBOL(page_zero_new_buffers); int __block_write_begin(struct page *page, loff_t pos, unsigned len, get_block_t *get_block) static void iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh, struct iomap *iomap) { loff_t offset = block << inode->i_blkbits; bh->b_bdev = iomap->bdev; /* * Block points to offset in file we need to map, iomap contains * the offset at which the map starts. If the map ends before the * current block, then do not map the buffer and let the caller * handle it. */ BUG_ON(offset >= iomap->offset + iomap->length); switch (iomap->type) { case IOMAP_HOLE: /* * If the buffer is not up to date or beyond the current EOF, * we need to mark it as new to ensure sub-block zeroing is * executed if necessary. */ if (!buffer_uptodate(bh) || (offset >= i_size_read(inode))) set_buffer_new(bh); break; case IOMAP_DELALLOC: if (!buffer_uptodate(bh) || (offset >= i_size_read(inode))) set_buffer_new(bh); set_buffer_uptodate(bh); set_buffer_mapped(bh); set_buffer_delay(bh); break; case IOMAP_UNWRITTEN: /* * For unwritten regions, we always need to ensure that * sub-block writes cause the regions in the block we are not * writing to are zeroed. Set the buffer as new to ensure this. */ set_buffer_new(bh); set_buffer_unwritten(bh); /* FALLTHRU */ case IOMAP_MAPPED: if (offset >= i_size_read(inode)) set_buffer_new(bh); bh->b_blocknr = (iomap->blkno >> (inode->i_blkbits - 9)) + ((offset - iomap->offset) >> inode->i_blkbits); set_buffer_mapped(bh); break; } } int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap) { unsigned from = pos & (PAGE_SIZE - 1); unsigned to = from + len; Loading Loading @@ -1928,9 +1983,14 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len, clear_buffer_new(bh); if (!buffer_mapped(bh)) { WARN_ON(bh->b_size != blocksize); if (get_block) { err = get_block(inode, block, bh, 1); if (err) break; } else { iomap_to_bh(inode, block, bh, iomap); } if (buffer_new(bh)) { unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); Loading Loading @@ -1971,6 +2031,12 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len, page_zero_new_buffers(page, from, to); return err; } int __block_write_begin(struct page *page, loff_t pos, unsigned len, get_block_t *get_block) { return __block_write_begin_int(page, pos, len, get_block, NULL); } EXPORT_SYMBOL(__block_write_begin); static int __block_commit_write(struct inode *inode, struct page *page, Loading fs/internal.h +3 −0 Original line number Diff line number Diff line Loading @@ -11,6 +11,7 @@ struct super_block; struct file_system_type; struct iomap; struct linux_binprm; struct path; struct mount; Loading Loading @@ -39,6 +40,8 @@ static inline int __sync_blockdev(struct block_device *bdev, int wait) * buffer.c */ extern void guard_bio_eod(int rw, struct bio *bio); extern int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap); /* * char_dev.c Loading fs/iomap.c 0 → 100644 +497 −0 Original line number Diff line number Diff line /* * Copyright (C) 2010 Red Hat, Inc. * Copyright (c) 2016 Christoph Hellwig. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ #include <linux/module.h> #include <linux/compiler.h> #include <linux/fs.h> #include <linux/iomap.h> #include <linux/uaccess.h> #include <linux/gfp.h> #include <linux/mm.h> #include <linux/swap.h> #include <linux/pagemap.h> #include <linux/file.h> #include <linux/uio.h> #include <linux/backing-dev.h> #include <linux/buffer_head.h> #include <linux/dax.h> #include "internal.h" typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, void *data, struct iomap *iomap); /* * Execute a iomap write on a segment of the mapping that spans a * contiguous range of pages that have identical block mapping state. * * This avoids the need to map pages individually, do individual allocations * for each page and most importantly avoid the need for filesystem specific * locking per page. Instead, all the operations are amortised over the entire * range of pages. It is assumed that the filesystems will lock whatever * resources they require in the iomap_begin call, and release them in the * iomap_end call. */ static loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, struct iomap_ops *ops, void *data, iomap_actor_t actor) { struct iomap iomap = { 0 }; loff_t written = 0, ret; /* * Need to map a range from start position for length bytes. This can * span multiple pages - it is only guaranteed to return a range of a * single type of pages (e.g. all into a hole, all mapped or all * unwritten). Failure at this point has nothing to undo. * * If allocation is required for this range, reserve the space now so * that the allocation is guaranteed to succeed later on. Once we copy * the data into the page cache pages, then we cannot fail otherwise we * expose transient stale data. If the reserve fails, we can safely * back out at this point as there is nothing to undo. */ ret = ops->iomap_begin(inode, pos, length, flags, &iomap); if (ret) return ret; if (WARN_ON(iomap.offset > pos)) return -EIO; /* * Cut down the length to the one actually provided by the filesystem, * as it might not be able to give us the whole size that we requested. */ if (iomap.offset + iomap.length < pos + length) length = iomap.offset + iomap.length - pos; /* * Now that we have guaranteed that the space allocation will succeed. * we can do the copy-in page by page without having to worry about * failures exposing transient data. */ written = actor(inode, pos, length, data, &iomap); /* * Now the data has been copied, commit the range we've copied. This * should not fail unless the filesystem has had a fatal error. */ ret = ops->iomap_end(inode, pos, length, written > 0 ? written : 0, flags, &iomap); return written ? written : ret; } static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { loff_t i_size = i_size_read(inode); /* * Only truncate newly allocated pages beyoned EOF, even if the * write started inside the existing inode size. */ if (pos + len > i_size) truncate_pagecache_range(inode, max(pos, i_size), pos + len); } static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, struct page **pagep, struct iomap *iomap) { pgoff_t index = pos >> PAGE_SHIFT; struct page *page; int status = 0; BUG_ON(pos + len > iomap->offset + iomap->length); page = grab_cache_page_write_begin(inode->i_mapping, index, flags); if (!page) return -ENOMEM; status = __block_write_begin_int(page, pos, len, NULL, iomap); if (unlikely(status)) { unlock_page(page); put_page(page); page = NULL; iomap_write_failed(inode, pos, len); } *pagep = page; return status; } static int iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, struct page *page) { int ret; ret = generic_write_end(NULL, inode->i_mapping, pos, len, copied, page, NULL); if (ret < len) iomap_write_failed(inode, pos, len); return ret; } static loff_t iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iov_iter *i = data; long status = 0; ssize_t written = 0; unsigned int flags = AOP_FLAG_NOFS; /* * Copies from kernel address space cannot fail (NFSD is a big user). */ if (!iter_is_iovec(i)) flags |= AOP_FLAG_UNINTERRUPTIBLE; do { struct page *page; unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ offset = (pos & (PAGE_SIZE - 1)); bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_count(i)); again: if (bytes > length) bytes = length; /* * Bring in the user page that we will copy from _first_. * Otherwise there's a nasty deadlock on copying from the * same page as we're writing to, without it being marked * up-to-date. * * Not only is this an optimisation, but it is also required * to check that the address is actually valid, when atomic * usercopies are used, below. */ if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; break; } status = iomap_write_begin(inode, pos, bytes, flags, &page, iomap); if (unlikely(status)) break; if (mapping_writably_mapped(inode->i_mapping)) flush_dcache_page(page); pagefault_disable(); copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); pagefault_enable(); flush_dcache_page(page); mark_page_accessed(page); status = iomap_write_end(inode, pos, bytes, copied, page); if (unlikely(status < 0)) break; copied = status; cond_resched(); iov_iter_advance(i, copied); if (unlikely(copied == 0)) { /* * If we were unable to copy any data at all, we must * fall back to a single segment length write. * * If we didn't fallback here, we could livelock * because not all segments in the iov can be copied at * once without a pagefault. */ bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_single_seg_count(i)); goto again; } pos += copied; written += copied; length -= copied; balance_dirty_pages_ratelimited(inode->i_mapping); } while (iov_iter_count(i) && length); return written ? written : status; } ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops) { struct inode *inode = iocb->ki_filp->f_mapping->host; loff_t pos = iocb->ki_pos, ret = 0, written = 0; while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), IOMAP_WRITE, ops, iter, iomap_write_actor); if (ret <= 0) break; pos += ret; written += ret; } return written ? written : ret; } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { struct page *page; int status; status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_UNINTERRUPTIBLE | AOP_FLAG_NOFS, &page, iomap); if (status) return status; zero_user(page, offset, bytes); mark_page_accessed(page); return iomap_write_end(inode, pos, bytes, bytes, page); } static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { sector_t sector = iomap->blkno + (((pos & ~(PAGE_SIZE - 1)) - iomap->offset) >> 9); return __dax_zero_page_range(iomap->bdev, sector, offset, bytes); } static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, void *data, struct iomap *iomap) { bool *did_zero = data; loff_t written = 0; int status; /* already zeroed? we're done. */ if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) return count; do { unsigned offset, bytes; offset = pos & (PAGE_SIZE - 1); /* Within page */ bytes = min_t(unsigned, PAGE_SIZE - offset, count); if (IS_DAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else status = iomap_zero(inode, pos, offset, bytes, iomap); if (status < 0) return status; pos += bytes; count -= bytes; written += bytes; if (did_zero) *did_zero = true; } while (count > 0); return written; } int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, struct iomap_ops *ops) { loff_t ret; while (len > 0) { ret = iomap_apply(inode, pos, len, IOMAP_ZERO, ops, did_zero, iomap_zero_range_actor); if (ret <= 0) return ret; pos += ret; len -= ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_zero_range); int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, struct iomap_ops *ops) { unsigned blocksize = (1 << inode->i_blkbits); unsigned off = pos & (blocksize - 1); /* Block boundary? Nothing to do */ if (!off) return 0; return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); } EXPORT_SYMBOL_GPL(iomap_truncate_page); static loff_t iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct page *page = data; int ret; ret = __block_write_begin_int(page, pos & ~PAGE_MASK, length, NULL, iomap); if (ret) return ret; block_commit_write(page, 0, length); return length; } int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap_ops *ops) { struct page *page = vmf->page; struct inode *inode = file_inode(vma->vm_file); unsigned long length; loff_t offset, size; ssize_t ret; lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || (page_offset(page) > size)) { /* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; } /* page is wholly or partially inside EOF */ if (((page->index + 1) << PAGE_SHIFT) > size) length = size & ~PAGE_MASK; else length = PAGE_SIZE; offset = page_offset(page); while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_WRITE, ops, page, iomap_page_mkwrite_actor); if (unlikely(ret <= 0)) goto out_unlock; offset += ret; length -= ret; } set_page_dirty(page); wait_for_stable_page(page); return 0; out_unlock: unlock_page(page); return ret; } EXPORT_SYMBOL_GPL(iomap_page_mkwrite); struct fiemap_ctx { struct fiemap_extent_info *fi; struct iomap prev; }; static int iomap_to_fiemap(struct fiemap_extent_info *fi, struct iomap *iomap, u32 flags) { switch (iomap->type) { case IOMAP_HOLE: /* skip holes */ return 0; case IOMAP_DELALLOC: flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN; break; case IOMAP_UNWRITTEN: flags |= FIEMAP_EXTENT_UNWRITTEN; break; case IOMAP_MAPPED: break; } return fiemap_fill_next_extent(fi, iomap->offset, iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0, iomap->length, flags | FIEMAP_EXTENT_MERGED); } static loff_t iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct fiemap_ctx *ctx = data; loff_t ret = length; if (iomap->type == IOMAP_HOLE) return length; ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0); ctx->prev = *iomap; switch (ret) { case 0: /* success */ return length; case 1: /* extent array full */ return 0; default: return ret; } } int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, loff_t start, loff_t len, struct iomap_ops *ops) { struct fiemap_ctx ctx; loff_t ret; memset(&ctx, 0, sizeof(ctx)); ctx.fi = fi; ctx.prev.type = IOMAP_HOLE; ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC); if (ret) return ret; ret = filemap_write_and_wait(inode->i_mapping); if (ret) return ret; while (len > 0) { ret = iomap_apply(inode, start, len, 0, ops, &ctx, iomap_fiemap_actor); if (ret < 0) return ret; if (ret == 0) break; start += ret; len -= ret; } if (ctx.prev.type != IOMAP_HOLE) { ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST); if (ret < 0) return ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_fiemap); Loading
fs/Kconfig +3 −0 Original line number Diff line number Diff line Loading @@ -10,6 +10,9 @@ config DCACHE_WORD_ACCESS if BLOCK config FS_IOMAP bool source "fs/ext2/Kconfig" source "fs/ext4/Kconfig" source "fs/jbd2/Kconfig" Loading
fs/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -49,6 +49,7 @@ obj-$(CONFIG_COREDUMP) += coredump.o obj-$(CONFIG_SYSCTL) += drop_caches.o obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FS_IOMAP) += iomap.o obj-y += quota/ Loading
fs/buffer.c +71 −5 Original line number Diff line number Diff line Loading @@ -21,6 +21,7 @@ #include <linux/kernel.h> #include <linux/syscalls.h> #include <linux/fs.h> #include <linux/iomap.h> #include <linux/mm.h> #include <linux/percpu.h> #include <linux/slab.h> Loading Loading @@ -1891,8 +1892,62 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) } EXPORT_SYMBOL(page_zero_new_buffers); int __block_write_begin(struct page *page, loff_t pos, unsigned len, get_block_t *get_block) static void iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh, struct iomap *iomap) { loff_t offset = block << inode->i_blkbits; bh->b_bdev = iomap->bdev; /* * Block points to offset in file we need to map, iomap contains * the offset at which the map starts. If the map ends before the * current block, then do not map the buffer and let the caller * handle it. */ BUG_ON(offset >= iomap->offset + iomap->length); switch (iomap->type) { case IOMAP_HOLE: /* * If the buffer is not up to date or beyond the current EOF, * we need to mark it as new to ensure sub-block zeroing is * executed if necessary. */ if (!buffer_uptodate(bh) || (offset >= i_size_read(inode))) set_buffer_new(bh); break; case IOMAP_DELALLOC: if (!buffer_uptodate(bh) || (offset >= i_size_read(inode))) set_buffer_new(bh); set_buffer_uptodate(bh); set_buffer_mapped(bh); set_buffer_delay(bh); break; case IOMAP_UNWRITTEN: /* * For unwritten regions, we always need to ensure that * sub-block writes cause the regions in the block we are not * writing to are zeroed. Set the buffer as new to ensure this. */ set_buffer_new(bh); set_buffer_unwritten(bh); /* FALLTHRU */ case IOMAP_MAPPED: if (offset >= i_size_read(inode)) set_buffer_new(bh); bh->b_blocknr = (iomap->blkno >> (inode->i_blkbits - 9)) + ((offset - iomap->offset) >> inode->i_blkbits); set_buffer_mapped(bh); break; } } int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap) { unsigned from = pos & (PAGE_SIZE - 1); unsigned to = from + len; Loading Loading @@ -1928,9 +1983,14 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len, clear_buffer_new(bh); if (!buffer_mapped(bh)) { WARN_ON(bh->b_size != blocksize); if (get_block) { err = get_block(inode, block, bh, 1); if (err) break; } else { iomap_to_bh(inode, block, bh, iomap); } if (buffer_new(bh)) { unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); Loading Loading @@ -1971,6 +2031,12 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len, page_zero_new_buffers(page, from, to); return err; } int __block_write_begin(struct page *page, loff_t pos, unsigned len, get_block_t *get_block) { return __block_write_begin_int(page, pos, len, get_block, NULL); } EXPORT_SYMBOL(__block_write_begin); static int __block_commit_write(struct inode *inode, struct page *page, Loading
fs/internal.h +3 −0 Original line number Diff line number Diff line Loading @@ -11,6 +11,7 @@ struct super_block; struct file_system_type; struct iomap; struct linux_binprm; struct path; struct mount; Loading Loading @@ -39,6 +40,8 @@ static inline int __sync_blockdev(struct block_device *bdev, int wait) * buffer.c */ extern void guard_bio_eod(int rw, struct bio *bio); extern int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, get_block_t *get_block, struct iomap *iomap); /* * char_dev.c Loading
fs/iomap.c 0 → 100644 +497 −0 Original line number Diff line number Diff line /* * Copyright (C) 2010 Red Hat, Inc. * Copyright (c) 2016 Christoph Hellwig. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ #include <linux/module.h> #include <linux/compiler.h> #include <linux/fs.h> #include <linux/iomap.h> #include <linux/uaccess.h> #include <linux/gfp.h> #include <linux/mm.h> #include <linux/swap.h> #include <linux/pagemap.h> #include <linux/file.h> #include <linux/uio.h> #include <linux/backing-dev.h> #include <linux/buffer_head.h> #include <linux/dax.h> #include "internal.h" typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, void *data, struct iomap *iomap); /* * Execute a iomap write on a segment of the mapping that spans a * contiguous range of pages that have identical block mapping state. * * This avoids the need to map pages individually, do individual allocations * for each page and most importantly avoid the need for filesystem specific * locking per page. Instead, all the operations are amortised over the entire * range of pages. It is assumed that the filesystems will lock whatever * resources they require in the iomap_begin call, and release them in the * iomap_end call. */ static loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, struct iomap_ops *ops, void *data, iomap_actor_t actor) { struct iomap iomap = { 0 }; loff_t written = 0, ret; /* * Need to map a range from start position for length bytes. This can * span multiple pages - it is only guaranteed to return a range of a * single type of pages (e.g. all into a hole, all mapped or all * unwritten). Failure at this point has nothing to undo. * * If allocation is required for this range, reserve the space now so * that the allocation is guaranteed to succeed later on. Once we copy * the data into the page cache pages, then we cannot fail otherwise we * expose transient stale data. If the reserve fails, we can safely * back out at this point as there is nothing to undo. */ ret = ops->iomap_begin(inode, pos, length, flags, &iomap); if (ret) return ret; if (WARN_ON(iomap.offset > pos)) return -EIO; /* * Cut down the length to the one actually provided by the filesystem, * as it might not be able to give us the whole size that we requested. */ if (iomap.offset + iomap.length < pos + length) length = iomap.offset + iomap.length - pos; /* * Now that we have guaranteed that the space allocation will succeed. * we can do the copy-in page by page without having to worry about * failures exposing transient data. */ written = actor(inode, pos, length, data, &iomap); /* * Now the data has been copied, commit the range we've copied. This * should not fail unless the filesystem has had a fatal error. */ ret = ops->iomap_end(inode, pos, length, written > 0 ? written : 0, flags, &iomap); return written ? written : ret; } static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { loff_t i_size = i_size_read(inode); /* * Only truncate newly allocated pages beyoned EOF, even if the * write started inside the existing inode size. */ if (pos + len > i_size) truncate_pagecache_range(inode, max(pos, i_size), pos + len); } static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, struct page **pagep, struct iomap *iomap) { pgoff_t index = pos >> PAGE_SHIFT; struct page *page; int status = 0; BUG_ON(pos + len > iomap->offset + iomap->length); page = grab_cache_page_write_begin(inode->i_mapping, index, flags); if (!page) return -ENOMEM; status = __block_write_begin_int(page, pos, len, NULL, iomap); if (unlikely(status)) { unlock_page(page); put_page(page); page = NULL; iomap_write_failed(inode, pos, len); } *pagep = page; return status; } static int iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, struct page *page) { int ret; ret = generic_write_end(NULL, inode->i_mapping, pos, len, copied, page, NULL); if (ret < len) iomap_write_failed(inode, pos, len); return ret; } static loff_t iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iov_iter *i = data; long status = 0; ssize_t written = 0; unsigned int flags = AOP_FLAG_NOFS; /* * Copies from kernel address space cannot fail (NFSD is a big user). */ if (!iter_is_iovec(i)) flags |= AOP_FLAG_UNINTERRUPTIBLE; do { struct page *page; unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ offset = (pos & (PAGE_SIZE - 1)); bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_count(i)); again: if (bytes > length) bytes = length; /* * Bring in the user page that we will copy from _first_. * Otherwise there's a nasty deadlock on copying from the * same page as we're writing to, without it being marked * up-to-date. * * Not only is this an optimisation, but it is also required * to check that the address is actually valid, when atomic * usercopies are used, below. */ if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; break; } status = iomap_write_begin(inode, pos, bytes, flags, &page, iomap); if (unlikely(status)) break; if (mapping_writably_mapped(inode->i_mapping)) flush_dcache_page(page); pagefault_disable(); copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); pagefault_enable(); flush_dcache_page(page); mark_page_accessed(page); status = iomap_write_end(inode, pos, bytes, copied, page); if (unlikely(status < 0)) break; copied = status; cond_resched(); iov_iter_advance(i, copied); if (unlikely(copied == 0)) { /* * If we were unable to copy any data at all, we must * fall back to a single segment length write. * * If we didn't fallback here, we could livelock * because not all segments in the iov can be copied at * once without a pagefault. */ bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_single_seg_count(i)); goto again; } pos += copied; written += copied; length -= copied; balance_dirty_pages_ratelimited(inode->i_mapping); } while (iov_iter_count(i) && length); return written ? written : status; } ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops) { struct inode *inode = iocb->ki_filp->f_mapping->host; loff_t pos = iocb->ki_pos, ret = 0, written = 0; while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), IOMAP_WRITE, ops, iter, iomap_write_actor); if (ret <= 0) break; pos += ret; written += ret; } return written ? written : ret; } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { struct page *page; int status; status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_UNINTERRUPTIBLE | AOP_FLAG_NOFS, &page, iomap); if (status) return status; zero_user(page, offset, bytes); mark_page_accessed(page); return iomap_write_end(inode, pos, bytes, bytes, page); } static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { sector_t sector = iomap->blkno + (((pos & ~(PAGE_SIZE - 1)) - iomap->offset) >> 9); return __dax_zero_page_range(iomap->bdev, sector, offset, bytes); } static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, void *data, struct iomap *iomap) { bool *did_zero = data; loff_t written = 0; int status; /* already zeroed? we're done. */ if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) return count; do { unsigned offset, bytes; offset = pos & (PAGE_SIZE - 1); /* Within page */ bytes = min_t(unsigned, PAGE_SIZE - offset, count); if (IS_DAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else status = iomap_zero(inode, pos, offset, bytes, iomap); if (status < 0) return status; pos += bytes; count -= bytes; written += bytes; if (did_zero) *did_zero = true; } while (count > 0); return written; } int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, struct iomap_ops *ops) { loff_t ret; while (len > 0) { ret = iomap_apply(inode, pos, len, IOMAP_ZERO, ops, did_zero, iomap_zero_range_actor); if (ret <= 0) return ret; pos += ret; len -= ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_zero_range); int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, struct iomap_ops *ops) { unsigned blocksize = (1 << inode->i_blkbits); unsigned off = pos & (blocksize - 1); /* Block boundary? Nothing to do */ if (!off) return 0; return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); } EXPORT_SYMBOL_GPL(iomap_truncate_page); static loff_t iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct page *page = data; int ret; ret = __block_write_begin_int(page, pos & ~PAGE_MASK, length, NULL, iomap); if (ret) return ret; block_commit_write(page, 0, length); return length; } int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap_ops *ops) { struct page *page = vmf->page; struct inode *inode = file_inode(vma->vm_file); unsigned long length; loff_t offset, size; ssize_t ret; lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || (page_offset(page) > size)) { /* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; } /* page is wholly or partially inside EOF */ if (((page->index + 1) << PAGE_SHIFT) > size) length = size & ~PAGE_MASK; else length = PAGE_SIZE; offset = page_offset(page); while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_WRITE, ops, page, iomap_page_mkwrite_actor); if (unlikely(ret <= 0)) goto out_unlock; offset += ret; length -= ret; } set_page_dirty(page); wait_for_stable_page(page); return 0; out_unlock: unlock_page(page); return ret; } EXPORT_SYMBOL_GPL(iomap_page_mkwrite); struct fiemap_ctx { struct fiemap_extent_info *fi; struct iomap prev; }; static int iomap_to_fiemap(struct fiemap_extent_info *fi, struct iomap *iomap, u32 flags) { switch (iomap->type) { case IOMAP_HOLE: /* skip holes */ return 0; case IOMAP_DELALLOC: flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN; break; case IOMAP_UNWRITTEN: flags |= FIEMAP_EXTENT_UNWRITTEN; break; case IOMAP_MAPPED: break; } return fiemap_fill_next_extent(fi, iomap->offset, iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0, iomap->length, flags | FIEMAP_EXTENT_MERGED); } static loff_t iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct fiemap_ctx *ctx = data; loff_t ret = length; if (iomap->type == IOMAP_HOLE) return length; ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0); ctx->prev = *iomap; switch (ret) { case 0: /* success */ return length; case 1: /* extent array full */ return 0; default: return ret; } } int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, loff_t start, loff_t len, struct iomap_ops *ops) { struct fiemap_ctx ctx; loff_t ret; memset(&ctx, 0, sizeof(ctx)); ctx.fi = fi; ctx.prev.type = IOMAP_HOLE; ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC); if (ret) return ret; ret = filemap_write_and_wait(inode->i_mapping); if (ret) return ret; while (len > 0) { ret = iomap_apply(inode, start, len, 0, ops, &ctx, iomap_fiemap_actor); if (ret < 0) return ret; if (ret == 0) break; start += ret; len -= ret; } if (ctx.prev.type != IOMAP_HOLE) { ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST); if (ret < 0) return ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_fiemap);
