diff options
Diffstat (limited to 'fs/iomap.c')
| -rw-r--r-- | fs/iomap.c | 408 |
1 files changed, 384 insertions, 24 deletions
@@ -20,6 +20,7 @@ #include <linux/mm.h> #include <linux/swap.h> #include <linux/pagemap.h> +#include <linux/pagevec.h> #include <linux/file.h> #include <linux/uio.h> #include <linux/backing-dev.h> @@ -27,6 +28,7 @@ #include <linux/task_io_accounting_ops.h> #include <linux/dax.h> #include <linux/sched/signal.h> +#include <linux/swap.h> #include "internal.h" @@ -95,6 +97,12 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, return written ? written : ret; } +static sector_t +iomap_sector(struct iomap *iomap, loff_t pos) +{ + return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; +} + static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { @@ -352,11 +360,8 @@ static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { - sector_t sector = (iomap->addr + - (pos & PAGE_MASK) - iomap->offset) >> 9; - - return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, sector, - offset, bytes); + return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, + iomap_sector(iomap, pos & PAGE_MASK), offset, bytes); } static loff_t @@ -501,10 +506,13 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, case IOMAP_DELALLOC: flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN; break; + case IOMAP_MAPPED: + break; case IOMAP_UNWRITTEN: flags |= FIEMAP_EXTENT_UNWRITTEN; break; - case IOMAP_MAPPED: + case IOMAP_INLINE: + flags |= FIEMAP_EXTENT_DATA_INLINE; break; } @@ -512,8 +520,6 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, flags |= FIEMAP_EXTENT_MERGED; if (iomap->flags & IOMAP_F_SHARED) flags |= FIEMAP_EXTENT_SHARED; - if (iomap->flags & IOMAP_F_DATA_INLINE) - flags |= FIEMAP_EXTENT_DATA_INLINE; return fiemap_fill_next_extent(fi, iomap->offset, iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0, @@ -587,6 +593,113 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, } EXPORT_SYMBOL_GPL(iomap_fiemap); +/* + * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff. + * Returns true if found and updates @lastoff to the offset in file. + */ +static bool +page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff, + int whence) +{ + const struct address_space_operations *ops = inode->i_mapping->a_ops; + unsigned int bsize = i_blocksize(inode), off; + bool seek_data = whence == SEEK_DATA; + loff_t poff = page_offset(page); + + if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE)) + return false; + + if (*lastoff < poff) { + /* + * Last offset smaller than the start of the page means we found + * a hole: + */ + if (whence == SEEK_HOLE) + return true; + *lastoff = poff; + } + + /* + * Just check the page unless we can and should check block ranges: + */ + if (bsize == PAGE_SIZE || !ops->is_partially_uptodate) + return PageUptodate(page) == seek_data; + + lock_page(page); + if (unlikely(page->mapping != inode->i_mapping)) + goto out_unlock_not_found; + + for (off = 0; off < PAGE_SIZE; off += bsize) { + if ((*lastoff & ~PAGE_MASK) >= off + bsize) + continue; + if (ops->is_partially_uptodate(page, off, bsize) == seek_data) { + unlock_page(page); + return true; + } + *lastoff = poff + off + bsize; + } + +out_unlock_not_found: + unlock_page(page); + return false; +} + +/* + * Seek for SEEK_DATA / SEEK_HOLE in the page cache. + * + * Within unwritten extents, the page cache determines which parts are holes + * and which are data: uptodate buffer heads count as data; everything else + * counts as a hole. + * + * Returns the resulting offset on successs, and -ENOENT otherwise. + */ +static loff_t +page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, + int whence) +{ + pgoff_t index = offset >> PAGE_SHIFT; + pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE); + loff_t lastoff = offset; + struct pagevec pvec; + + if (length <= 0) + return -ENOENT; + + pagevec_init(&pvec); + + do { + unsigned nr_pages, i; + + nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index, + end - 1); + if (nr_pages == 0) + break; + + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + + if (page_seek_hole_data(inode, page, &lastoff, whence)) + goto check_range; + lastoff = page_offset(page) + PAGE_SIZE; + } + pagevec_release(&pvec); + } while (index < end); + + /* When no page at lastoff and we are not done, we found a hole. */ + if (whence != SEEK_HOLE) + goto not_found; + +check_range: + if (lastoff < offset + length) + goto out; +not_found: + lastoff = -ENOENT; +out: + pagevec_release(&pvec); + return lastoff; +} + + static loff_t iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, void *data, struct iomap *iomap) @@ -685,6 +798,8 @@ EXPORT_SYMBOL_GPL(iomap_seek_data); * Private flags for iomap_dio, must not overlap with the public ones in * iomap.h: */ +#define IOMAP_DIO_WRITE_FUA (1 << 28) +#define IOMAP_DIO_NEED_SYNC (1 << 29) #define IOMAP_DIO_WRITE (1 << 30) #define IOMAP_DIO_DIRTY (1 << 31) @@ -759,6 +874,13 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) dio_warn_stale_pagecache(iocb->ki_filp); } + /* + * If this is a DSYNC write, make sure we push it to stable storage now + * that we've written data. + */ + if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) + ret = generic_write_sync(iocb, ret); + inode_dio_end(file_inode(iocb->ki_filp)); kfree(dio); @@ -769,13 +891,8 @@ static void iomap_dio_complete_work(struct work_struct *work) { struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); struct kiocb *iocb = dio->iocb; - bool is_write = (dio->flags & IOMAP_DIO_WRITE); - ssize_t ret; - ret = iomap_dio_complete(dio); - if (is_write && ret > 0) - ret = generic_write_sync(iocb, ret); - iocb->ki_complete(iocb, ret, 0); + iocb->ki_complete(iocb, iomap_dio_complete(dio), 0); } /* @@ -833,14 +950,12 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, bio = bio_alloc(GFP_KERNEL, 1); bio_set_dev(bio, iomap->bdev); - bio->bi_iter.bi_sector = - (iomap->addr + pos - iomap->offset) >> 9; + bio->bi_iter.bi_sector = iomap_sector(iomap, pos); bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; get_page(page); - if (bio_add_page(bio, page, len, 0) != len) - BUG(); + __bio_add_page(bio, page, len, 0); bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC | REQ_IDLE); atomic_inc(&dio->ref); @@ -858,6 +973,7 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, struct iov_iter iter; struct bio *bio; bool need_zeroout = false; + bool use_fua = false; int nr_pages, ret; size_t copied = 0; @@ -881,8 +997,20 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, case IOMAP_MAPPED: if (iomap->flags & IOMAP_F_SHARED) dio->flags |= IOMAP_DIO_COW; - if (iomap->flags & IOMAP_F_NEW) + if (iomap->flags & IOMAP_F_NEW) { need_zeroout = true; + } else { + /* + * Use a FUA write if we need datasync semantics, this + * is a pure data IO that doesn't require any metadata + * updates and the underlying device supports FUA. This + * allows us to avoid cache flushes on IO completion. + */ + if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && + (dio->flags & IOMAP_DIO_WRITE_FUA) && + blk_queue_fua(bdev_get_queue(iomap->bdev))) + use_fua = true; + } break; default: WARN_ON_ONCE(1); @@ -916,8 +1044,7 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, bio = bio_alloc(GFP_KERNEL, nr_pages); bio_set_dev(bio, iomap->bdev); - bio->bi_iter.bi_sector = - (iomap->addr + pos - iomap->offset) >> 9; + bio->bi_iter.bi_sector = iomap_sector(iomap, pos); bio->bi_write_hint = dio->iocb->ki_hint; bio->bi_ioprio = dio->iocb->ki_ioprio; bio->bi_private = dio; @@ -931,10 +1058,14 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, n = bio->bi_iter.bi_size; if (dio->flags & IOMAP_DIO_WRITE) { - bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC | REQ_IDLE); + bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; + if (use_fua) + bio->bi_opf |= REQ_FUA; + else + dio->flags &= ~IOMAP_DIO_WRITE_FUA; task_io_account_write(n); } else { - bio_set_op_attrs(bio, REQ_OP_READ, 0); + bio->bi_opf = REQ_OP_READ; if (dio->flags & IOMAP_DIO_DIRTY) bio_set_pages_dirty(bio); } @@ -962,6 +1093,15 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, return copied; } +/* + * iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO + * is being issued as AIO or not. This allows us to optimise pure data writes + * to use REQ_FUA rather than requiring generic_write_sync() to issue a + * REQ_FLUSH post write. This is slightly tricky because a single request here + * can be mapped into multiple disjoint IOs and only a subset of the IOs issued + * may be pure data writes. In that case, we still need to do a full data sync + * completion. + */ ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, iomap_dio_end_io_t end_io) @@ -1006,8 +1146,21 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (iter->type == ITER_IOVEC) dio->flags |= IOMAP_DIO_DIRTY; } else { - dio->flags |= IOMAP_DIO_WRITE; flags |= IOMAP_WRITE; + dio->flags |= IOMAP_DIO_WRITE; + + /* for data sync or sync, we need sync completion processing */ + if (iocb->ki_flags & IOCB_DSYNC) + dio->flags |= IOMAP_DIO_NEED_SYNC; + + /* + * For datasync only writes, we optimistically try using FUA for + * this IO. Any non-FUA write that occurs will clear this flag, + * hence we know before completion whether a cache flush is + * necessary. + */ + if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) + dio->flags |= IOMAP_DIO_WRITE_FUA; } if (iocb->ki_flags & IOCB_NOWAIT) { @@ -1063,6 +1216,13 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (ret < 0) iomap_dio_set_error(dio, ret); + /* + * If all the writes we issued were FUA, we don't need to flush the + * cache on IO completion. Clear the sync flag for this case. + */ + if (dio->flags & IOMAP_DIO_WRITE_FUA) + dio->flags &= ~IOMAP_DIO_NEED_SYNC; + if (!atomic_dec_and_test(&dio->ref)) { if (!is_sync_kiocb(iocb)) return -EIOCBQUEUED; @@ -1090,3 +1250,203 @@ out_free_dio: return ret; } EXPORT_SYMBOL_GPL(iomap_dio_rw); + +/* Swapfile activation */ + +#ifdef CONFIG_SWAP +struct iomap_swapfile_info { + struct iomap iomap; /* accumulated iomap */ + struct swap_info_struct *sis; + uint64_t lowest_ppage; /* lowest physical addr seen (pages) */ + uint64_t highest_ppage; /* highest physical addr seen (pages) */ + unsigned long nr_pages; /* number of pages collected */ + int nr_extents; /* extent count */ +}; + +/* + * Collect physical extents for this swap file. Physical extents reported to + * the swap code must be trimmed to align to a page boundary. The logical + * offset within the file is irrelevant since the swapfile code maps logical + * page numbers of the swap device to the physical page-aligned extents. + */ +static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) +{ + struct iomap *iomap = &isi->iomap; + unsigned long nr_pages; + uint64_t first_ppage; + uint64_t first_ppage_reported; + uint64_t next_ppage; + int error; + + /* + * Round the start up and the end down so that the physical + * extent aligns to a page boundary. + */ + first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; + next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> + PAGE_SHIFT; + + /* Skip too-short physical extents. */ + if (first_ppage >= next_ppage) + return 0; + nr_pages = next_ppage - first_ppage; + + /* + * Calculate how much swap space we're adding; the first page contains + * the swap header and doesn't count. The mm still wants that first + * page fed to add_swap_extent, however. + */ + first_ppage_reported = first_ppage; + if (iomap->offset == 0) + first_ppage_reported++; + if (isi->lowest_ppage > first_ppage_reported) + isi->lowest_ppage = first_ppage_reported; + if (isi->highest_ppage < (next_ppage - 1)) + isi->highest_ppage = next_ppage - 1; + + /* Add extent, set up for the next call. */ + error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); + if (error < 0) + return error; + isi->nr_extents += error; + isi->nr_pages += nr_pages; + return 0; +} + +/* + * Accumulate iomaps for this swap file. We have to accumulate iomaps because + * swap only cares about contiguous page-aligned physical extents and makes no + * distinction between written and unwritten extents. + */ +static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, + loff_t count, void *data, struct iomap *iomap) +{ + struct iomap_swapfile_info *isi = data; + int error; + + switch (iomap->type) { + case IOMAP_MAPPED: + case IOMAP_UNWRITTEN: + /* Only real or unwritten extents. */ + break; + case IOMAP_INLINE: + /* No inline data. */ + pr_err("swapon: file is inline\n"); + return -EINVAL; + default: + pr_err("swapon: file has unallocated extents\n"); + return -EINVAL; + } + + /* No uncommitted metadata or shared blocks. */ + if (iomap->flags & IOMAP_F_DIRTY) { + pr_err("swapon: file is not committed\n"); + return -EINVAL; + } + if (iomap->flags & IOMAP_F_SHARED) { + pr_err("swapon: file has shared extents\n"); + return -EINVAL; + } + + /* Only one bdev per swap file. */ + if (iomap->bdev != isi->sis->bdev) { + pr_err("swapon: file is on multiple devices\n"); + return -EINVAL; + } + + if (isi->iomap.length == 0) { + /* No accumulated extent, so just store it. */ + memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); + } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { + /* Append this to the accumulated extent. */ + isi->iomap.length += iomap->length; + } else { + /* Otherwise, add the retained iomap and store this one. */ + error = iomap_swapfile_add_extent(isi); + if (error) + return error; + memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); + } + return count; +} + +/* + * Iterate a swap file's iomaps to construct physical extents that can be + * passed to the swapfile subsystem. + */ +int iomap_swapfile_activate(struct swap_info_struct *sis, + struct file *swap_file, sector_t *pagespan, + const struct iomap_ops *ops) +{ + struct iomap_swapfile_info isi = { + .sis = sis, + .lowest_ppage = (sector_t)-1ULL, + }; + struct address_space *mapping = swap_file->f_mapping; + struct inode *inode = mapping->host; + loff_t pos = 0; + loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE); + loff_t ret; + + ret = filemap_write_and_wait(inode->i_mapping); + if (ret) + return ret; + + while (len > 0) { + ret = iomap_apply(inode, pos, len, IOMAP_REPORT, + ops, &isi, iomap_swapfile_activate_actor); + if (ret <= 0) + return ret; + + pos += ret; + len -= ret; + } + + if (isi.iomap.length) { + ret = iomap_swapfile_add_extent(&isi); + if (ret) + return ret; + } + + *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; + sis->max = isi.nr_pages; + sis->pages = isi.nr_pages - 1; + sis->highest_bit = isi.nr_pages - 1; + return isi.nr_extents; +} +EXPORT_SYMBOL_GPL(iomap_swapfile_activate); +#endif /* CONFIG_SWAP */ + +static loff_t +iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, + void *data, struct iomap *iomap) +{ + sector_t *bno = data, addr; + + if (iomap->type == IOMAP_MAPPED) { + addr = (pos - iomap->offset + iomap->addr) >> inode->i_blkbits; + if (addr > INT_MAX) + WARN(1, "would truncate bmap result\n"); + else + *bno = addr; + } + return 0; +} + +/* legacy ->bmap interface. 0 is the error return (!) */ +sector_t +iomap_bmap(struct address_space *mapping, sector_t bno, + const struct iomap_ops *ops) +{ + struct inode *inode = mapping->host; + loff_t pos = bno >> inode->i_blkbits; + unsigned blocksize = i_blocksize(inode); + + if (filemap_write_and_wait(mapping)) + return 0; + + bno = 0; + iomap_apply(inode, pos, blocksize, 0, ops, &bno, iomap_bmap_actor); + return bno; +} +EXPORT_SYMBOL_GPL(iomap_bmap); |
