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author | Nick Piggin <npiggin@suse.de> | 2007-10-16 01:25:01 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 09:42:55 -0700 |
commit | afddba49d18f346e5cc2938b6ed7c512db18ca68 (patch) | |
tree | 4726e3d3b0e9e8e5b5d3b2b0cccb36446bbdf3ca /drivers/block/loop.c | |
parent | 637aff46f94a754207c80c8c64bf1b74f24b967d (diff) | |
download | kernel_samsung_espresso10-afddba49d18f346e5cc2938b6ed7c512db18ca68.zip kernel_samsung_espresso10-afddba49d18f346e5cc2938b6ed7c512db18ca68.tar.gz kernel_samsung_espresso10-afddba49d18f346e5cc2938b6ed7c512db18ca68.tar.bz2 |
fs: introduce write_begin, write_end, and perform_write aops
These are intended to replace prepare_write and commit_write with more
flexible alternatives that are also able to avoid the buffered write
deadlock problems efficiently (which prepare_write is unable to do).
[mark.fasheh@oracle.com: API design contributions, code review and fixes]
[akpm@linux-foundation.org: various fixes]
[dmonakhov@sw.ru: new aop block_write_begin fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/loop.c')
-rw-r--r-- | drivers/block/loop.c | 75 |
1 files changed, 29 insertions, 46 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index b9233a0..a5f993a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -204,14 +204,13 @@ lo_do_transfer(struct loop_device *lo, int cmd, * do_lo_send_aops - helper for writing data to a loop device * * This is the fast version for backing filesystems which implement the address - * space operations prepare_write and commit_write. + * space operations write_begin and write_end. */ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, - int bsize, loff_t pos, struct page *page) + int bsize, loff_t pos, struct page *unused) { struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */ struct address_space *mapping = file->f_mapping; - const struct address_space_operations *aops = mapping->a_ops; pgoff_t index; unsigned offset, bv_offs; int len, ret; @@ -223,63 +222,47 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, len = bvec->bv_len; while (len > 0) { sector_t IV; - unsigned size; + unsigned size, copied; int transfer_result; + struct page *page; + void *fsdata; IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9); size = PAGE_CACHE_SIZE - offset; if (size > len) size = len; - page = grab_cache_page(mapping, index); - if (unlikely(!page)) + + ret = pagecache_write_begin(file, mapping, pos, size, 0, + &page, &fsdata); + if (ret) goto fail; - ret = aops->prepare_write(file, page, offset, - offset + size); - if (unlikely(ret)) { - if (ret == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - continue; - } - goto unlock; - } + transfer_result = lo_do_transfer(lo, WRITE, page, offset, bvec->bv_page, bv_offs, size, IV); - if (unlikely(transfer_result)) { - /* - * The transfer failed, but we still write the data to - * keep prepare/commit calls balanced. - */ - printk(KERN_ERR "loop: transfer error block %llu\n", - (unsigned long long)index); - zero_user_page(page, offset, size, KM_USER0); - } - flush_dcache_page(page); - ret = aops->commit_write(file, page, offset, - offset + size); - if (unlikely(ret)) { - if (ret == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - continue; - } - goto unlock; - } + copied = size; if (unlikely(transfer_result)) - goto unlock; - bv_offs += size; - len -= size; + copied = 0; + + ret = pagecache_write_end(file, mapping, pos, size, copied, + page, fsdata); + if (ret < 0) + goto fail; + if (ret < copied) + copied = ret; + + if (unlikely(transfer_result)) + goto fail; + + bv_offs += copied; + len -= copied; offset = 0; index++; - pos += size; - unlock_page(page); - page_cache_release(page); + pos += copied; } ret = 0; out: mutex_unlock(&mapping->host->i_mutex); return ret; -unlock: - unlock_page(page); - page_cache_release(page); fail: ret = -1; goto out; @@ -313,7 +296,7 @@ static int __do_lo_send_write(struct file *file, * do_lo_send_direct_write - helper for writing data to a loop device * * This is the fast, non-transforming version for backing filesystems which do - * not implement the address space operations prepare_write and commit_write. + * not implement the address space operations write_begin and write_end. * It uses the write file operation which should be present on all writeable * filesystems. */ @@ -332,7 +315,7 @@ static int do_lo_send_direct_write(struct loop_device *lo, * do_lo_send_write - helper for writing data to a loop device * * This is the slow, transforming version for filesystems which do not - * implement the address space operations prepare_write and commit_write. It + * implement the address space operations write_begin and write_end. It * uses the write file operation which should be present on all writeable * filesystems. * @@ -780,7 +763,7 @@ static int loop_set_fd(struct loop_device *lo, struct file *lo_file, */ if (!file->f_op->splice_read) goto out_putf; - if (aops->prepare_write && aops->commit_write) + if (aops->prepare_write || aops->write_begin) lo_flags |= LO_FLAGS_USE_AOPS; if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write) lo_flags |= LO_FLAGS_READ_ONLY; |