Hi Dmitry,
FYI, there are new smatch warnings show up in
tree: git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
head: 07043757c1a4018a04aded14deb1f28269a4b2ad
commit: c6a59106b4106d13dc824a388c5572ddd65a0779 [47/50] ext4: punch_hole should wait for DIO writers
arch/x86/include/asm/jump_label.h:25 arch_static_branch() info: ignoring unreachable code.
+ fs/ext4/extents.c:4949 ext4_ext_punch_hole() warn: inconsistent returns mutex:&inode->i_mutex: locked (4813,4815) unlocked (4806,4949)
vim +4949 fs/ext4/extents.c
c6a59106 (Dmitry Monakhov 2012-09-29 4800) */
c6a59106 (Dmitry Monakhov 2012-09-29 4801) if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
c6a59106 (Dmitry Monakhov 2012-09-29 4802) err = filemap_write_and_wait_range(mapping,
c6a59106 (Dmitry Monakhov 2012-09-29 4803) offset, offset + length - 1);
c6a59106 (Dmitry Monakhov 2012-09-29 4804)
c6a59106 (Dmitry Monakhov 2012-09-29 4805) if (err)
c6a59106 (Dmitry Monakhov 2012-09-29 4806) return err;
c6a59106 (Dmitry Monakhov 2012-09-29 4807) }
c6a59106 (Dmitry Monakhov 2012-09-29 4808)
c6a59106 (Dmitry Monakhov 2012-09-29 4809) mutex_lock(&inode->i_mutex);
c6a59106 (Dmitry Monakhov 2012-09-29 4810) /* Need recheck file flags under mutex */
c6a59106 (Dmitry Monakhov 2012-09-29 4811) /* It's not possible punch hole on append only file */
c6a59106 (Dmitry Monakhov 2012-09-29 4812) if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
c6a59106 (Dmitry Monakhov 2012-09-29 4813) return -EPERM;
c6a59106 (Dmitry Monakhov 2012-09-29 4814) if (IS_SWAPFILE(inode))
c6a59106 (Dmitry Monakhov 2012-09-29 4815) return -ETXTBSY;
c6a59106 (Dmitry Monakhov 2012-09-29 4816)
2be4751b (Allison Henderson 2011-09-03 4817) /* No need to punch hole beyond i_size */
2be4751b (Allison Henderson 2011-09-03 4818) if (offset >= inode->i_size)
c6a59106 (Dmitry Monakhov 2012-09-29 4819) goto out_mutex;
2be4751b (Allison Henderson 2011-09-03 4820)
2be4751b (Allison Henderson 2011-09-03 4821) /*
2be4751b (Allison Henderson 2011-09-03 4822) * If the hole extends beyond i_size, set the hole
2be4751b (Allison Henderson 2011-09-03 4823) * to end after the page that contains i_size
2be4751b (Allison Henderson 2011-09-03 4824) */
2be4751b (Allison Henderson 2011-09-03 4825) if (offset + length > inode->i_size) {
2be4751b (Allison Henderson 2011-09-03 4826) length = inode->i_size +
2be4751b (Allison Henderson 2011-09-03 4827) PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) -
2be4751b (Allison Henderson 2011-09-03 4828) offset;
2be4751b (Allison Henderson 2011-09-03 4829) }
2be4751b (Allison Henderson 2011-09-03 4830)
a4bb6b64 (Allison Henderson 2011-05-25 4831) first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
a4bb6b64 (Allison Henderson 2011-05-25 4832) last_page = (offset + length) >> PAGE_CACHE_SHIFT;
a4bb6b64 (Allison Henderson 2011-05-25 4833)
a4bb6b64 (Allison Henderson 2011-05-25 4834) first_page_offset = first_page << PAGE_CACHE_SHIFT;
a4bb6b64 (Allison Henderson 2011-05-25 4835) last_page_offset = last_page << PAGE_CACHE_SHIFT;
a4bb6b64 (Allison Henderson 2011-05-25 4836)
a4bb6b64 (Allison Henderson 2011-05-25 4837) /* Now release the pages */
a4bb6b64 (Allison Henderson 2011-05-25 4838) if (last_page_offset > first_page_offset) {
5e44f8c3 (Hugh Dickins 2012-06-01 4839) truncate_pagecache_range(inode, first_page_offset,
5e44f8c3 (Hugh Dickins 2012-06-01 4840) last_page_offset - 1);
a4bb6b64 (Allison Henderson 2011-05-25 4841) }
a4bb6b64 (Allison Henderson 2011-05-25 4842)
c6a59106 (Dmitry Monakhov 2012-09-29 4843) /* Wait all existing dio workers, newcomers will block on i_mutex */
c6a59106 (Dmitry Monakhov 2012-09-29 4844) ext4_inode_block_unlocked_dio(inode);
c6a59106 (Dmitry Monakhov 2012-09-29 4845) inode_dio_wait(inode);
d1579744 (Dmitry Monakhov 2012-09-29 4846) err = ext4_flush_completed_IO(inode);
d1579744 (Dmitry Monakhov 2012-09-29 4847) if (err)
c6a59106 (Dmitry Monakhov 2012-09-29 4848) goto out_dio;
a4bb6b64 (Allison Henderson 2011-05-25 4849)
a4bb6b64 (Allison Henderson 2011-05-25 4850) credits = ext4_writepage_trans_blocks(inode);
a4bb6b64 (Allison Henderson 2011-05-25 4851) handle = ext4_journal_start(inode, credits);
c6a59106 (Dmitry Monakhov 2012-09-29 4852) if (IS_ERR(handle)) {
c6a59106 (Dmitry Monakhov 2012-09-29 4853) err = PTR_ERR(handle);
c6a59106 (Dmitry Monakhov 2012-09-29 4854) goto out_dio;
c6a59106 (Dmitry Monakhov 2012-09-29 4855) }
a4bb6b64 (Allison Henderson 2011-05-25 4856)
a4bb6b64 (Allison Henderson 2011-05-25 4857)
a4bb6b64 (Allison Henderson 2011-05-25 4858) /*
ba06208a (Allison Henderson 2011-09-03 4859) * Now we need to zero out the non-page-aligned data in the
ba06208a (Allison Henderson 2011-09-03 4860) * pages at the start and tail of the hole, and unmap the buffer
ba06208a (Allison Henderson 2011-09-03 4861) * heads for the block aligned regions of the page that were
ba06208a (Allison Henderson 2011-09-03 4862) * completely zeroed.
a4bb6b64 (Allison Henderson 2011-05-25 4863) */
ba06208a (Allison Henderson 2011-09-03 4864) if (first_page > last_page) {
ba06208a (Allison Henderson 2011-09-03 4865) /*
ba06208a (Allison Henderson 2011-09-03 4866) * If the file space being truncated is contained within a page
ba06208a (Allison Henderson 2011-09-03 4867) * just zero out and unmap the middle of that page
ba06208a (Allison Henderson 2011-09-03 4868) */
ba06208a (Allison Henderson 2011-09-03 4869) err = ext4_discard_partial_page_buffers(handle,
ba06208a (Allison Henderson 2011-09-03 4870) mapping, offset, length, 0);
ba06208a (Allison Henderson 2011-09-03 4871)
ba06208a (Allison Henderson 2011-09-03 4872) if (err)
ba06208a (Allison Henderson 2011-09-03 4873) goto out;
ba06208a (Allison Henderson 2011-09-03 4874) } else {
ba06208a (Allison Henderson 2011-09-03 4875) /*
ba06208a (Allison Henderson 2011-09-03 4876) * zero out and unmap the partial page that contains
ba06208a (Allison Henderson 2011-09-03 4877) * the start of the hole
ba06208a (Allison Henderson 2011-09-03 4878) */
ba06208a (Allison Henderson 2011-09-03 4879) page_len = first_page_offset - offset;
ba06208a (Allison Henderson 2011-09-03 4880) if (page_len > 0) {
ba06208a (Allison Henderson 2011-09-03 4881) err = ext4_discard_partial_page_buffers(handle, mapping,
ba06208a (Allison Henderson 2011-09-03 4882) offset, page_len, 0);
ba06208a (Allison Henderson 2011-09-03 4883) if (err)
ba06208a (Allison Henderson 2011-09-03 4884) goto out;
ba06208a (Allison Henderson 2011-09-03 4885) }
ba06208a (Allison Henderson 2011-09-03 4886)
ba06208a (Allison Henderson 2011-09-03 4887) /*
ba06208a (Allison Henderson 2011-09-03 4888) * zero out and unmap the partial page that contains
ba06208a (Allison Henderson 2011-09-03 4889) * the end of the hole
ba06208a (Allison Henderson 2011-09-03 4890) */
ba06208a (Allison Henderson 2011-09-03 4891) page_len = offset + length - last_page_offset;
ba06208a (Allison Henderson 2011-09-03 4892) if (page_len > 0) {
ba06208a (Allison Henderson 2011-09-03 4893) err = ext4_discard_partial_page_buffers(handle, mapping,
ba06208a (Allison Henderson 2011-09-03 4894) last_page_offset, page_len, 0);
ba06208a (Allison Henderson 2011-09-03 4895) if (err)
ba06208a (Allison Henderson 2011-09-03 4896) goto out;
a4bb6b64 (Allison Henderson 2011-05-25 4897) }
a4bb6b64 (Allison Henderson 2011-05-25 4898) }
a4bb6b64 (Allison Henderson 2011-05-25 4899)
2be4751b (Allison Henderson 2011-09-03 4900) /*
2be4751b (Allison Henderson 2011-09-03 4901) * If i_size is contained in the last page, we need to
2be4751b (Allison Henderson 2011-09-03 4902) * unmap and zero the partial page after i_size
2be4751b (Allison Henderson 2011-09-03 4903) */
2be4751b (Allison Henderson 2011-09-03 4904) if (inode->i_size >> PAGE_CACHE_SHIFT == last_page &&
2be4751b (Allison Henderson 2011-09-03 4905) inode->i_size % PAGE_CACHE_SIZE != 0) {
2be4751b (Allison Henderson 2011-09-03 4906)
2be4751b (Allison Henderson 2011-09-03 4907) page_len = PAGE_CACHE_SIZE -
2be4751b (Allison Henderson 2011-09-03 4908) (inode->i_size & (PAGE_CACHE_SIZE - 1));
2be4751b (Allison Henderson 2011-09-03 4909)
2be4751b (Allison Henderson 2011-09-03 4910) if (page_len > 0) {
2be4751b (Allison Henderson 2011-09-03 4911) err = ext4_discard_partial_page_buffers(handle,
2be4751b (Allison Henderson 2011-09-03 4912) mapping, inode->i_size, page_len, 0);
2be4751b (Allison Henderson 2011-09-03 4913)
2be4751b (Allison Henderson 2011-09-03 4914) if (err)
2be4751b (Allison Henderson 2011-09-03 4915) goto out;
2be4751b (Allison Henderson 2011-09-03 4916) }
2be4751b (Allison Henderson 2011-09-03 4917) }
2be4751b (Allison Henderson 2011-09-03 4918)
5f95d21f (Lukas Czerner 2012-03-19 4919) first_block = (offset + sb->s_blocksize - 1) >>
5f95d21f (Lukas Czerner 2012-03-19 4920) EXT4_BLOCK_SIZE_BITS(sb);
5f95d21f (Lukas Czerner 2012-03-19 4921) stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
5f95d21f (Lukas Czerner 2012-03-19 4922)
a4bb6b64 (Allison Henderson 2011-05-25 4923) /* If there are no blocks to remove, return now */
5f95d21f (Lukas Czerner 2012-03-19 4924) if (first_block >= stop_block)
a4bb6b64 (Allison Henderson 2011-05-25 4925) goto out;
a4bb6b64 (Allison Henderson 2011-05-25 4926)
a4bb6b64 (Allison Henderson 2011-05-25 4927) down_write(&EXT4_I(inode)->i_data_sem);
a4bb6b64 (Allison Henderson 2011-05-25 4928) ext4_ext_invalidate_cache(inode);
a4bb6b64 (Allison Henderson 2011-05-25 4929) ext4_discard_preallocations(inode);
a4bb6b64 (Allison Henderson 2011-05-25 4930)
5f95d21f (Lukas Czerner 2012-03-19 4931) err = ext4_ext_remove_space(inode, first_block, stop_block - 1);
a4bb6b64 (Allison Henderson 2011-05-25 4932)
5f95d21f (Lukas Czerner 2012-03-19 4933) ext4_ext_invalidate_cache(inode);
5f95d21f (Lukas Czerner 2012-03-19 4934) ext4_discard_preallocations(inode);
a4bb6b64 (Allison Henderson 2011-05-25 4935)
a4bb6b64 (Allison Henderson 2011-05-25 4936) if (IS_SYNC(inode))
a4bb6b64 (Allison Henderson 2011-05-25 4937) ext4_handle_sync(handle);
a4bb6b64 (Allison Henderson 2011-05-25 4938)
a4bb6b64 (Allison Henderson 2011-05-25 4939) up_write(&EXT4_I(inode)->i_data_sem);
a4bb6b64 (Allison Henderson 2011-05-25 4940)
a4bb6b64 (Allison Henderson 2011-05-25 4941) out:
a4bb6b64 (Allison Henderson 2011-05-25 4942) inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
a4bb6b64 (Allison Henderson 2011-05-25 4943) ext4_mark_inode_dirty(handle, inode);
a4bb6b64 (Allison Henderson 2011-05-25 4944) ext4_journal_stop(handle);
c6a59106 (Dmitry Monakhov 2012-09-29 4945) out_dio:
c6a59106 (Dmitry Monakhov 2012-09-29 4946) ext4_inode_resume_unlocked_dio(inode);
c6a59106 (Dmitry Monakhov 2012-09-29 4947) out_mutex:
c6a59106 (Dmitry Monakhov 2012-09-29 4948) mutex_unlock(&inode->i_mutex);
a4bb6b64 (Allison Henderson 2011-05-25 @4949) return err;
a4bb6b64 (Allison Henderson 2011-05-25 4950) }
6873fa0d (Eric Sandeen 2008-10-07 4951) int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
6873fa0d (Eric Sandeen 2008-10-07 4952) __u64 start, __u64 len)
The code at line 4949 was first introduced by commit:
a4bb6b6 ext4: enable "punch hole" functionality
---
0-DAY kernel build testing backend Open Source Technology Centre
Fengguang Wu, Yuanhan Liu Intel Corporation
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