From 37be2f59d3149b95afaeeeff94edde2c07f165d2 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Thu, 8 Nov 2012 11:22:46 -0500 Subject: ext4: remove ext4_handle_release_buffer() ext4_handle_release_buffer() was intended to remove journal write access from a buffer, but it doesn't actually do anything at all other than add a BUFFER_TRACE point, but it's not reliably used for that either. Remove all the associated dead code. Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" Reviewed-by: Carlos Maiolino --- include/linux/jbd2.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux/jbd2.h') diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 3efc43f3f162..de7f55682088 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1096,7 +1096,6 @@ extern int jbd2_journal_get_undo_access(handle_t *, struct buffer_head *); void jbd2_journal_set_triggers(struct buffer_head *, struct jbd2_buffer_trigger_type *type); extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *); -extern void jbd2_journal_release_buffer (handle_t *, struct buffer_head *); extern int jbd2_journal_forget (handle_t *, struct buffer_head *); extern void journal_sync_buffer (struct buffer_head *); extern void jbd2_journal_invalidatepage(journal_t *, -- cgit v1.2.3 From fd47d3e1c2949838e858379aaf2bc20647be2912 Mon Sep 17 00:00:00 2001 From: Behan Webster Date: Thu, 8 Nov 2012 11:24:46 -0500 Subject: jbd2: remove VLAIS usage from JBD2 code The use of variable length arrays in structs (VLAIS) in the Linux Kernel code precludes the use of compilers which don't implement VLAIS (for instance the Clang compiler). Since ctx is always a 32-bit CRC, hard coding a size of 4 bytes accomplishes the same thing without the use of VLAIS. This is the same technique already employed in fs/ext4/ext4.h Signed-off-by: Mark Charlebois Signed-off-by: Behan Webster Signed-off-by: "Theodore Ts'o" --- include/linux/jbd2.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'include/linux/jbd2.h') diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index de7f55682088..1be23d9fdacb 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1302,15 +1302,21 @@ static inline int jbd_space_needed(journal_t *journal) extern int jbd_blocks_per_page(struct inode *inode); +/* JBD uses a CRC32 checksum */ +#define JBD_MAX_CHECKSUM_SIZE 4 + static inline u32 jbd2_chksum(journal_t *journal, u32 crc, const void *address, unsigned int length) { struct { struct shash_desc shash; - char ctx[crypto_shash_descsize(journal->j_chksum_driver)]; + char ctx[JBD_MAX_CHECKSUM_SIZE]; } desc; int err; + BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) > + JBD_MAX_CHECKSUM_SIZE); + desc.shash.tfm = journal->j_chksum_driver; desc.shash.flags = 0; *(u32 *)desc.ctx = crc; -- cgit v1.2.3 From 53e872681fed6a43047e71bf927f77d06f467988 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 25 Dec 2012 13:29:52 -0500 Subject: ext4: fix deadlock in journal_unmap_buffer() We cannot wait for transaction commit in journal_unmap_buffer() because we hold page lock which ranks below transaction start. We solve the issue by bailing out of journal_unmap_buffer() and jbd2_journal_invalidatepage() with -EBUSY. Caller is then responsible for waiting for transaction commit to finish and try invalidation again. Since the issue can happen only for page stradding i_size, it is simple enough to manually call jbd2_journal_invalidatepage() for such page from ext4_setattr(), check the return value and wait if necessary. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 82 ++++++++++++++++++++++++++++++++++++++++++++------- fs/jbd2/transaction.c | 27 +++++++++-------- include/linux/jbd2.h | 2 +- 3 files changed, 86 insertions(+), 25 deletions(-) (limited to 'include/linux/jbd2.h') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 12d3fbcff59f..cbfe13bf5b2a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2894,8 +2894,8 @@ static void ext4_invalidatepage(struct page *page, unsigned long offset) block_invalidatepage(page, offset); } -static void ext4_journalled_invalidatepage(struct page *page, - unsigned long offset) +static int __ext4_journalled_invalidatepage(struct page *page, + unsigned long offset) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); @@ -2907,7 +2907,14 @@ static void ext4_journalled_invalidatepage(struct page *page, if (offset == 0) ClearPageChecked(page); - jbd2_journal_invalidatepage(journal, page, offset); + return jbd2_journal_invalidatepage(journal, page, offset); +} + +/* Wrapper for aops... */ +static void ext4_journalled_invalidatepage(struct page *page, + unsigned long offset) +{ + WARN_ON(__ext4_journalled_invalidatepage(page, offset) < 0); } static int ext4_releasepage(struct page *page, gfp_t wait) @@ -4313,6 +4320,47 @@ int ext4_write_inode(struct inode *inode, struct writeback_control *wbc) return err; } +/* + * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate + * buffers that are attached to a page stradding i_size and are undergoing + * commit. In that case we have to wait for commit to finish and try again. + */ +static void ext4_wait_for_tail_page_commit(struct inode *inode) +{ + struct page *page; + unsigned offset; + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; + tid_t commit_tid = 0; + int ret; + + offset = inode->i_size & (PAGE_CACHE_SIZE - 1); + /* + * All buffers in the last page remain valid? Then there's nothing to + * do. We do the check mainly to optimize the common PAGE_CACHE_SIZE == + * blocksize case + */ + if (offset > PAGE_CACHE_SIZE - (1 << inode->i_blkbits)) + return; + while (1) { + page = find_lock_page(inode->i_mapping, + inode->i_size >> PAGE_CACHE_SHIFT); + if (!page) + return; + ret = __ext4_journalled_invalidatepage(page, offset); + unlock_page(page); + page_cache_release(page); + if (ret != -EBUSY) + return; + commit_tid = 0; + read_lock(&journal->j_state_lock); + if (journal->j_committing_transaction) + commit_tid = journal->j_committing_transaction->t_tid; + read_unlock(&journal->j_state_lock); + if (commit_tid) + jbd2_log_wait_commit(journal, commit_tid); + } +} + /* * ext4_setattr() * @@ -4426,16 +4474,28 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) } if (attr->ia_valid & ATTR_SIZE) { - if (attr->ia_size != i_size_read(inode)) { - truncate_setsize(inode, attr->ia_size); - /* Inode size will be reduced, wait for dio in flight. - * Temporarily disable dioread_nolock to prevent - * livelock. */ + if (attr->ia_size != inode->i_size) { + loff_t oldsize = inode->i_size; + + i_size_write(inode, attr->ia_size); + /* + * Blocks are going to be removed from the inode. Wait + * for dio in flight. Temporarily disable + * dioread_nolock to prevent livelock. + */ if (orphan) { - ext4_inode_block_unlocked_dio(inode); - inode_dio_wait(inode); - ext4_inode_resume_unlocked_dio(inode); + if (!ext4_should_journal_data(inode)) { + ext4_inode_block_unlocked_dio(inode); + inode_dio_wait(inode); + ext4_inode_resume_unlocked_dio(inode); + } else + ext4_wait_for_tail_page_commit(inode); } + /* + * Truncate pagecache after we've waited for commit + * in data=journal mode to make pages freeable. + */ + truncate_pagecache(inode, oldsize, inode->i_size); } ext4_truncate(inode); } diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index cd4485db42b3..ddc51a7f4508 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1840,7 +1840,6 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, BUFFER_TRACE(bh, "entry"); -retry: /* * It is safe to proceed here without the j_list_lock because the * buffers cannot be stolen by try_to_free_buffers as long as we are @@ -1935,14 +1934,11 @@ retry: * for commit and try again. */ if (partial_page) { - tid_t tid = journal->j_committing_transaction->t_tid; - jbd2_journal_put_journal_head(jh); spin_unlock(&journal->j_list_lock); jbd_unlock_bh_state(bh); write_unlock(&journal->j_state_lock); - jbd2_log_wait_commit(journal, tid); - goto retry; + return -EBUSY; } /* * OK, buffer won't be reachable after truncate. We just set @@ -2003,21 +1999,23 @@ zap_buffer_unlocked: * @page: page to flush * @offset: length of page to invalidate. * - * Reap page buffers containing data after offset in page. - * + * Reap page buffers containing data after offset in page. Can return -EBUSY + * if buffers are part of the committing transaction and the page is straddling + * i_size. Caller then has to wait for current commit and try again. */ -void jbd2_journal_invalidatepage(journal_t *journal, - struct page *page, - unsigned long offset) +int jbd2_journal_invalidatepage(journal_t *journal, + struct page *page, + unsigned long offset) { struct buffer_head *head, *bh, *next; unsigned int curr_off = 0; int may_free = 1; + int ret = 0; if (!PageLocked(page)) BUG(); if (!page_has_buffers(page)) - return; + return 0; /* We will potentially be playing with lists other than just the * data lists (especially for journaled data mode), so be @@ -2031,9 +2029,11 @@ void jbd2_journal_invalidatepage(journal_t *journal, if (offset <= curr_off) { /* This block is wholly outside the truncation point */ lock_buffer(bh); - may_free &= journal_unmap_buffer(journal, bh, - offset > 0); + ret = journal_unmap_buffer(journal, bh, offset > 0); unlock_buffer(bh); + if (ret < 0) + return ret; + may_free &= ret; } curr_off = next_off; bh = next; @@ -2044,6 +2044,7 @@ void jbd2_journal_invalidatepage(journal_t *journal, if (may_free && try_to_free_buffers(page)) J_ASSERT(!page_has_buffers(page)); } + return 0; } /* diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 1be23d9fdacb..e30b66346942 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1098,7 +1098,7 @@ void jbd2_journal_set_triggers(struct buffer_head *, extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *); extern int jbd2_journal_forget (handle_t *, struct buffer_head *); extern void journal_sync_buffer (struct buffer_head *); -extern void jbd2_journal_invalidatepage(journal_t *, +extern int jbd2_journal_invalidatepage(journal_t *, struct page *, unsigned long); extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t); extern int jbd2_journal_stop(handle_t *); -- cgit v1.2.3