[PATCHv2 0/5] ext4/jbd2: inline_data fixes and minor cleanups

[PATCHv2 0/5] ext4/jbd2: inline_data fixes and minor cleanups

[Ritesh Harjani]

Hello,

Please find v2 of the inline_data fixes and some minor cleanups found during
code review.

I have dropped patch-6 in v2 which was removing use of t_handle_lock (spinlock)
from within jbd2_journal_wait_updates(). Based on Jan comments, I feel we can
push that as killing of t_handle_lock into a separate series (which will be on
top of this).

v1 -> v2
========
1. Added Jan's Reviewed-by tag & addressed one of his comment on no need to make
jbd2_journal_wait_updates() function inline.
2. Dropped patch-6 as described above.

Description
============
Patch[1]: fixes BUG_ON with inline_data which was reported [1] with generic/475.

Patch[2]: is mostly cleanup found during code review of inline_data code.

Patch[3]: is a possible memory corruption fix in case of krealloc failure.

Patch[4-5]: Cleanups.

[v1]: https://lore.kernel.org/linux-ext4/cover.1642044249.git.riteshh@linux.ibm.com/T/

Ritesh Harjani (5):
  ext4: Fix error handling in ext4_restore_inline_data()
  ext4: Remove redundant max inline_size check in ext4_da_write_inline_data_begin()
  ext4: Fix error handling in ext4_fc_record_modified_inode()
  jbd2: Cleanup unused functions declarations from jbd2.h
  jbd2: Refactor wait logic for transaction updates into a common function

 fs/ext4/fast_commit.c | 64 ++++++++++++++++++++-----------------------
 fs/ext4/inline.c      | 23 +++++++++-------
 fs/jbd2/commit.c      | 19 ++-----------
 fs/jbd2/transaction.c | 53 +++++++++++++++++++++--------------
 include/linux/jbd2.h  | 11 ++------
 5 files changed, 80 insertions(+), 90 deletions(-)

--
2.31.1

[PATCHv2 1/5] ext4: Fix error handling in ext4_restore_inline_data()

[Ritesh Harjani]

While running "./check -I 200 generic/475" it sometimes gives below
kernel BUG(). Ideally we should not call ext4_write_inline_data() if
ext4_create_inline_data() has failed.

<log snip>
[73131.453234] kernel BUG at fs/ext4/inline.c:223!

<code snip>
 212 static void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
 213                                    void *buffer, loff_t pos, unsigned int len)
 214 {
<...>
 223         BUG_ON(!EXT4_I(inode)->i_inline_off);
 224         BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);

This patch handles the error and prints out a emergency msg saying potential
data loss for the given inode (since we couldn't restore the original
inline_data due to some previous error).

[ 9571.070313] EXT4-fs (dm-0): error restoring inline_data for inode -- potential data loss! (inode 1703982, error -30)

Reported-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inline.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 39a1ab129fdc..d091133a4b46 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1133,7 +1133,15 @@ static void ext4_restore_inline_data(handle_t *handle, struct inode *inode,
 				     struct ext4_iloc *iloc,
 				     void *buf, int inline_size)
 {
-	ext4_create_inline_data(handle, inode, inline_size);
+	int ret;
+
+	ret = ext4_create_inline_data(handle, inode, inline_size);
+	if (ret) {
+		ext4_msg(inode->i_sb, KERN_EMERG,
+			"error restoring inline_data for inode -- potential data loss! (inode %lu, error %d)",
+			inode->i_ino, ret);
+		return;
+	}
 	ext4_write_inline_data(inode, iloc, buf, 0, inline_size);
 	ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
 }
-- 
2.31.1

[PATCHv2 2/5] ext4: Remove redundant max inline_size check in ext4_da_write_inline_data_begin()

[Ritesh Harjani]

ext4_prepare_inline_data() already checks for ext4_get_max_inline_size()
and returns -ENOSPC. So there is no need to check it twice within
ext4_da_write_inline_data_begin(). This patch removes the extra check.

It also makes it more clean.

No functionality change in this patch.

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inline.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index d091133a4b46..cbdd84e49f2c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -911,7 +911,7 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping,
 				    struct page **pagep,
 				    void **fsdata)
 {
-	int ret, inline_size;
+	int ret;
 	handle_t *handle;
 	struct page *page;
 	struct ext4_iloc iloc;
@@ -928,14 +928,9 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping,
 		goto out;
 	}
 
-	inline_size = ext4_get_max_inline_size(inode);
-
-	ret = -ENOSPC;
-	if (inline_size >= pos + len) {
-		ret = ext4_prepare_inline_data(handle, inode, pos + len);
-		if (ret && ret != -ENOSPC)
-			goto out_journal;
-	}
+	ret = ext4_prepare_inline_data(handle, inode, pos + len);
+	if (ret && ret != -ENOSPC)
+		goto out_journal;
 
 	/*
 	 * We cannot recurse into the filesystem as the transaction
-- 
2.31.1

[PATCHv2 3/5] ext4: Fix error handling in ext4_fc_record_modified_inode()

[Ritesh Harjani]

Current code does not fully takes care of krealloc() error case,
which could lead to silent memory corruption or a kernel bug.
This patch fixes that.

Also it cleans up some duplicated error handling logic from various functions
in fast_commit.c file.

Reported-by: luo penghao <luo.penghao@zte.com.cn>
Suggested-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/fast_commit.c | 64 ++++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 35 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 5ae8026a0c56..4541c8468c01 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1392,14 +1392,15 @@ static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
 		if (state->fc_modified_inodes[i] == ino)
 			return 0;
 	if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
-		state->fc_modified_inodes_size +=
-			EXT4_FC_REPLAY_REALLOC_INCREMENT;
 		state->fc_modified_inodes = krealloc(
-					state->fc_modified_inodes, sizeof(int) *
-					state->fc_modified_inodes_size,
-					GFP_KERNEL);
+				state->fc_modified_inodes,
+				sizeof(int) * (state->fc_modified_inodes_size +
+				EXT4_FC_REPLAY_REALLOC_INCREMENT),
+				GFP_KERNEL);
 		if (!state->fc_modified_inodes)
 			return -ENOMEM;
+		state->fc_modified_inodes_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
 	}
 	state->fc_modified_inodes[state->fc_modified_inodes_used++] = ino;
 	return 0;
@@ -1431,7 +1432,9 @@ static int ext4_fc_replay_inode(struct super_block *sb, struct ext4_fc_tl *tl,
 	}
 	inode = NULL;
 
-	ext4_fc_record_modified_inode(sb, ino);
+	ret = ext4_fc_record_modified_inode(sb, ino);
+	if (ret)
+		goto out;
 
 	raw_fc_inode = (struct ext4_inode *)
 		(val + offsetof(struct ext4_fc_inode, fc_raw_inode));
@@ -1621,6 +1624,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 	}
 
 	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
 
 	start = le32_to_cpu(ex->ee_block);
 	start_pblk = ext4_ext_pblock(ex);
@@ -1638,18 +1643,14 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 		map.m_pblk = 0;
 		ret = ext4_map_blocks(NULL, inode, &map, 0);
 
-		if (ret < 0) {
-			iput(inode);
-			return 0;
-		}
+		if (ret < 0)
+			goto out;
 
 		if (ret == 0) {
 			/* Range is not mapped */
 			path = ext4_find_extent(inode, cur, NULL, 0);
-			if (IS_ERR(path)) {
-				iput(inode);
-				return 0;
-			}
+			if (IS_ERR(path))
+				goto out;
 			memset(&newex, 0, sizeof(newex));
 			newex.ee_block = cpu_to_le32(cur);
 			ext4_ext_store_pblock(
@@ -1663,10 +1664,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 			up_write((&EXT4_I(inode)->i_data_sem));
 			ext4_ext_drop_refs(path);
 			kfree(path);
-			if (ret) {
-				iput(inode);
-				return 0;
-			}
+			if (ret)
+				goto out;
 			goto next;
 		}
 
@@ -1679,10 +1678,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 			ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
 					ext4_ext_is_unwritten(ex),
 					start_pblk + cur - start);
-			if (ret) {
-				iput(inode);
-				return 0;
-			}
+			if (ret)
+				goto out;
 			/*
 			 * Mark the old blocks as free since they aren't used
 			 * anymore. We maintain an array of all the modified
@@ -1702,10 +1699,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 			ext4_ext_is_unwritten(ex), map.m_pblk);
 		ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
 					ext4_ext_is_unwritten(ex), map.m_pblk);
-		if (ret) {
-			iput(inode);
-			return 0;
-		}
+		if (ret)
+			goto out;
 		/*
 		 * We may have split the extent tree while toggling the state.
 		 * Try to shrink the extent tree now.
@@ -1717,6 +1712,7 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
 	}
 	ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
 					sb->s_blocksize_bits);
+out:
 	iput(inode);
 	return 0;
 }
@@ -1746,6 +1742,8 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
 	}
 
 	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
 
 	jbd_debug(1, "DEL_RANGE, inode %ld, lblk %d, len %d\n",
 			inode->i_ino, le32_to_cpu(lrange.fc_lblk),
@@ -1755,10 +1753,8 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
 		map.m_len = remaining;
 
 		ret = ext4_map_blocks(NULL, inode, &map, 0);
-		if (ret < 0) {
-			iput(inode);
-			return 0;
-		}
+		if (ret < 0)
+			goto out;
 		if (ret > 0) {
 			remaining -= ret;
 			cur += ret;
@@ -1773,15 +1769,13 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
 	ret = ext4_ext_remove_space(inode, lrange.fc_lblk,
 				lrange.fc_lblk + lrange.fc_len - 1);
 	up_write(&EXT4_I(inode)->i_data_sem);
-	if (ret) {
-		iput(inode);
-		return 0;
-	}
+	if (ret)
+		goto out;
 	ext4_ext_replay_shrink_inode(inode,
 		i_size_read(inode) >> sb->s_blocksize_bits);
 	ext4_mark_inode_dirty(NULL, inode);
+out:
 	iput(inode);
-
 	return 0;
 }
 
-- 
2.31.1

[PATCHv2 4/5] jbd2: Cleanup unused functions declarations from jbd2.h

[Ritesh Harjani]

During code review found no references of few of these below function
declarations. This patch cleans those up from jbd2.h

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 include/linux/jbd2.h | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index fd933c45281a..f76598265896 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1419,9 +1419,7 @@ extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
 extern bool __jbd2_journal_refile_buffer(struct journal_head *);
 extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
 extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
-extern void __journal_free_buffer(struct journal_head *bh);
 extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
-extern void __journal_clean_data_list(transaction_t *transaction);
 static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh)
 {
 	list_add_tail(&bh->b_assoc_buffers, head);
@@ -1486,9 +1484,6 @@ extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 					      struct buffer_head **bh_out,
 					      sector_t blocknr);
 
-/* Transaction locking */
-extern void		__wait_on_journal (journal_t *);
-
 /* Transaction cache support */
 extern void jbd2_journal_destroy_transaction_cache(void);
 extern int __init jbd2_journal_init_transaction_cache(void);
@@ -1774,8 +1769,6 @@ static inline unsigned long jbd2_log_space_left(journal_t *journal)
 #define BJ_Reserved	4	/* Buffer is reserved for access by journal */
 #define BJ_Types	5
 
-extern int jbd_blocks_per_page(struct inode *inode);
-
 /* JBD uses a CRC32 checksum */
 #define JBD_MAX_CHECKSUM_SIZE 4
 
-- 
2.31.1

[PATCHv2 5/5] jbd2: Refactor wait logic for transaction updates into a common function

[Ritesh Harjani]

No functionality change as such in this patch. This only refactors the
common piece of code which waits for t_updates to finish into a common
function named as jbd2_journal_wait_updates(journal_t *)

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/jbd2/commit.c      | 19 +++-------------
 fs/jbd2/transaction.c | 53 ++++++++++++++++++++++++++-----------------
 include/linux/jbd2.h  |  4 +++-
 3 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 3cc4ab2ba7f4..428364f107be 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -484,22 +484,9 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
 					      stats.run.rs_locked);
 
-	spin_lock(&commit_transaction->t_handle_lock);
-	while (atomic_read(&commit_transaction->t_updates)) {
-		DEFINE_WAIT(wait);
+	// waits for any t_updates to finish
+	jbd2_journal_wait_updates(journal);
 
-		prepare_to_wait(&journal->j_wait_updates, &wait,
-					TASK_UNINTERRUPTIBLE);
-		if (atomic_read(&commit_transaction->t_updates)) {
-			spin_unlock(&commit_transaction->t_handle_lock);
-			write_unlock(&journal->j_state_lock);
-			schedule();
-			write_lock(&journal->j_state_lock);
-			spin_lock(&commit_transaction->t_handle_lock);
-		}
-		finish_wait(&journal->j_wait_updates, &wait);
-	}
-	spin_unlock(&commit_transaction->t_handle_lock);
 	commit_transaction->t_state = T_SWITCH;
 	write_unlock(&journal->j_state_lock);
 
@@ -817,7 +804,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	commit_transaction->t_state = T_COMMIT_DFLUSH;
 	write_unlock(&journal->j_state_lock);
 
-	/* 
+	/*
 	 * If the journal is not located on the file system device,
 	 * then we must flush the file system device before we issue
 	 * the commit record
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 6a3caedd2285..8e2f8275a253 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -449,7 +449,7 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
 	}
 
 	/* OK, account for the buffers that this operation expects to
-	 * use and add the handle to the running transaction. 
+	 * use and add the handle to the running transaction.
 	 */
 	update_t_max_wait(transaction, ts);
 	handle->h_transaction = transaction;
@@ -836,6 +836,35 @@ int jbd2_journal_restart(handle_t *handle, int nblocks)
 }
 EXPORT_SYMBOL(jbd2_journal_restart);
 
+/*
+ * Waits for any outstanding t_updates to finish.
+ * This is called with write j_state_lock held.
+ */
+void jbd2_journal_wait_updates(journal_t *journal)
+{
+	transaction_t *commit_transaction = journal->j_running_transaction;
+
+	if (!commit_transaction)
+		return;
+
+	spin_lock(&commit_transaction->t_handle_lock);
+	while (atomic_read(&commit_transaction->t_updates)) {
+		DEFINE_WAIT(wait);
+
+		prepare_to_wait(&journal->j_wait_updates, &wait,
+					TASK_UNINTERRUPTIBLE);
+		if (atomic_read(&commit_transaction->t_updates)) {
+			spin_unlock(&commit_transaction->t_handle_lock);
+			write_unlock(&journal->j_state_lock);
+			schedule();
+			write_lock(&journal->j_state_lock);
+			spin_lock(&commit_transaction->t_handle_lock);
+		}
+		finish_wait(&journal->j_wait_updates, &wait);
+	}
+	spin_unlock(&commit_transaction->t_handle_lock);
+}
+
 /**
  * jbd2_journal_lock_updates () - establish a transaction barrier.
  * @journal:  Journal to establish a barrier on.
@@ -863,27 +892,9 @@ void jbd2_journal_lock_updates(journal_t *journal)
 		write_lock(&journal->j_state_lock);
 	}
 
-	/* Wait until there are no running updates */
-	while (1) {
-		transaction_t *transaction = journal->j_running_transaction;
-
-		if (!transaction)
-			break;
+	/* Wait until there are no running t_updates */
+	jbd2_journal_wait_updates(journal);
 
-		spin_lock(&transaction->t_handle_lock);
-		prepare_to_wait(&journal->j_wait_updates, &wait,
-				TASK_UNINTERRUPTIBLE);
-		if (!atomic_read(&transaction->t_updates)) {
-			spin_unlock(&transaction->t_handle_lock);
-			finish_wait(&journal->j_wait_updates, &wait);
-			break;
-		}
-		spin_unlock(&transaction->t_handle_lock);
-		write_unlock(&journal->j_state_lock);
-		schedule();
-		finish_wait(&journal->j_wait_updates, &wait);
-		write_lock(&journal->j_state_lock);
-	}
 	write_unlock(&journal->j_state_lock);
 
 	/*
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index f76598265896..575c3057a98a 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -594,7 +594,7 @@ struct transaction_s
 	 */
 	unsigned long		t_log_start;
 
-	/* 
+	/*
 	 * Number of buffers on the t_buffers list [j_list_lock, no locks
 	 * needed for jbd2 thread]
 	 */
@@ -1538,6 +1538,8 @@ extern int	 jbd2_journal_flush(journal_t *journal, unsigned int flags);
 extern void	 jbd2_journal_lock_updates (journal_t *);
 extern void	 jbd2_journal_unlock_updates (journal_t *);
 
+void jbd2_journal_wait_updates(journal_t *);
+
 extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
 				struct block_device *fs_dev,
 				unsigned long long start, int len, int bsize);
-- 
2.31.1

Re: [PATCHv2 0/5] ext4/jbd2: inline_data fixes and minor cleanups

[Theodore Ts'o]

On Mon, 17 Jan 2022 17:41:46 +0530, Ritesh Harjani wrote:
> Please find v2 of the inline_data fixes and some minor cleanups found during
> code review.
> 
> I have dropped patch-6 in v2 which was removing use of t_handle_lock (spinlock)
> from within jbd2_journal_wait_updates(). Based on Jan comments, I feel we can
> push that as killing of t_handle_lock into a separate series (which will be on
> top of this).
> 
> [...]

Applied, thanks!

[1/5] ext4: Fix error handling in ext4_restore_inline_data()
      commit: 2fdd85005f708691a64270ecb67d98191d668c4c
[2/5] ext4: Remove redundant max inline_size check in ext4_da_write_inline_data_begin()
      commit: c7fc77e512a432bba754f969c4eb72b33cda3431
[3/5] ext4: Fix error handling in ext4_fc_record_modified_inode()
      commit: 6dcee78ea266fb736a3357c2e04d81ee7ec7b6e4
[4/5] jbd2: Cleanup unused functions declarations from jbd2.h
      commit: 16263b9820b0d40c778c8ee867f853d3fe638f37
[5/5] jbd2: Refactor wait logic for transaction updates into a common function
      commit: b0544c1f23ddeabd89480d842867ca1c6894e021

Best regards,
-- 
Theodore Ts'o <tytso@mit.edu>