[PATCH AUTOSEL 5.4 103/108] ext4: check for non-zero journal inum in ext4_calculate_overhead

[PATCH AUTOSEL 5.4 103/108] ext4: check for non-zero journal inum in ext4_calculate_overhead

[Sasha Levin]

From: Ritesh Harjani <riteshh@linux.ibm.com>

[ Upstream commit f1eec3b0d0a849996ebee733b053efa71803dad5 ]

While calculating overhead for internal journal, also check
that j_inum shouldn't be 0. Otherwise we get below error with
xfstests generic/050 with external journal (XXX_LOGDEV config) enabled.

It could be simply reproduced with loop device with an external journal
and marking blockdev as RO before mounting.

[ 3337.146838] EXT4-fs error (device pmem1p2): ext4_get_journal_inode:4634: comm mount: inode #0: comm mount: iget: illegal inode #
------------[ cut here ]------------
generic_make_request: Trying to write to read-only block-device pmem1p2 (partno 2)
WARNING: CPU: 107 PID: 115347 at block/blk-core.c:788 generic_make_request_checks+0x6b4/0x7d0
CPU: 107 PID: 115347 Comm: mount Tainted: G             L   --------- -t - 4.18.0-167.el8.ppc64le #1
NIP:  c0000000006f6d44 LR: c0000000006f6d40 CTR: 0000000030041dd4
<...>
NIP [c0000000006f6d44] generic_make_request_checks+0x6b4/0x7d0
LR [c0000000006f6d40] generic_make_request_checks+0x6b0/0x7d0
<...>
Call Trace:
generic_make_request_checks+0x6b0/0x7d0 (unreliable)
generic_make_request+0x3c/0x420
submit_bio+0xd8/0x200
submit_bh_wbc+0x1e8/0x250
__sync_dirty_buffer+0xd0/0x210
ext4_commit_super+0x310/0x420 [ext4]
__ext4_error+0xa4/0x1e0 [ext4]
__ext4_iget+0x388/0xe10 [ext4]
ext4_get_journal_inode+0x40/0x150 [ext4]
ext4_calculate_overhead+0x5a8/0x610 [ext4]
ext4_fill_super+0x3188/0x3260 [ext4]
mount_bdev+0x778/0x8f0
ext4_mount+0x28/0x50 [ext4]
mount_fs+0x74/0x230
vfs_kern_mount.part.6+0x6c/0x250
do_mount+0x2fc/0x1280
sys_mount+0x158/0x180
system_call+0x5c/0x70
EXT4-fs (pmem1p2): no journal found
EXT4-fs (pmem1p2): can't get journal size
EXT4-fs (pmem1p2): mounted filesystem without journal. Opts: dax,norecovery

Fixes: 3c816ded78bb ("ext4: use journal inode to determine journal overhead")
Reported-by: Harish Sriram <harish@linux.ibm.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200316093038.25485-1-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/super.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8bd806a03a90c..ce730d8e08685 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3561,7 +3561,8 @@ int ext4_calculate_overhead(struct super_block *sb)
 	 */
 	if (sbi->s_journal && !sbi->journal_bdev)
 		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
-	else if (ext4_has_feature_journal(sb) && !sbi->s_journal) {
+	else if (ext4_has_feature_journal(sb) && !sbi->s_journal && j_inum) {
+		/* j_inum for internal journal is non-zero */
 		j_inode = ext4_get_journal_inode(sb, j_inum);
 		if (j_inode) {
 			j_blocks = j_inode->i_size >> sb->s_blocksize_bits;
-- 
2.20.1

[PATCH AUTOSEL 5.4 104/108] ext4: avoid ENOSPC when avoiding to reuse recently deleted inodes

[Sasha Levin]

From: Jan Kara <jack@suse.cz>

[ Upstream commit d05466b27b19af8e148376590ed54d289b607f0a ]

When ext4 is running on a filesystem without a journal, it tries not to
reuse recently deleted inodes to provide better chances for filesystem
recovery in case of crash. However this logic forbids reuse of freed
inodes for up to 5 minutes and especially for filesystems with smaller
number of inodes can lead to ENOSPC errors returned when allocating new
inodes.

Fix the problem by allowing to reuse recently deleted inode if there's
no other inode free in the scanned range.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200318121317.31941-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/ialloc.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a6288730210e8..bfcf15beb87ad 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -709,21 +709,34 @@ static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
 			  struct buffer_head *bitmap, unsigned long *ino)
 {
+	bool check_recently_deleted = EXT4_SB(sb)->s_journal == NULL;
+	unsigned long recently_deleted_ino = EXT4_INODES_PER_GROUP(sb);
+
 next:
 	*ino = ext4_find_next_zero_bit((unsigned long *)
 				       bitmap->b_data,
 				       EXT4_INODES_PER_GROUP(sb), *ino);
 	if (*ino >= EXT4_INODES_PER_GROUP(sb))
-		return 0;
+		goto not_found;
 
-	if ((EXT4_SB(sb)->s_journal == NULL) &&
-	    recently_deleted(sb, group, *ino)) {
+	if (check_recently_deleted && recently_deleted(sb, group, *ino)) {
+		recently_deleted_ino = *ino;
 		*ino = *ino + 1;
 		if (*ino < EXT4_INODES_PER_GROUP(sb))
 			goto next;
-		return 0;
+		goto not_found;
 	}
-
+	return 1;
+not_found:
+	if (recently_deleted_ino >= EXT4_INODES_PER_GROUP(sb))
+		return 0;
+	/*
+	 * Not reusing recently deleted inodes is mostly a preference. We don't
+	 * want to report ENOSPC or skew allocation patterns because of that.
+	 * So return even recently deleted inode if we could find better in the
+	 * given range.
+	 */
+	*ino = recently_deleted_ino;
 	return 1;
 }
 
-- 
2.20.1