Patch 1 fixes reusing stale buffer heads from last failed mounting.
Patch 2~4 reconstructs 'j_format_version' initialization and checking
in loading process.
v1->v2:
Adopt suggestions from Tudor, add fix tag and corrupt 'stable' field
in patch 1.
Reserve empty lines in patch 4.
Zhang Yi (4):
jbd2: remove unused feature macros
jbd2: switch to check format version in superblock directly
jbd2: factor out journal initialization from journal_get_superblock()
jbd2: remove j_format_version
Zhihao Cheng (1):
ext4: Fix reusing stale buffer heads from last failed mounting
fs/ext4/super.c | 15 +++++++------
fs/jbd2/journal.c | 53 +++++++++++++++++---------------------------
include/linux/jbd2.h | 33 ++++++++++++---------------
3 files changed, 42 insertions(+), 59 deletions(-)
--
2.31.1
From: Zhang Yi <[email protected]>
JBD2_HAS_[IN|RO_]COMPAT_FEATURE macros are no longer used, just remove
them.
Signed-off-by: Zhang Yi <[email protected]>
Signed-off-by: Zhihao Cheng <[email protected]>
---
include/linux/jbd2.h | 11 -----------
1 file changed, 11 deletions(-)
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 5962072a4b19..ad7bb6861143 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -274,17 +274,6 @@ typedef struct journal_superblock_s
/* 0x0400 */
} journal_superblock_t;
-/* Use the jbd2_{has,set,clear}_feature_* helpers; these will be removed */
-#define JBD2_HAS_COMPAT_FEATURE(j,mask) \
- ((j)->j_format_version >= 2 && \
- ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
-#define JBD2_HAS_RO_COMPAT_FEATURE(j,mask) \
- ((j)->j_format_version >= 2 && \
- ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
-#define JBD2_HAS_INCOMPAT_FEATURE(j,mask) \
- ((j)->j_format_version >= 2 && \
- ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
-
#define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001
#define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001
--
2.31.1
Following process makes ext4 load stale buffer heads from last failed
mounting in a new mounting operation:
mount_bdev
ext4_fill_super
| ext4_load_and_init_journal
| ext4_load_journal
| jbd2_journal_load
| load_superblock
| journal_get_superblock
| set_buffer_verified(bh) // buffer head is verified
| jbd2_journal_recover // failed caused by EIO
| goto failed_mount3a // skip 'sb->s_root' initialization
deactivate_locked_super
kill_block_super
generic_shutdown_super
if (sb->s_root)
// false, skip ext4_put_super->invalidate_bdev->
// invalidate_mapping_pages->mapping_evict_folio->
// filemap_release_folio->try_to_free_buffers, which
// cannot drop buffer head.
blkdev_put
blkdev_put_whole
if (atomic_dec_and_test(&bdev->bd_openers))
// false, systemd-udev happens to open the device. Then
// blkdev_flush_mapping->kill_bdev->truncate_inode_pages->
// truncate_inode_folio->truncate_cleanup_folio->
// folio_invalidate->block_invalidate_folio->
// filemap_release_folio->try_to_free_buffers will be skipped,
// dropping buffer head is missed again.
Second mount:
ext4_fill_super
ext4_load_and_init_journal
ext4_load_journal
ext4_get_journal
jbd2_journal_init_inode
journal_init_common
bh = getblk_unmovable
bh = __find_get_block // Found stale bh in last failed mounting
journal->j_sb_buffer = bh
jbd2_journal_load
load_superblock
journal_get_superblock
if (buffer_verified(bh))
// true, skip journal->j_format_version = 2, value is 0
jbd2_journal_recover
do_one_pass
next_log_block += count_tags(journal, bh)
// According to journal_tag_bytes(), 'tag_bytes' calculating is
// affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3()
// returns false because 'j->j_format_version >= 2' is not true,
// then we get wrong next_log_block. The do_one_pass may exit
// early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'.
The filesystem is corrupted here, journal is partially replayed, and
new journal sequence number actually is already used by last mounting.
The invalidate_bdev() can drop all buffer heads even racing with bare
reading block device(eg. systemd-udev), so we can fix it by invalidating
bdev in error handling path in __ext4_fill_super().
Fetch a reproducer in [Link].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171
Fixes: 25ed6e8a54df ("jbd2: enable journal clients to enable v2 checksumming")
Cc: [email protected] # v3.5
Signed-off-by: Zhihao Cheng <[email protected]>
---
fs/ext4/super.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 88f7b8a88c76..7e990637bc48 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1126,6 +1126,12 @@ static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
struct block_device *bdev;
bdev = sbi->s_journal_bdev;
if (bdev) {
+ /*
+ * Invalidate the journal device's buffers. We don't want them
+ * floating about in memory - the physical journal device may
+ * hotswapped, and it breaks the `ro-after' testing code.
+ */
+ invalidate_bdev(bdev);
ext4_blkdev_put(bdev);
sbi->s_journal_bdev = NULL;
}
@@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
sync_blockdev(sb->s_bdev);
invalidate_bdev(sb->s_bdev);
- if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
- /*
- * Invalidate the journal device's buffers. We don't want them
- * floating about in memory - the physical journal device may
- * hotswapped, and it breaks the `ro-after' testing code.
- */
+ if (sbi->s_journal_bdev) {
sync_blockdev(sbi->s_journal_bdev);
- invalidate_bdev(sbi->s_journal_bdev);
ext4_blkdev_remove(sbi);
}
@@ -5610,6 +5610,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
brelse(sbi->s_sbh);
ext4_blkdev_remove(sbi);
out_fail:
+ invalidate_bdev(sb->s_bdev);
sb->s_fs_info = NULL;
return err ? err : ret;
}
--
2.31.1
From: Zhang Yi <[email protected]>
We should only check and set extented features if journal format version
is 2, and now we check the in memory copy of the superblock
'journal->j_format_version', which relys on the parameter initialization
sequence, switch to use the h_blocktype in superblock cloud be more
clear.
Signed-off-by: Zhang Yi <[email protected]>
Signed-off-by: Zhihao Cheng <[email protected]>
---
fs/jbd2/journal.c | 16 +++++++---------
include/linux/jbd2.h | 17 ++++++++++++++---
2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index e80c781731f8..b991d5c21d16 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2059,10 +2059,12 @@ int jbd2_journal_load(journal_t *journal)
return err;
sb = journal->j_superblock;
- /* If this is a V2 superblock, then we have to check the
- * features flags on it. */
- if (journal->j_format_version >= 2) {
+ /*
+ * If this is a V2 superblock, then we have to check the
+ * features flags on it.
+ */
+ if (jbd2_format_support_feature(journal)) {
if ((sb->s_feature_ro_compat &
~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
(sb->s_feature_incompat &
@@ -2224,7 +2226,7 @@ int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
if (journal->j_format_version == 0 &&
journal_get_superblock(journal) != 0)
return 0;
- if (journal->j_format_version == 1)
+ if (!jbd2_format_support_feature(journal))
return 0;
sb = journal->j_superblock;
@@ -2254,11 +2256,7 @@ int jbd2_journal_check_available_features(journal_t *journal, unsigned long comp
if (!compat && !ro && !incompat)
return 1;
- /* We can support any known requested features iff the
- * superblock is in version 2. Otherwise we fail to support any
- * extended sb features. */
-
- if (journal->j_format_version != 2)
+ if (!jbd2_format_support_feature(journal))
return 0;
if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index ad7bb6861143..7095c0f17ad0 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1305,11 +1305,22 @@ struct journal_s
rwsem_release(&j->j_trans_commit_map, _THIS_IP_); \
} while (0)
+/*
+ * We can support any known requested features iff the
+ * superblock is not in version 1. Otherwise we fail to support any
+ * extended sb features.
+ */
+static inline bool jbd2_format_support_feature(journal_t *j)
+{
+ return j->j_superblock->s_header.h_blocktype !=
+ cpu_to_be32(JBD2_SUPERBLOCK_V1);
+}
+
/* journal feature predicate functions */
#define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
- return ((j)->j_format_version >= 2 && \
+ return (jbd2_format_support_feature(j) && \
((j)->j_superblock->s_feature_compat & \
cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname)) != 0); \
} \
@@ -1327,7 +1338,7 @@ static inline void jbd2_clear_feature_##name(journal_t *j) \
#define JBD2_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
- return ((j)->j_format_version >= 2 && \
+ return (jbd2_format_support_feature(j) && \
((j)->j_superblock->s_feature_ro_compat & \
cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname)) != 0); \
} \
@@ -1345,7 +1356,7 @@ static inline void jbd2_clear_feature_##name(journal_t *j) \
#define JBD2_FEATURE_INCOMPAT_FUNCS(name, flagname) \
static inline bool jbd2_has_feature_##name(journal_t *j) \
{ \
- return ((j)->j_format_version >= 2 && \
+ return (jbd2_format_support_feature(j) && \
((j)->j_superblock->s_feature_incompat & \
cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname)) != 0); \
} \
--
2.31.1
From: Zhang Yi <[email protected]>
journal->j_format_version is no longer used, remove it.
Signed-off-by: Zhang Yi <[email protected]>
Signed-off-by: Zhihao Cheng <[email protected]>
---
fs/jbd2/journal.c | 9 ---------
include/linux/jbd2.h | 5 -----
2 files changed, 14 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f99c46d880b2..c19cdd402a5f 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2003,15 +2003,6 @@ static int load_superblock(journal_t *journal)
sb = journal->j_superblock;
- switch (be32_to_cpu(sb->s_header.h_blocktype)) {
- case JBD2_SUPERBLOCK_V1:
- journal->j_format_version = 1;
- break;
- case JBD2_SUPERBLOCK_V2:
- journal->j_format_version = 2;
- break;
- }
-
journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
journal->j_tail = be32_to_cpu(sb->s_start);
journal->j_first = be32_to_cpu(sb->s_first);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 7095c0f17ad0..b7c79f68f7ca 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -792,11 +792,6 @@ struct journal_s
*/
journal_superblock_t *j_superblock;
- /**
- * @j_format_version: Version of the superblock format.
- */
- int j_format_version;
-
/**
* @j_state_lock: Protect the various scalars in the journal.
*/
--
2.31.1
From: Zhang Yi <[email protected]>
Current journal_get_superblock() couple journal superblock checking and
partial journal initialization, factor out initialization part from it
to make things clear.
Signed-off-by: Zhang Yi <[email protected]>
Signed-off-by: Zhihao Cheng <[email protected]>
---
fs/jbd2/journal.c | 46 ++++++++++++++++++++++------------------------
1 file changed, 22 insertions(+), 24 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index b991d5c21d16..f99c46d880b2 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1922,21 +1922,13 @@ static int journal_get_superblock(journal_t *journal)
goto out;
}
- switch(be32_to_cpu(sb->s_header.h_blocktype)) {
- case JBD2_SUPERBLOCK_V1:
- journal->j_format_version = 1;
- break;
- case JBD2_SUPERBLOCK_V2:
- journal->j_format_version = 2;
- break;
- default:
+ if (be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V1 &&
+ be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V2) {
printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
goto out;
}
- if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
- journal->j_total_len = be32_to_cpu(sb->s_maxlen);
- else if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
+ if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
printk(KERN_WARNING "JBD2: journal file too short\n");
goto out;
}
@@ -1979,25 +1971,14 @@ static int journal_get_superblock(journal_t *journal)
journal->j_chksum_driver = NULL;
goto out;
}
- }
-
- if (jbd2_journal_has_csum_v2or3(journal)) {
/* Check superblock checksum */
if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
printk(KERN_ERR "JBD2: journal checksum error\n");
err = -EFSBADCRC;
goto out;
}
-
- /* Precompute checksum seed for all metadata */
- journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
- sizeof(sb->s_uuid));
}
-
- journal->j_revoke_records_per_block =
- journal_revoke_records_per_block(journal);
set_buffer_verified(bh);
-
return 0;
out:
@@ -2022,12 +2003,30 @@ static int load_superblock(journal_t *journal)
sb = journal->j_superblock;
+ switch (be32_to_cpu(sb->s_header.h_blocktype)) {
+ case JBD2_SUPERBLOCK_V1:
+ journal->j_format_version = 1;
+ break;
+ case JBD2_SUPERBLOCK_V2:
+ journal->j_format_version = 2;
+ break;
+ }
+
journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
journal->j_tail = be32_to_cpu(sb->s_start);
journal->j_first = be32_to_cpu(sb->s_first);
journal->j_errno = be32_to_cpu(sb->s_errno);
journal->j_last = be32_to_cpu(sb->s_maxlen);
+ if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
+ journal->j_total_len = be32_to_cpu(sb->s_maxlen);
+ /* Precompute checksum seed for all metadata */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
+ sizeof(sb->s_uuid));
+ journal->j_revoke_records_per_block =
+ journal_revoke_records_per_block(journal);
+
if (jbd2_has_feature_fast_commit(journal)) {
journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
@@ -2223,8 +2222,7 @@ int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
if (!compat && !ro && !incompat)
return 1;
/* Load journal superblock if it is not loaded yet. */
- if (journal->j_format_version == 0 &&
- journal_get_superblock(journal) != 0)
+ if (journal_get_superblock(journal))
return 0;
if (!jbd2_format_support_feature(journal))
return 0;
--
2.31.1
On Mon 13-03-23 21:20:17, Zhihao Cheng wrote:
> Following process makes ext4 load stale buffer heads from last failed
> mounting in a new mounting operation:
> mount_bdev
> ext4_fill_super
> | ext4_load_and_init_journal
> | ext4_load_journal
> | jbd2_journal_load
> | load_superblock
> | journal_get_superblock
> | set_buffer_verified(bh) // buffer head is verified
> | jbd2_journal_recover // failed caused by EIO
> | goto failed_mount3a // skip 'sb->s_root' initialization
> deactivate_locked_super
> kill_block_super
> generic_shutdown_super
> if (sb->s_root)
> // false, skip ext4_put_super->invalidate_bdev->
> // invalidate_mapping_pages->mapping_evict_folio->
> // filemap_release_folio->try_to_free_buffers, which
> // cannot drop buffer head.
> blkdev_put
> blkdev_put_whole
> if (atomic_dec_and_test(&bdev->bd_openers))
> // false, systemd-udev happens to open the device. Then
> // blkdev_flush_mapping->kill_bdev->truncate_inode_pages->
> // truncate_inode_folio->truncate_cleanup_folio->
> // folio_invalidate->block_invalidate_folio->
> // filemap_release_folio->try_to_free_buffers will be skipped,
> // dropping buffer head is missed again.
>
> Second mount:
> ext4_fill_super
> ext4_load_and_init_journal
> ext4_load_journal
> ext4_get_journal
> jbd2_journal_init_inode
> journal_init_common
> bh = getblk_unmovable
> bh = __find_get_block // Found stale bh in last failed mounting
> journal->j_sb_buffer = bh
> jbd2_journal_load
> load_superblock
> journal_get_superblock
> if (buffer_verified(bh))
> // true, skip journal->j_format_version = 2, value is 0
> jbd2_journal_recover
> do_one_pass
> next_log_block += count_tags(journal, bh)
> // According to journal_tag_bytes(), 'tag_bytes' calculating is
> // affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3()
> // returns false because 'j->j_format_version >= 2' is not true,
> // then we get wrong next_log_block. The do_one_pass may exit
> // early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'.
>
> The filesystem is corrupted here, journal is partially replayed, and
> new journal sequence number actually is already used by last mounting.
>
> The invalidate_bdev() can drop all buffer heads even racing with bare
> reading block device(eg. systemd-udev), so we can fix it by invalidating
> bdev in error handling path in __ext4_fill_super().
>
> Fetch a reproducer in [Link].
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171
> Fixes: 25ed6e8a54df ("jbd2: enable journal clients to enable v2 checksumming")
> Cc: [email protected] # v3.5
> Signed-off-by: Zhihao Cheng <[email protected]>
...
> @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
>
> sync_blockdev(sb->s_bdev);
> invalidate_bdev(sb->s_bdev);
> - if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
> - /*
> - * Invalidate the journal device's buffers. We don't want them
> - * floating about in memory - the physical journal device may
> - * hotswapped, and it breaks the `ro-after' testing code.
> - */
> + if (sbi->s_journal_bdev) {
> sync_blockdev(sbi->s_journal_bdev);
> - invalidate_bdev(sbi->s_journal_bdev);
> ext4_blkdev_remove(sbi);
> }
Hum, but this will invalidate bhs only if journal is stored on a block
device. If journal is in the inode (the common case), we won't invalidate
anything (sbi->s_journal_bdev is NULL) and the same problem can happen?
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Mon 13-03-23 21:20:18, Zhihao Cheng wrote:
> From: Zhang Yi <[email protected]>
>
> JBD2_HAS_[IN|RO_]COMPAT_FEATURE macros are no longer used, just remove
> them.
>
> Signed-off-by: Zhang Yi <[email protected]>
> Signed-off-by: Zhihao Cheng <[email protected]>
I gave you my Reviewed-by on this patch (and a few others in this series).
Why didn't you include it?
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Tue 14-03-23 20:01:46, Zhihao Cheng wrote:
> 在 2023/3/14 19:33, Jan Kara 写道:
> Hi Jan,
>
> >
> > > @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
> > > sync_blockdev(sb->s_bdev);
> > > invalidate_bdev(sb->s_bdev);
>
> For journal in the inode case, journal bhs come from block device, which
> means buffers will be dropped after this line 'invalidate_bdev(sb->s_bdev)'
> being executed.
Right, I've missed that. But then why do you remove the sbi->s_journal_bdev
!= sb->s_bdev condition below?
> > > - if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
> > > - /*
> > > - * Invalidate the journal device's buffers. We don't want them
> > > - * floating about in memory - the physical journal device may
> > > - * hotswapped, and it breaks the `ro-after' testing code.
> > > - */
> > > + if (sbi->s_journal_bdev) {
> > > sync_blockdev(sbi->s_journal_bdev);
> > > - invalidate_bdev(sbi->s_journal_bdev);
> > > ext4_blkdev_remove(sbi);
> > > }
> > > Hum, but this will invalidate bhs only if journal is stored on a block
> > device. If journal is in the inode (the common case), we won't invalidate
> > anything (sbi->s_journal_bdev is NULL) and the same problem can happen?
> >
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
?? 2023/3/14 19:33, Jan Kara д??:
Hi Jan,
>
>> @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
>>
>> sync_blockdev(sb->s_bdev);
>> invalidate_bdev(sb->s_bdev);
For journal in the inode case, journal bhs come from block device, which
means buffers will be dropped after this line
'invalidate_bdev(sb->s_bdev)' being executed.
>> - if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) {
>> - /*
>> - * Invalidate the journal device's buffers. We don't want them
>> - * floating about in memory - the physical journal device may
>> - * hotswapped, and it breaks the `ro-after' testing code.
>> - */
>> + if (sbi->s_journal_bdev) {
>> sync_blockdev(sbi->s_journal_bdev);
>> - invalidate_bdev(sbi->s_journal_bdev);
>> ext4_blkdev_remove(sbi);
>> }
> > Hum, but this will invalidate bhs only if journal is stored on a block
> device. If journal is in the inode (the common case), we won't invalidate
> anything (sbi->s_journal_bdev is NULL) and the same problem can happen?
>
Hi Jan,
> On Mon 13-03-23 21:20:18, Zhihao Cheng wrote:
>> From: Zhang Yi <[email protected]>
>>
>> JBD2_HAS_[IN|RO_]COMPAT_FEATURE macros are no longer used, just remove
>> them.
>>
>> Signed-off-by: Zhang Yi <[email protected]>
>> Signed-off-by: Zhihao Cheng <[email protected]>
>
> I gave you my Reviewed-by on this patch (and a few others in this series).
> Why didn't you include it?
>
Sorry, my fault. Will add in v3.
> On Tue 14-03-23 20:01:46, Zhihao Cheng wrote:
>> 在 2023/3/14 19:33, Jan Kara 写道:
>> Hi Jan,
>>
>>>
>>>> @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
>>>> sync_blockdev(sb->s_bdev);
>>>> invalidate_bdev(sb->s_bdev);
>>
>> For journal in the inode case, journal bhs come from block device, which
>> means buffers will be dropped after this line 'invalidate_bdev(sb->s_bdev)'
>> being executed.
>
> Right, I've missed that. But then why do you remove the sbi->s_journal_bdev
> != sb->s_bdev condition below?
>
I think 'sbi->s_journal_bdev != sb->s_bdev' always becomes true if
sbi->s_journal_bdev exists.
mount_bdev
fmode_t mode = FMODE_READ | FMODE_EXCL
bdev_a = blkdev_get_by_path(dev_name, mode, fs_type)
mount_bdev->ext4_fill_super->ext4_load_and_init_journal->ext4_load_journal->ext4_get_dev_journal:
bdev_b = ext4_blkdev_get(j_dev, sb)
bdev_b = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb)
EXT4_SB(sb)->s_journal_bdev = bdev_b
bdev_a cannot be bdev_b, because bd_prepare_to_claim() makes sure the
same block device cannot be openned twice with mode 'FMODE_EXCL'.
On Tue 14-03-23 20:31:43, Zhihao Cheng wrote:
> > On Tue 14-03-23 20:01:46, Zhihao Cheng wrote:
> > > 在 2023/3/14 19:33, Jan Kara 写道:
> > > Hi Jan,
> > >
> > > >
> > > > > @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
> > > > > sync_blockdev(sb->s_bdev);
> > > > > invalidate_bdev(sb->s_bdev);
> > >
> > > For journal in the inode case, journal bhs come from block device, which
> > > means buffers will be dropped after this line 'invalidate_bdev(sb->s_bdev)'
> > > being executed.
> >
> > Right, I've missed that. But then why do you remove the sbi->s_journal_bdev
> > != sb->s_bdev condition below?
> >
>
> I think 'sbi->s_journal_bdev != sb->s_bdev' always becomes true if
> sbi->s_journal_bdev exists.
OK, fair point. But please move this cleanup into a separate commit with
this justification. Thanks!
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
> OK, fair point. But please move this cleanup into a separate commit with
> this justification. Thanks!
OK, I will split it from patch 1 in v3.