ext4: avoid deadlock in fs reclaim with page writeback

Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This

ext4: avoid deadlock in fs reclaim with page writeback

Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:

CPU0 CPU1

ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever

Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.

Reported-by: syzbot+6898da502aef574c5f8a@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000004c66b405fa108e27@google.com
Fixes: c8585c6fcaf2 ("ext4: fix races between changing inode journal mode and ext4_writepages")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230504124723.20205-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: allow ext4_get_group_info() to fail

Previously, ext4_get_group_info() would treat an invalid group number
as BUG(), since in theory it should never happen. However, if a
malicious attaker (or

ext4: allow ext4_get_group_info() to fail

Previously, ext4_get_group_info() would treat an invalid group number
as BUG(), since in theory it should never happen. However, if a
malicious attaker (or fuzzer) modifies the superblock via the block
device while it is the file system is mounted, it is possible for
s_first_data_block to get set to a very large number. In that case,
when calculating the block group of some block number (such as the
starting block of a preallocation region), could result in an
underflow and very large block group number. Then the BUG_ON check in
ext4_get_group_info() would fire, resutling in a denial of service
attack that can be triggered by root or someone with write access to
the block device.

For a quality of implementation perspective, it's best that even if
the system administrator does something that they shouldn't, that it
will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info()
will call ext4_error and return NULL. We also add fallback code in
all of the callers of ext4_get_group_info() that it might NULL.

Also, since ext4_get_group_info() was already borderline to be an
inline function, un-inline it. The results in a next reduction of the
compiled text size of ext4 by roughly 2k.

Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230430154311.579720-2-tytso@mit.edu
Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

show more ...

ext4: Add a uapi header for ext4 userspace APIs

Create a uapi header include/uapi/linux/ext4.h, move the ioctls and
associated data structures to the uapi header, and include it from
fs/ext4/ext4.h.

ext4: Add a uapi header for ext4 userspace APIs

Create a uapi header include/uapi/linux/ext4.h, move the ioctls and
associated data structures to the uapi header, and include it from
fs/ext4/ext4.h.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/680175260970d977d16b5cc7e7606483ec99eb63.1680402881.git.josh@joshtriplett.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: Simplify handling of journalled data in ext4_bmap()

Now that ext4_writepages() gets journalled data into its final location
we just use filemap_write_and_wait() instead of special handling of

ext4: Simplify handling of journalled data in ext4_bmap()

Now that ext4_writepages() gets journalled data into its final location
we just use filemap_write_and_wait() instead of special handling of
journalled data in ext4_bmap(). We can also drop EXT4_STATE_JDATA flag
as it is not used anymore.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230329154950.19720-11-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: Convert ext4_mpage_readpages() to work on folios

This definitely doesn't include support for large folios; there
are all kinds of assumptions about the number of buffers attached
to a folio.

ext4: Convert ext4_mpage_readpages() to work on folios

This definitely doesn't include support for large folios; there
are all kinds of assumptions about the number of buffers attached
to a folio. But it does remove several calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20230324180129.1220691-24-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: Convert ext4_readpage_inline() to take a folio

Use the folio API in this function, saves a few calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-

ext4: Convert ext4_readpage_inline() to take a folio

Use the folio API in this function, saves a few calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-10-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: Convert ext4_bio_write_page() to ext4_bio_write_folio()

The only caller now has a folio so pass it in directly and avoid the call
to page_folio() at the beginning.

Signed-off-by: Matthew Wilc

ext4: Convert ext4_bio_write_page() to ext4_bio_write_folio()

The only caller now has a folio so pass it in directly and avoid the call
to page_folio() at the beginning.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-9-willy@infradead.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: Remove the logic to trim inode PAs

Earlier, inode PAs were stored in a linked list. This caused a need to
periodically trim the list down inorder to avoid growing it to a very
large size, as t

ext4: Remove the logic to trim inode PAs

Earlier, inode PAs were stored in a linked list. This caused a need to
periodically trim the list down inorder to avoid growing it to a very
large size, as this would severly affect performance during list
iteration.

Recent patches changed this list to an rbtree, and since the tree scales
up much better, we no longer need to have the trim functionality, hence
remove it.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/c409addceaa3ade4b40328e28e3b54b2f259689e.1679731817.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list

Currently, the kernel uses i_prealloc_list to hold all the inode
preallocations. This is known to cause degradation in performance in

ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list

Currently, the kernel uses i_prealloc_list to hold all the inode
preallocations. This is known to cause degradation in performance in
workloads which perform large number of sparse writes on a single file.
This is mainly because functions like ext4_mb_normalize_request() and
ext4_mb_use_preallocated() iterate over this complete list, resulting in
slowdowns when large number of PAs are present.

Patch 27bc446e2 partially fixed this by enforcing a limit of 512 for
the inode preallocation list and adding logic to continually trim the
list if it grows above the threshold, however our testing revealed that
a hardcoded value is not suitable for all kinds of workloads.

To optimize this, add an rbtree to the inode and hold the inode
preallocations in this rbtree. This will make iterating over inode PAs
faster and scale much better than a linked list. Additionally, we also
had to remove the LRU logic that was added during trimming of the list
(in ext4_mb_release_context()) as it will add extra overhead in rbtree.
The discards now happen in the lowest-logical-offset-first order.

** Locking notes **

With the introduction of rbtree to maintain inode PAs, we can't use RCU
to walk the tree for searching since it can result in partial traversals
which might miss some nodes(or entire subtrees) while discards happen
in parallel (which happens under a lock). Hence this patch converts the
ei->i_prealloc_lock spin_lock to rw_lock.

Almost all the codepaths that read/modify the PA rbtrees are protected
by the higher level inode->i_data_sem (except
ext4_mb_discard_group_preallocations() and ext4_clear_inode()) IIUC, the
only place we need lock protection is when one thread is reading
"searching" the PA rbtree (earlier protected under rcu_read_lock()) and
another is "deleting" the PAs in ext4_mb_discard_group_preallocations()
function (which iterates all the PAs using the grp->bb_prealloc_list and
deletes PAs from the tree without taking any inode lock (i_data_sem)).

So, this patch converts all rcu_read_lock/unlock() paths for inode list
PA to use read_lock() and all places where we were using
ei->i_prealloc_lock spinlock will now be using write_lock().

Note that this makes the fast path (searching of the right PA e.g.
ext4_mb_use_preallocated() or ext4_mb_normalize_request()), now use
read_lock() instead of rcu_read_lock/unlock(). Ths also will now block
due to slow discard path (ext4_mb_discard_group_preallocations()) which
uses write_lock().

But this is not as bad as it looks. This is because -

1. The slow path only occurs when the normal allocation failed and we
can say that we are low on disk space. One can argue this scenario
won't be much frequent.

2. ext4_mb_discard_group_preallocations(), locks and unlocks the rwlock
for deleting every individual PA. This gives enough opportunity for
the fast path to acquire the read_lock for searching the PA inode
list.

Suggested-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/4137bce8f6948fedd8bae134dabae24acfe699c6.1679731817.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: remove unused group parameter in ext4_block_bitmap_csum_set

Remove unused group parameter in ext4_block_bitmap_csum_set. After this,
group parameter in ext4_set_bitmap_checksums is also not us

ext4: remove unused group parameter in ext4_block_bitmap_csum_set

Remove unused group parameter in ext4_block_bitmap_csum_set. After this,
group parameter in ext4_set_bitmap_checksums is also not used, just
remove it too.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230221203027.2359920-5-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: remove unused group parameter in ext4_block_bitmap_csum_verify

Remove unused group parameter in ext4_block_bitmap_csum_verify.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-b

ext4: remove unused group parameter in ext4_block_bitmap_csum_verify

Remove unused group parameter in ext4_block_bitmap_csum_verify.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230221203027.2359920-4-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: remove unused group parameter in ext4_inode_bitmap_csum_set

Remove unused group parameter in ext4_inode_bitmap_csum_set.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan

ext4: remove unused group parameter in ext4_inode_bitmap_csum_set

Remove unused group parameter in ext4_inode_bitmap_csum_set.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230221203027.2359920-3-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: remove unused group parameter in ext4_inode_bitmap_csum_verify

Remove unused group parameter in ext4_inode_bitmap_csum_verify.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-b

ext4: remove unused group parameter in ext4_inode_bitmap_csum_verify

Remove unused group parameter in ext4_inode_bitmap_csum_verify.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230221203027.2359920-2-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: Fix comment about the 64BIT feature

64BIT is part of the incompatible feature set, update the comment
accordingly.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Darrick

ext4: Fix comment about the 64BIT feature

64BIT is part of the incompatible feature set, update the comment
accordingly.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20230301133842.671821-1-tudor.ambarus@linaro.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: fix incorrect options show of original mount_opt and extend mount_opt2

Current _ext4_show_options() do not distinguish MOPT_2 flag, so it mixed
extend sbi->s_mount_opt2 options with sbi->s_mou

ext4: fix incorrect options show of original mount_opt and extend mount_opt2

Current _ext4_show_options() do not distinguish MOPT_2 flag, so it mixed
extend sbi->s_mount_opt2 options with sbi->s_mount_opt, it could lead to
show incorrect options, e.g. show fc_debug_force if we mount with
errors=continue mode and miss it if we set.

$ mkfs.ext4 /dev/pmem0
$ mount -o errors=remount-ro /dev/pmem0 /mnt
$ cat /proc/fs/ext4/pmem0/options | grep fc_debug_force
#empty
$ mount -o remount,errors=continue /mnt
$ cat /proc/fs/ext4/pmem0/options | grep fc_debug_force
fc_debug_force
$ mount -o remount,errors=remount-ro,fc_debug_force /mnt
$ cat /proc/fs/ext4/pmem0/options | grep fc_debug_force
#empty

Fixes: 995a3ed67fc8 ("ext4: add fast_commit feature and handling for extended mount options")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230129034939.3702550-1-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

fs: port inode_init_owner() to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is ju

fs: port inode_init_owner() to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->fileattr_set() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is

fs: port ->fileattr_set() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just

fs: port ->setattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

show more ...

ext4: switch to using ext4_do_writepages() for ordered data writeout

Use the standard writepages method (ext4_do_writepages()) to perform
writeout of ordered data during journal commit.

Reviewed-by

ext4: switch to using ext4_do_writepages() for ordered data writeout

Use the standard writepages method (ext4_do_writepages()) to perform
writeout of ordered data during journal commit.

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221207112722.22220-8-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

show more ...

ext4: move keep_towrite handling to ext4_bio_write_page()

When we are writing back page but we cannot for some reason write all
its buffers (e.g. because we cannot allocate blocks in current context

ext4: move keep_towrite handling to ext4_bio_write_page()

When we are writing back page but we cannot for some reason write all
its buffers (e.g. because we cannot allocate blocks in current context) we
have to keep TOWRITE tag set in the mapping as otherwise racing
WB_SYNC_ALL writeback that could write these buffers can skip the page
and result in data loss. We will need this logic for writeback during
transaction commit so move the logic from ext4_writepage() to
ext4_bio_write_page().

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221207112722.22220-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: don't set up encryption key during jbd2 transaction

Commit a80f7fcf1867 ("ext4: fixup ext4_fc_track_* functions' signature")
extended the scope of the transaction in ext4_unlink() too far, mak

ext4: don't set up encryption key during jbd2 transaction

Commit a80f7fcf1867 ("ext4: fixup ext4_fc_track_* functions' signature")
extended the scope of the transaction in ext4_unlink() too far, making
it include the call to ext4_find_entry(). However, ext4_find_entry()
can deadlock when called from within a transaction because it may need
to set up the directory's encryption key.

Fix this by restoring the transaction to its original scope.

Reported-by: syzbot+1a748d0007eeac3ab079@syzkaller.appspotmail.com
Fixes: a80f7fcf1867 ("ext4: fixup ext4_fc_track_* functions' signature")
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221106224841.279231-3-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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ext4: fix undefined behavior in bit shift for ext4_check_flag_values

Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned. The UBSAN warning calltrace like b

ext4: fix undefined behavior in bit shift for ext4_check_flag_values

Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned. The UBSAN warning calltrace like below:

UBSAN: shift-out-of-bounds in fs/ext4/ext4.h:591:2
left shift of 1 by 31 places cannot be represented in type 'int'
Call Trace:
<TASK>
dump_stack_lvl+0x7d/0xa5
dump_stack+0x15/0x1b
ubsan_epilogue+0xe/0x4e
__ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
ext4_init_fs+0x5a/0x277
do_one_initcall+0x76/0x430
kernel_init_freeable+0x3b3/0x422
kernel_init+0x24/0x1e0
ret_from_fork+0x1f/0x30
</TASK>

Fixes: 9a4c80194713 ("ext4: ensure Inode flags consistency are checked at build time")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20221031055833.3966222-1-cuigaosheng1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

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ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode

There are many places that will get unhappy (and crash) when ext4_iget()
returns a bad inode. However, if iget the boot loader inode, all

ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode

There are many places that will get unhappy (and crash) when ext4_iget()
returns a bad inode. However, if iget the boot loader inode, allows a bad
inode to be returned, because the inode may not be initialized. This
mechanism can be used to bypass some checks and cause panic. To solve this
problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag
we'd be returning bad inode from ext4_iget(), otherwise we always return
the error code if the inode is bad inode.(suggested by Jan Kara)

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221026042310.3839669-4-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

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ext4: factor out ext4_free_ext_path()

Factor out ext4_free_ext_path() to free extent path. As after previous patch
'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static.

Signed-off-

ext4: factor out ext4_free_ext_path()

Factor out ext4_free_ext_path() to free extent path. As after previous patch
'ext4_ext_drop_refs()' is only used in 'extents.c', so make it static.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220924021211.3831551-3-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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