linux-stable.git/fs/ext4/inline.c, branch v5.4.201

ext4: fix bug_on in ext4_writepages

2022-06-14T16:11:45+00:00

commit ef09ed5d37b84d18562b30cf7253e57062d0db05 upstream.

we got issue as follows:
EXT4-fs error (device loop0): ext4_mb_generate_buddy:1141: group 0, block bitmap and bg descriptor inconsistent: 25 vs 31513 free cls
------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2708!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 2 PID: 2147 Comm: rep Not tainted 5.18.0-rc2-next-20220413+ #155
RIP: 0010:ext4_writepages+0x1977/0x1c10
RSP: 0018:ffff88811d3e7880 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000
RDX: 0000000000000000 RSI: ffff88811c098000 RDI: 0000000000000002
RBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000
R10: 0000000000000007 R11: ffffed10250281ea R12: 0000000000000001
R13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028
FS:  00007f443aed9740(0000) GS:ffff8883aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 
 do_writepages+0x130/0x3a0
 filemap_fdatawrite_wbc+0x83/0xa0
 filemap_flush+0xab/0xe0
 ext4_alloc_da_blocks+0x51/0x120
 __ext4_ioctl+0x1534/0x3210
 __x64_sys_ioctl+0x12c/0x170
 do_syscall_64+0x3b/0x90

It may happen as follows:
1. write inline_data inode
vfs_write
  new_sync_write
    ext4_file_write_iter
      ext4_buffered_write_iter
        generic_perform_write
          ext4_da_write_begin
            ext4_da_write_inline_data_begin -> If inline data size too
            small will allocate block to write, then mapping will has
            dirty page
                ext4_da_convert_inline_data_to_extent ->clear EXT4_STATE_MAY_INLINE_DATA
2. fallocate
do_vfs_ioctl
  ioctl_preallocate
    vfs_fallocate
      ext4_fallocate
        ext4_convert_inline_data
          ext4_convert_inline_data_nolock
            ext4_map_blocks -> fail will goto restore data
            ext4_restore_inline_data
              ext4_create_inline_data
              ext4_write_inline_data
              ext4_set_inode_state -> set inode EXT4_STATE_MAY_INLINE_DATA
3. writepages
__ext4_ioctl
  ext4_alloc_da_blocks
    filemap_flush
      filemap_fdatawrite_wbc
        do_writepages
          ext4_writepages
            if (ext4_has_inline_data(inode))
              BUG_ON(ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))

The root cause of this issue is we destory inline data until call
ext4_writepages under delay allocation mode.  But there maybe already
convert from inline to extent.  To solve this issue, we call
filemap_flush first..

Cc: stable@kernel.org
Signed-off-by: Ye Bin 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20220516122634.1690462-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: fix error handling in ext4_restore_inline_data()

2022-02-08T17:24:34+00:00

commit 897026aaa73eb2517dfea8d147f20ddb0b813044 upstream.

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.


[73131.453234] kernel BUG at fs/ext4/inline.c:223!


 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 
Signed-off-by: Ritesh Harjani 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/9f4cd7dfd54fa58ff27270881823d94ddf78dd07.1642416995.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman



ext4: correct the error path of ext4_write_inline_data_end()
2021-10-17T08:42:33+00:00

[ Upstream commit 55ce2f649b9e88111270333a8127e23f4f8f42d7 ]

Current error path of ext4_write_inline_data_end() is not correct.

Firstly, it should pass out the error value if ext4_get_inode_loc()
return fail, or else it could trigger infinite loop if we inject error
here. And then it's better to add inode to orphan list if it return fail
in ext4_journal_stop(), otherwise we could not restore inline xattr
entry after power failure. Finally, we need to reset the 'ret' value if
ext4_write_inline_data_end() return success in ext4_write_end() and
ext4_journalled_write_end(), otherwise we could not get the error return
value of ext4_journal_stop().

Signed-off-by: Zhang Yi 
Reviewed-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Link: https://lore.kernel.org/r/20210716122024.1105856-3-yi.zhang@huawei.com
Signed-off-by: Sasha Levin 




ext4: fix race writing to an inline_data file while its xattrs are changing
2021-09-12T06:56:38+00:00

commit a54c4613dac1500b40e4ab55199f7c51f028e848 upstream.

The location of the system.data extended attribute can change whenever
xattr_sem is not taken.  So we need to recalculate the i_inline_off
field since it mgiht have changed between ext4_write_begin() and
ext4_write_end().

This means that caching i_inline_off is probably not helpful, so in
the long run we should probably get rid of it and shrink the in-memory
ext4 inode slightly, but let's fix the race the simple way for now.

Cc: stable@kernel.org
Fixes: f19d5870cbf72 ("ext4: add normal write support for inline data")
Reported-by: syzbot+13146364637c7363a7de@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman 




ext4: unlock xattr_sem properly in ext4_inline_data_truncate()
2020-11-18T18:20:28+00:00

commit 7067b2619017d51e71686ca9756b454de0e5826a upstream.

It takes xattr_sem to check inline data again but without unlock it
in case not have. So unlock it before return.

Fixes: aef1c8513c1f ("ext4: let ext4_truncate handle inline data correctly")
Reported-by: Dan Carpenter 
Cc: Tao Ma 
Signed-off-by: Joseph Qi 
Reviewed-by: Andreas Dilger 
Link: https://lore.kernel.org/r/1604370542-124630-1-git-send-email-joseph.qi@linux.alibaba.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman 





ext4: set error return correctly when ext4_htree_store_dirent fails
2019-08-12T18:29:38+00:00

Currently when the call to ext4_htree_store_dirent fails the error return
variable 'ret' is is not being set to the error code and variable count is
instead, hence the error code is not being returned.  Fix this by assigning
ret to the error return code.

Addresses-Coverity: ("Unused value")
Fixes: 8af0f0822797 ("ext4: fix readdir error in the case of inline_data+dir_index")
Signed-off-by: Colin Ian King 
Signed-off-by: Theodore Ts'o 




ext4: rename htree_inline_dir_to_tree() to ext4_inlinedir_to_tree()
2019-06-22T01:57:00+00:00

Clean up namespace pollution by the inline_data code.

Signed-off-by: Theodore Ts'o 




ext4: refactor initialize_dirent_tail()
2019-06-21T20:31:47+00:00

Move the calculation of the location of the dirent tail into
initialize_dirent_tail().  Also prefix the function with ext4_ to fix
kernel namepsace polution.

Signed-off-by: Theodore Ts'o 





ext4: rename "dirent_csum" functions to use "dirblock"
2019-06-21T19:49:26+00:00

Functions such as ext4_dirent_csum_verify() and ext4_dirent_csum_set()
don't actually operate on a directory entry, but a directory block.
And while they take a struct ext4_dir_entry *dirent as an argument, it
had better be the first directory at the beginning of the direct
block, or things will go very wrong.

Rename the following functions so that things make more sense, and
remove a lot of confusing casts along the way:

   ext4_dirent_csum_verify	 -> ext4_dirblock_csum_verify
   ext4_dirent_csum_set		 -> ext4_dirblock_csum_set
   ext4_dirent_csum		 -> ext4_dirblock_csum
   ext4_handle_dirty_dirent_node -> ext4_handle_dirty_dirblock

Signed-off-by: Theodore Ts'o 




ext4: Support case-insensitive file name lookups
2019-04-25T18:12:08+00:00

This patch implements the actual support for case-insensitive file name
lookups in ext4, based on the feature bit and the encoding stored in the
superblock.

A filesystem that has the casefold feature set is able to configure
directories with the +F (EXT4_CASEFOLD_FL) attribute, enabling lookups
to succeed in that directory in a case-insensitive fashion, i.e: match
a directory entry even if the name used by userspace is not a byte per
byte match with the disk name, but is an equivalent case-insensitive
version of the Unicode string.  This operation is called a
case-insensitive file name lookup.

The feature is configured as an inode attribute applied to directories
and inherited by its children.  This attribute can only be enabled on
empty directories for filesystems that support the encoding feature,
thus preventing collision of file names that only differ by case.

* dcache handling:

For a +F directory, Ext4 only stores the first equivalent name dentry
used in the dcache. This is done to prevent unintentional duplication of
dentries in the dcache, while also allowing the VFS code to quickly find
the right entry in the cache despite which equivalent string was used in
a previous lookup, without having to resort to ->lookup().

d_hash() of casefolded directories is implemented as the hash of the
casefolded string, such that we always have a well-known bucket for all
the equivalencies of the same string. d_compare() uses the
utf8_strncasecmp() infrastructure, which handles the comparison of
equivalent, same case, names as well.

For now, negative lookups are not inserted in the dcache, since they
would need to be invalidated anyway, because we can't trust missing file
dentries.  This is bad for performance but requires some leveraging of
the vfs layer to fix.  We can live without that for now, and so does
everyone else.

* on-disk data:

Despite using a specific version of the name as the internal
representation within the dcache, the name stored and fetched from the
disk is a byte-per-byte match with what the user requested, making this
implementation 'name-preserving'. i.e. no actual information is lost
when writing to storage.

DX is supported by modifying the hashes used in +F directories to make
them case/encoding-aware.  The new disk hashes are calculated as the
hash of the full casefolded string, instead of the string directly.
This allows us to efficiently search for file names in the htree without
requiring the user to provide an exact name.

* Dealing with invalid sequences:

By default, when a invalid UTF-8 sequence is identified, ext4 will treat
it as an opaque byte sequence, ignoring the encoding and reverting to
the old behavior for that unique file.  This means that case-insensitive
file name lookup will not work only for that file.  An optional bit can
be set in the superblock telling the filesystem code and userspace tools
to enforce the encoding.  When that optional bit is set, any attempt to
create a file name using an invalid UTF-8 sequence will fail and return
an error to userspace.

* Normalization algorithm:

The UTF-8 algorithms used to compare strings in ext4 is implemented
lives in fs/unicode, and is based on a previous version developed by
SGI.  It implements the Canonical decomposition (NFD) algorithm
described by the Unicode specification 12.1, or higher, combined with
the elimination of ignorable code points (NFDi) and full
case-folding (CF) as documented in fs/unicode/utf8_norm.c.

NFD seems to be the best normalization method for EXT4 because:

  - It has a lower cost than NFC/NFKC (which requires
    decomposing to NFD as an intermediary step)
  - It doesn't eliminate important semantic meaning like
    compatibility decompositions.

Although:

  - This implementation is not completely linguistic accurate, because
  different languages have conflicting rules, which would require the
  specialization of the filesystem to a given locale, which brings all
  sorts of problems for removable media and for users who use more than
  one language.

Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Theodore Ts'o