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Filename Latest commit message Latest commit date
Baokun Li ee2fd44860 ext4: only update i_reserved_data_blocks on successful block allocation
commit de25d6e9610a8b30cce9bbb19b50615d02ebca02 upstream.

In our fault injection test, we create an ext4 file, migrate it to
non-extent based file, then punch a hole and finally trigger a WARN_ON
in the ext4_da_update_reserve_space():

EXT4-fs warning (device sda): ext4_da_update_reserve_space:369:
ino 14, used 11 with only 10 reserved data blocks

When writing back a non-extent based file, if we enable delalloc, the
number of reserved blocks will be subtracted from the number of blocks
mapped by ext4_ind_map_blocks(), and the extent status tree will be
updated. We update the extent status tree by first removing the old
extent_status and then inserting the new extent_status. If the block range
we remove happens to be in an extent, then we need to allocate another
extent_status with ext4_es_alloc_extent().

       use old    to remove   to add new
    |----------|------------|------------|
              old extent_status

The problem is that the allocation of a new extent_status failed due to a
fault injection, and __es_shrink() did not get free memory, resulting in
a return of -ENOMEM. Then do_writepages() retries after receiving -ENOMEM,
we map to the same extent again, and the number of reserved blocks is again
subtracted from the number of blocks in that extent. Since the blocks in
the same extent are subtracted twice, we end up triggering WARN_ON at
ext4_da_update_reserve_space() because used > ei->i_reserved_data_blocks.

For non-extent based file, we update the number of reserved blocks after
ext4_ind_map_blocks() is executed, which causes a problem that when we call
ext4_ind_map_blocks() to create a block, it doesn't always create a block,
but we always reduce the number of reserved blocks. So we move the logic
for updating reserved blocks to ext4_ind_map_blocks() to ensure that the
number of reserved blocks is updated only after we do succeed in allocating
some new blocks.

Fixes: 5f634d064c ("ext4: Fix quota accounting error with fallocate")
Cc: stable@kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230424033846.4732-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27 08:37:35 +02:00
arch powerpc: Fail build if using recordmcount with binutils v2.37 2023-07-27 08:37:34 +02:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs
crypto
Documentation fs: Lock moved directories 2023-07-27 08:37:26 +02:00
drivers misc: fastrpc: Create fastrpc scalar with correct buffer count 2023-07-27 08:37:34 +02:00
fs ext4: only update i_reserved_data_blocks on successful block allocation 2023-07-27 08:37:35 +02:00
include net/sched: make psched_mtu() RTNL-less safe 2023-07-27 08:37:33 +02:00
init
ipc
kernel workqueue: clean up WORK_* constant types, clarify masking 2023-07-27 08:37:29 +02:00
lib lib/ts_bm: reset initial match offset for every block of text 2023-07-27 08:37:12 +02:00
LICENSES
mm
net SUNRPC: Fix UAF in svc_tcp_listen_data_ready() 2023-07-27 08:37:35 +02:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts modpost: fix off by one in is_executable_section() 2023-07-27 08:37:18 +02:00
security integrity: Fix possible multiple allocation in integrity_inode_get() 2023-07-27 08:37:25 +02:00
sound ALSA: jack: Fix mutex call in snd_jack_report() 2023-07-27 08:37:24 +02:00
tools perf dwarf-aux: Fix off-by-one in die_get_varname() 2023-07-27 08:37:17 +02:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
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COPYING
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Kconfig
MAINTAINERS
Makefile Linux 5.4.250 2023-07-24 19:10:53 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.