Commit Graph

192 Commits

Author SHA1 Message Date
Harshad Shirwadkar
8016e29f43 ext4: fast commit recovery path
This patch adds fast commit recovery path support for Ext4 file
system. We add several helper functions that are similar in spirit to
e2fsprogs journal recovery path handlers. Example of such functions
include - a simple block allocator, idempotent block bitmap update
function etc. Using these routines and the fast commit log in the fast
commit area, the recovery path (ext4_fc_replay()) performs fast commit
log recovery.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-8-harshadshirwadkar@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-21 23:22:38 -04:00
zhangyi (F)
2d069c0889 ext4: use common helpers in all places reading metadata buffers
Revome all open codes that read metadata buffers, switch to use
ext4_read_bh_*() common helpers.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-4-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-18 10:37:14 -04:00
zhangyi (F)
d9befedaaf ext4: clear buffer verified flag if read meta block from disk
The metadata buffer is no longer trusted after we read it from disk
again because it is not uptodate for some reasons (e.g. failed to write
back). Otherwise we may get below memory corruption problem in
ext4_ext_split()->memset() if we read stale data from the newly
allocated extent block on disk which has been failed to async write
out but miss verify again since the verified bit has already been set
on the buffer.

[   29.774674] BUG: unable to handle kernel paging request at ffff88841949d000
...
[   29.783317] Oops: 0002 [#2] SMP
[   29.784219] R10: 00000000000f4240 R11: 0000000000002e28 R12: ffff88842fa1c800
[   29.784627] CPU: 1 PID: 126 Comm: kworker/u4:3 Tainted: G      D W
[   29.785546] R13: ffffffff9cddcc20 R14: ffffffff9cddd420 R15: ffff88842fa1c2f8
[   29.786679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS ?-20190727_0738364
[   29.787588] FS:  0000000000000000(0000) GS:ffff88842fa00000(0000) knlGS:0000000000000000
[   29.789288] Workqueue: writeback wb_workfn
[   29.790319] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.790321]  (flush-8:0)
[   29.790844] CR2: 0000000000000008 CR3: 00000004234f2000 CR4: 00000000000006f0
[   29.791924] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   29.792839] RIP: 0010:__memset+0x24/0x30
[   29.793739] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   29.794256] Code: 90 90 90 90 90 90 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 033
[   29.795161] Kernel panic - not syncing: Fatal exception in interrupt
...
[   29.808149] Call Trace:
[   29.808475]  ext4_ext_insert_extent+0x102e/0x1be0
[   29.809085]  ext4_ext_map_blocks+0xa89/0x1bb0
[   29.809652]  ext4_map_blocks+0x290/0x8a0
[   29.809085]  ext4_ext_map_blocks+0xa89/0x1bb0
[   29.809652]  ext4_map_blocks+0x290/0x8a0
[   29.810161]  ext4_writepages+0xc85/0x17c0
...

Fix this by clearing buffer's verified bit if we read meta block from
disk again.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200924073337.861472-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-10-18 10:37:13 -04:00
Theodore Ts'o
ab74c7b23f ext4: indicate via a block bitmap read is prefetched via a tracepoint
Modify the ext4_read_block_bitmap_load tracepoint so that it tells us
whether a block bitmap is being prefetched.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Artem Blagodarenko <artem.blagodarenko@gmail.com>
2020-08-07 14:12:35 -04:00
Alex Zhuravlev
cfd7323772 ext4: add prefetching for block allocation bitmaps
This should significantly improve bitmap loading, especially for flex
groups as it tries to load all bitmaps within a flex.group instead of
one by one synchronously.

Prefetching is done in 8 * flex_bg groups, so it should be 8
read-ahead reads for a single allocating thread. At the end of
allocation the thread waits for read-ahead completion and initializes
buddy information so that read-aheads are not lost in case of memory
pressure.

At cr=0 the number of prefetching IOs is limited per allocation
context to prevent a situation when mballoc loads thousands of bitmaps
looking for a perfect group and ignoring groups with good chunks.

Together with the patch "ext4: limit scanning of uninitialized groups"
the mount time (which includes few tiny allocations) of a 1PB
filesystem is reduced significantly:

               0% full    50%-full unpatched    patched
  mount time       33s                9279s       563s

[ Restructured by tytso; removed the state flags in the allocation
  context, so it can be used to lazily prefetch the allocation bitmaps
  immediately after the file system is mounted.  Skip prefetching
  block groups which are uninitialized.  Finally pass in the
  REQ_RAHEAD flag to the block layer while prefetching. ]

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-08-06 01:44:48 -04:00
Ritesh Harjani
9bee5779ee ext4: balloc: use task_pid_nr() helper
Use task_pid_nr() function instead of current->pid.
There should be no functionality change in this patch.

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/4b58403e15e9c8deb34a1b93deb3fc9cd153ab84.1589086800.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-06-03 23:16:52 -04:00
Josh Triplett
9033783c8c ext4: fix return-value types in several function comments
The documentation comments for ext4_read_block_bitmap_nowait and
ext4_read_inode_bitmap describe them as returning NULL on error, but
they return an ERR_PTR on error; update the documentation to match.

The documentation comment for ext4_wait_block_bitmap describes it as
returning 1 on error, but it returns -errno on error; update the
documentation to match.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Ritesh Harani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/60a3f4996f4932c45515aaa6b75ca42f2a78ec9b.1585512514.git.josh@joshtriplett.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-04-15 23:58:48 -04:00
Theodore Ts'o
54d3adbc29 ext4: save all error info in save_error_info() and drop ext4_set_errno()
Using a separate function, ext4_set_errno() to set the errno is
problematic because it doesn't do the right thing once
s_last_error_errorcode is non-zero.  It's also less racy to set all of
the error information all at once.  (Also, as a bonus, it shrinks code
size slightly.)

Link: https://lore.kernel.org/r/20200329020404.686965-1-tytso@mit.edu
Fixes: 878520ac45 ("ext4: save the error code which triggered...")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-04-01 17:29:06 -04:00
Theodore Ts'o
1d0c3924a9 ext4: fix potential race between online resizing and write operations
During an online resize an array of pointers to buffer heads gets
replaced so it can get enlarged.  If there is a racing block
allocation or deallocation which uses the old array, and the old array
has gotten reused this can lead to a GPF or some other random kernel
memory getting modified.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206443
Link: https://lore.kernel.org/r/20200221053458.730016-2-tytso@mit.edu
Reported-by: Suraj Jitindar Singh <surajjs@amazon.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2020-02-21 00:37:09 -05:00
Theodore Ts'o
46f870d690 ext4: simulate various I/O and checksum errors when reading metadata
This allows us to test various error handling code paths

Link: https://lore.kernel.org/r/20191209012317.59398-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-26 11:28:31 -05:00
Theodore Ts'o
878520ac45 ext4: save the error code which triggered an ext4_error() in the superblock
This allows the cause of an ext4_error() report to be categorized
based on whether it was triggered due to an I/O error, or an memory
allocation error, or other possible causes.  Most errors are caused by
a detected file system inconsistency, so the default code stored in
the superblock will be EXT4_ERR_EFSCORRUPTED.

Link: https://lore.kernel.org/r/20191204032335.7683-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-26 11:28:23 -05:00
Theodore Ts'o
c60990b361 ext4: clean up kerneldoc warnigns when building with W=1
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-06-19 16:30:03 -04:00
Wang Shilong
5ef2a69993 ext4: use ext4_warning() for sb_getblk failure
Out of memory should not be considered as critical errors; so replace
ext4_error() with ext4_warnig().

Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2018-08-01 12:02:31 -04:00
Theodore Ts'o
8d5a803c6a ext4: check for allocation block validity with block group locked
With commit 044e6e3d74: "ext4: don't update checksum of new
initialized bitmaps" the buffer valid bit will get set without
actually setting up the checksum for the allocation bitmap, since the
checksum will get calculated once we actually allocate an inode or
block.

If we are doing this, then we need to (re-)check the verified bit
after we take the block group lock.  Otherwise, we could race with
another process reading and verifying the bitmap, which would then
complain about the checksum being invalid.

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780137

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2018-07-12 19:08:05 -04:00
Theodore Ts'o
8844618d8a ext4: only look at the bg_flags field if it is valid
The bg_flags field in the block group descripts is only valid if the
uninit_bg or metadata_csum feature is enabled.  We were not
consistently looking at this field; fix this.

Also block group #0 must never have uninitialized allocation bitmaps,
or need to be zeroed, since that's where the root inode, and other
special inodes are set up.  Check for these conditions and mark the
file system as corrupted if they are detected.

This addresses CVE-2018-10876.

https://bugzilla.kernel.org/show_bug.cgi?id=199403

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2018-06-14 00:58:00 -04:00
Theodore Ts'o
819b23f1c5 ext4: always check block group bounds in ext4_init_block_bitmap()
Regardless of whether the flex_bg feature is set, we should always
check to make sure the bits we are setting in the block bitmap are
within the block group bounds.

https://bugzilla.kernel.org/show_bug.cgi?id=199865

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2018-06-13 23:00:48 -04:00
Wang Shilong
736dedbb1a ext4: mark block bitmap corrupted when found
There are still some cases that we missed to set
block bitmaps corrupted bit properly:

1) block bitmap number is wrong.
2) failed to read block bitmap due to disk errors.
3) double free block bitmaps..
4) some mismatch check with bitmaps vs buddy information.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
2018-05-12 12:37:58 -04:00
Wang Shilong
db79e6d1fb ext4: add new ext4_mark_group_bitmap_corrupted() helper
Since there are many places to set inode/block bitmap
corrupt bit, add a new helper for it, which will make
codes more clear.

Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
2018-05-12 11:39:40 -04:00
Lukas Czerner
22be37acce ext4: fix bitmap position validation
Currently in ext4_valid_block_bitmap() we expect the bitmap to be
positioned anywhere between 0 and s_blocksize clusters, but that's
wrong because the bitmap can be placed anywhere in the block group. This
causes false positives when validating bitmaps on perfectly valid file
system layouts. Fix it by checking whether the bitmap is within the group
boundary.

The problem can be reproduced using the following

mkfs -t ext3 -E stride=256 /dev/vdb1
mount /dev/vdb1 /mnt/test
cd /mnt/test
wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.16.3.tar.xz
tar xf linux-4.16.3.tar.xz

This will result in the warnings in the logs

EXT4-fs error (device vdb1): ext4_validate_block_bitmap:399: comm tar: bg 84: block 2774529: invalid block bitmap

[ Changed slightly for clarity and to not drop a overflow test -- TYT ]

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Ilya Dryomov <idryomov@gmail.com>
Fixes: 7dac4a1726 ("ext4: add validity checks for bitmap block numbers")
Cc: stable@vger.kernel.org
2018-04-24 11:31:44 -04:00
Theodore Ts'o
7dac4a1726 ext4: add validity checks for bitmap block numbers
An privileged attacker can cause a crash by mounting a crafted ext4
image which triggers a out-of-bounds read in the function
ext4_valid_block_bitmap() in fs/ext4/balloc.c.

This issue has been assigned CVE-2018-1093.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199181
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1560782
Reported-by: Wen Xu <wen.xu@gatech.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2018-03-26 23:54:10 -04:00
Theodore Ts'o
044e6e3d74 ext4: don't update checksum of new initialized bitmaps
When reading the inode or block allocation bitmap, if the bitmap needs
to be initialized, do not update the checksum in the block group
descriptor.  That's because we're not set up to journal those changes.
Instead, just set the verified bit on the bitmap block, so that it's
not necessary to validate the checksum.

When a block or inode allocation actually happens, at that point the
checksum will be calculated, and update of the bg descriptor block
will be properly journalled.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2018-02-19 14:16:47 -05:00
Jun Piao
49598e04b5 ext4: use 'sbi' instead of 'EXT4_SB(sb)'
We could use 'sbi' instead of 'EXT4_SB(sb)' to make code more elegant.

Signed-off-by: Jun Piao <piaojun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2018-01-11 13:17:49 -05:00
Linus Torvalds
ae9a8c4bdc Add support for online resizing of file systems with bigalloc. Fix a
two data corruption bugs involving DAX, as well as a corruption bug
 after a crash during a racing fallocate and delayed allocation.
 Finally, a number of cleanups and optimizations.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:

 - Add support for online resizing of file systems with bigalloc

 - Fix a two data corruption bugs involving DAX, as well as a corruption
   bug after a crash during a racing fallocate and delayed allocation.

 - Finally, a number of cleanups and optimizations.

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: improve smp scalability for inode generation
  ext4: add support for online resizing with bigalloc
  ext4: mention noload when recovering on read-only device
  Documentation: fix little inconsistencies
  ext4: convert timers to use timer_setup()
  jbd2: convert timers to use timer_setup()
  ext4: remove duplicate extended attributes defs
  ext4: add ext4_should_use_dax()
  ext4: add sanity check for encryption + DAX
  ext4: prevent data corruption with journaling + DAX
  ext4: prevent data corruption with inline data + DAX
  ext4: fix interaction between i_size, fallocate, and delalloc after a crash
  ext4: retry allocations conservatively
  ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA
  ext4: Add iomap support for inline data
  iomap: Add IOMAP_F_DATA_INLINE flag
  iomap: Switch from blkno to disk offset
2017-11-14 12:59:42 -08:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Theodore Ts'o
68fd97504a ext4: retry allocations conservatively
Now that we no longer try to reserve metadata blocks for delayed
allocations (which tended to overestimate the required number of
blocks significantly), we really don't need retry allocations when the
disk is very full as aggressively any more.

The only time when it makes sense to retry an allocation is if we have
freshly deleted blocks that will only become available after a
transaction commit.  And if we lose that race, it's not worth it to
try more than once.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-10-01 17:59:54 -04:00
Linus Torvalds
396d10993f The major change this cycle is deleting ext4's copy of the file system
encryption code and switching things over to using the copies in
 fs/crypto.  I've updated the MAINTAINERS file to add an entry for
 fs/crypto listing Jaeguk Kim and myself as the maintainers.
 
 There are also a number of bug fixes, most notably for some problems
 found by American Fuzzy Lop (AFL) courtesy of Vegard Nossum.  Also
 fixed is a writeback deadlock detected by generic/130, and some
 potential races in the metadata checksum code.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "The major change this cycle is deleting ext4's copy of the file system
  encryption code and switching things over to using the copies in
  fs/crypto.  I've updated the MAINTAINERS file to add an entry for
  fs/crypto listing Jaeguk Kim and myself as the maintainers.

  There are also a number of bug fixes, most notably for some problems
  found by American Fuzzy Lop (AFL) courtesy of Vegard Nossum.  Also
  fixed is a writeback deadlock detected by generic/130, and some
  potential races in the metadata checksum code"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
  ext4: verify extent header depth
  ext4: short-cut orphan cleanup on error
  ext4: fix reference counting bug on block allocation error
  MAINTAINRES: fs-crypto maintainers update
  ext4 crypto: migrate into vfs's crypto engine
  ext2: fix filesystem deadlock while reading corrupted xattr block
  ext4: fix project quota accounting without quota limits enabled
  ext4: validate s_reserved_gdt_blocks on mount
  ext4: remove unused page_idx
  ext4: don't call ext4_should_journal_data() on the journal inode
  ext4: Fix WARN_ON_ONCE in ext4_commit_super()
  ext4: fix deadlock during page writeback
  ext4: correct error value of function verifying dx checksum
  ext4: avoid modifying checksum fields directly during checksum verification
  ext4: check for extents that wrap around
  jbd2: make journal y2038 safe
  jbd2: track more dependencies on transaction commit
  jbd2: move lockdep tracking to journal_s
  jbd2: move lockdep instrumentation for jbd2 handles
  ext4: respect the nobarrier mount option in nojournal mode
  ...
2016-07-26 18:35:55 -07:00
Theodore Ts'o
5b9554dc5b ext4: validate s_reserved_gdt_blocks on mount
If s_reserved_gdt_blocks is extremely large, it's possible for
ext4_init_block_bitmap(), which is called when ext4 sets up an
uninitialized block bitmap, to corrupt random kernel memory.  Add the
same checks which e2fsck has --- it must never be larger than
blocksize / sizeof(__u32) --- and then add a backup check in
ext4_init_block_bitmap() in case the superblock gets modified after
the file system is mounted.

Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2016-07-05 20:01:52 -04:00
Theodore Ts'o
d08854f5bc ext4: optimize ext4_should_retry_alloc() to improve ENOSPC performance
If there are no pending blocks to be released after a commit, forcing
a journal commit has no hope of helping.  It's possible that a commit
had just completed, so if there are now free blocks available for
allocation, it's worth retrying the commit.

Reported-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-06-26 18:24:01 -04:00
Mike Christie
2a222ca992 fs: have submit_bh users pass in op and flags separately
This has submit_bh users pass in the operation and flags separately,
so submit_bh_wbc can setup the bio op and bi_rw flags on the bio that
is submitted.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Jan Kara
dbc427ce40 ext4: fix race in transient ENOSPC detection
When there are blocks to free in the running transaction, block
allocator can return ENOSPC although the filesystem has some blocks to
free. We use ext4_should_retry_alloc() to force commit of the current
transaction and return whether anything was committed so that it makes
sense to retry the allocation. However the transaction may get committed
after block allocation fails but before we call
ext4_should_retry_alloc(). So ext4_should_retry_alloc() returns false
because there is nothing to commit and we wrongly return ENOSPC.

Fix the race by unconditionally returning 1 from ext4_should_retry_alloc()
when we tried to commit a transaction. This should not add any
unnecessary retries since we had a transaction running a while ago when
trying to allocate blocks and we want to retry the allocation once that
transaction has committed anyway.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-05-13 00:42:40 -04:00
Jan Kara
05145bd799 ext4: fix scheduling in atomic on group checksum failure
When block group checksum is wrong, we call ext4_error() while holding
group spinlock from ext4_init_block_bitmap() or
ext4_init_inode_bitmap() which results in scheduling while in atomic.
Fix the issue by calling ext4_error() later after dropping the spinlock.

CC: stable@vger.kernel.org
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-02-11 23:15:12 -05:00
Darrick J. Wong
9008a58e5d ext4: make the bitmap read routines return real error codes
Make the bitmap reaading routines return real error codes (EIO,
EFSCORRUPTED, EFSBADCRC) which can then be reflected back to
userspace for more precise diagnosis work.

In particular, this means that mballoc no longer claims that we're out
of memory if the block bitmaps become corrupt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-17 21:33:24 -04:00
Darrick J. Wong
e2b911c535 ext4: clean up feature test macros with predicate functions
Create separate predicate functions to test/set/clear feature flags,
thereby replacing the wordy old macros.  Furthermore, clean out the
places where we open-coded feature tests.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2015-10-17 16:18:43 -04:00
Darrick J. Wong
6a797d2737 ext4: call out CRC and corruption errors with specific error codes
Instead of overloading EIO for CRC errors and corrupt structures,
return the same error codes that XFS returns for the same issues.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-17 16:16:04 -04:00
Lukas Czerner
41e5b7ed3e ext4: verify block bitmap even after fresh initialization
If we want to rely on the buffer_verified() flag of the block bitmap
buffer, we have to set it consistently. However currently if we're
initializing uninitialized block bitmap in
ext4_read_block_bitmap_nowait() we're not going to set buffer verified
at all.

We can do this by simply setting the flag on the buffer, but I think
it's actually better to run ext4_validate_block_bitmap() to make sure
that what we did in the ext4_init_block_bitmap() is right.

So run ext4_validate_block_bitmap() even after the block bitmap
initialization. Also bail out early from ext4_validate_block_bitmap() if
we see corrupt bitmap, since we already know it's corrupt and we do not
need to verify that.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-08 11:18:52 -04:00
Maurizio Lombardi
5a4f3145aa ext4: remove unnecessary lock/unlock of i_block_reservation_lock
This is a leftover of commit 71d4f7d032

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
2015-04-03 00:02:53 -04:00
Sheng Yong
72b8e0f9fa ext4: remove unused header files
Remove unused header files and header files which are included in
ext4.h.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-02 23:47:42 -04:00
Dmitry Monakhov
aef4885ae1 ext4: move error report out of atomic context in ext4_init_block_bitmap()
Error report likely result in IO so it is bad idea to do it from
atomic context.

This patch should fix following issue:

BUG: sleeping function called from invalid context at include/linux/buffer_head.h:349
in_atomic(): 1, irqs_disabled(): 0, pid: 137, name: kworker/u128:1
5 locks held by kworker/u128:1/137:
 #0:  ("writeback"){......}, at: [<ffffffff81085618>] process_one_work+0x228/0x4d0
 #1:  ((&(&wb->dwork)->work)){......}, at: [<ffffffff81085618>] process_one_work+0x228/0x4d0
 #2:  (jbd2_handle){......}, at: [<ffffffff81242622>] start_this_handle+0x712/0x7b0
 #3:  (&ei->i_data_sem){......}, at: [<ffffffff811fa387>] ext4_map_blocks+0x297/0x430
 #4:  (&(&bgl->locks[i].lock)->rlock){......}, at: [<ffffffff811f3180>] ext4_read_block_bitmap_nowait+0x5d0/0x630
CPU: 3 PID: 137 Comm: kworker/u128:1 Not tainted 3.17.0-rc2-00184-g82752e4 #165
Hardware name: Intel Corporation W2600CR/W2600CR, BIOS SE5C600.86B.99.99.x028.061320111235 06/13/2011
Workqueue: writeback bdi_writeback_workfn (flush-1:0)
 0000000000000411 ffff880813777288 ffffffff815c7fdc ffff880813777288
 ffff880813a8bba0 ffff8808137772a8 ffffffff8108fb30 ffff880803e01e38
 ffff880803e01e38 ffff8808137772c8 ffffffff811a8d53 ffff88080ecc6000
Call Trace:
 [<ffffffff815c7fdc>] dump_stack+0x51/0x6d
 [<ffffffff8108fb30>] __might_sleep+0xf0/0x100
 [<ffffffff811a8d53>] __sync_dirty_buffer+0x43/0xe0
 [<ffffffff811a8e03>] sync_dirty_buffer+0x13/0x20
 [<ffffffff8120f581>] ext4_commit_super+0x1d1/0x230
 [<ffffffff8120fa03>] save_error_info+0x23/0x30
 [<ffffffff8120fd06>] __ext4_error+0xb6/0xd0
 [<ffffffff8120f260>] ? ext4_group_desc_csum+0x140/0x190
 [<ffffffff811f2d8c>] ext4_read_block_bitmap_nowait+0x1dc/0x630
 [<ffffffff8122e23a>] ext4_mb_init_cache+0x21a/0x8f0
 [<ffffffff8113ae95>] ? lru_cache_add+0x55/0x60
 [<ffffffff8112e16c>] ? add_to_page_cache_lru+0x6c/0x80
 [<ffffffff8122eaa0>] ext4_mb_init_group+0x190/0x280
 [<ffffffff8122ec51>] ext4_mb_good_group+0xc1/0x190
 [<ffffffff8123309a>] ext4_mb_regular_allocator+0x17a/0x410
 [<ffffffff8122c821>] ? ext4_mb_use_preallocated+0x31/0x380
 [<ffffffff81233535>] ? ext4_mb_new_blocks+0x205/0x8e0
 [<ffffffff8116ed5c>] ? kmem_cache_alloc+0xfc/0x180
 [<ffffffff812335b0>] ext4_mb_new_blocks+0x280/0x8e0
 [<ffffffff8116f2c4>] ? __kmalloc+0x144/0x1c0
 [<ffffffff81221797>] ? ext4_find_extent+0x97/0x320
 [<ffffffff812257f4>] ext4_ext_map_blocks+0xbc4/0x1050
 [<ffffffff811fa387>] ? ext4_map_blocks+0x297/0x430
 [<ffffffff811fa3ab>] ext4_map_blocks+0x2bb/0x430
 [<ffffffff81200e43>] ? ext4_init_io_end+0x23/0x50
 [<ffffffff811feb44>] ext4_writepages+0x564/0xaf0
 [<ffffffff815cde3b>] ? _raw_spin_unlock+0x2b/0x40
 [<ffffffff810ac7bd>] ? lock_release_non_nested+0x2fd/0x3c0
 [<ffffffff811a009e>] ? writeback_sb_inodes+0x10e/0x490
 [<ffffffff811a009e>] ? writeback_sb_inodes+0x10e/0x490
 [<ffffffff811377e3>] do_writepages+0x23/0x40
 [<ffffffff8119c8ce>] __writeback_single_inode+0x9e/0x280
 [<ffffffff811a026b>] writeback_sb_inodes+0x2db/0x490
 [<ffffffff811a0664>] wb_writeback+0x174/0x2d0
 [<ffffffff810ac359>] ? lock_release_holdtime+0x29/0x190
 [<ffffffff811a0863>] wb_do_writeback+0xa3/0x200
 [<ffffffff811a0a40>] bdi_writeback_workfn+0x80/0x230
 [<ffffffff81085618>] ? process_one_work+0x228/0x4d0
 [<ffffffff810856cd>] process_one_work+0x2dd/0x4d0
 [<ffffffff81085618>] ? process_one_work+0x228/0x4d0
 [<ffffffff81085c1d>] worker_thread+0x35d/0x460
 [<ffffffff810858c0>] ? process_one_work+0x4d0/0x4d0
 [<ffffffff810858c0>] ? process_one_work+0x4d0/0x4d0
 [<ffffffff8108a885>] kthread+0xf5/0x100
 [<ffffffff810990e5>] ? local_clock+0x25/0x30
 [<ffffffff8108a790>] ? __init_kthread_worker+0x70/0x70
 [<ffffffff815ce2ac>] ret_from_fork+0x7c/0xb0
 [<ffffffff8108a790>] ? __init_kthread_work

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2014-10-13 03:42:12 -04:00
Theodore Ts'o
e3cf5d5d9a ext4: prepare to drop EXT4_STATE_DELALLOC_RESERVED
The EXT4_STATE_DELALLOC_RESERVED flag was originally implemented
because it was too hard to make sure the mballoc and get_block flags
could be reliably passed down through all of the codepaths that end up
calling ext4_mb_new_blocks().

Since then, we have mb_flags passed down through most of the code
paths, so getting rid of EXT4_STATE_DELALLOC_RESERVED isn't as tricky
as it used to.

This commit plumbs in the last of what is required, and then adds a
WARN_ON check to make sure we haven't missed anything.  If this passes
a full regression test run, we can then drop
EXT4_STATE_DELALLOC_RESERVED.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2014-09-04 18:07:25 -04:00
Theodore Ts'o
71d4f7d032 ext4: remove metadata reservation checks
Commit 27dd438542 ("ext4: introduce reserved space") reserves 2% of
the file system space to make sure metadata allocations will always
succeed.  Given that, tracking the reservation of metadata blocks is
no longer necessary.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-07-15 06:02:38 -04:00
Namjae Jeon
e43bb4e612 ext4: decrement free clusters/inodes counters when block group declared bad
We should decrement free clusters counter when block bitmap is marked
as corrupt and free inodes counter when the allocation bitmap is
marked as corrupt to avoid misunderstanding due to incorrect available
size in statfs result.  User can get immediately ENOSPC error from
write begin without reaching for the writepages.

Cc: Darrick J. Wong<darrick.wong@oracle.com>
Reported-by: Amit Sahrawat <amit.sahrawat83@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
2014-06-26 10:11:53 -04:00
Stephen Hemminger
c197855ea1 ext4: make local functions static
I have been running make namespacecheck to look for unneeded globals, and
found these in ext4.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-05-12 10:50:23 -04:00
Darrick J. Wong
e674e5cbd0 ext4: fix block bitmap validation when bigalloc, ^flex_bg
On a bigalloc,^flex_bg filesystem, the ext4_valid_block_bitmap
function fails to convert from blocks to clusters when spot-checking
the validity of the bitmap block that we've just read from disk.  This
causes ext4 to think that the bitmap is garbage, which results in the
block group being taken offline when it's not necessary.  Add in the
necessary EXT4_B2C() calls to perform the conversions.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-05-12 10:17:55 -04:00
Darrick J. Wong
1beeef1b56 ext4: fix block bitmap initialization under sparse_super2
The ext4_bg_has_super() function doesn't know about the new rules for
where backup superblocks go on a sparse_super2 filesystem.  Therefore,
block bitmap initialization doesn't know that it shouldn't reserve
space for backups in groups that are never going to contain backups.
The result of this is e2fsck complaining about the block bitmap being
incorrect (fortunately not in a way that results in cross-linked
files), so fix the whole thing.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-05-12 10:16:06 -04:00
Azat Khuzhin
036acea2ce ext4: fix ext4_count_free_clusters() with EXT4FS_DEBUG and bigalloc enabled
With bigalloc enabled we must use EXT4_CLUSTERS_PER_GROUP() instead of
EXT4_BLOCKS_PER_GROUP() otherwise we will go beyond the allocated buffer.

$ mount -t ext4 /dev/vde /vde
[   70.573993] EXT4-fs DEBUG (fs/ext4/mballoc.c, 2346): ext4_mb_alloc_groupinfo:
[   70.575174] allocated s_groupinfo array for 1 meta_bg's
[   70.576172] EXT4-fs DEBUG (fs/ext4/super.c, 2092): ext4_check_descriptors:
[   70.576972] Checking group descriptorsBUG: unable to handle kernel paging request at ffff88006ab56000
[   72.463686] IP: [<ffffffff81394eb9>] __bitmap_weight+0x2a/0x7f
[   72.464168] PGD 295e067 PUD 2961067 PMD 7fa8e067 PTE 800000006ab56060
[   72.464738] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[   72.465139] Modules linked in:
[   72.465402] CPU: 1 PID: 3560 Comm: mount Tainted: G        W    3.14.0-rc2-00069-ge57bce1 #60
[   72.466079] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   72.466505] task: ffff88007ce6c8a0 ti: ffff88006b7f0000 task.ti: ffff88006b7f0000
[   72.466505] RIP: 0010:[<ffffffff81394eb9>]  [<ffffffff81394eb9>] __bitmap_weight+0x2a/0x7f
[   72.466505] RSP: 0018:ffff88006b7f1c00  EFLAGS: 00010206
[   72.466505] RAX: 0000000000000000 RBX: 000000000000050a RCX: 0000000000000040
[   72.466505] RDX: 0000000000000000 RSI: 0000000000080000 RDI: 0000000000000000
[   72.466505] RBP: ffff88006b7f1c28 R08: 0000000000000002 R09: 0000000000000000
[   72.466505] R10: 000000000000babe R11: 0000000000000400 R12: 0000000000080000
[   72.466505] R13: 0000000000000200 R14: 0000000000002000 R15: ffff88006ab55000
[   72.466505] FS:  00007f43ba1fa840(0000) GS:ffff88007f800000(0000) knlGS:0000000000000000
[   72.466505] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   72.466505] CR2: ffff88006ab56000 CR3: 000000006b7e6000 CR4: 00000000000006e0
[   72.466505] Stack:
[   72.466505]  ffff88006ab65000 0000000000000000 0000000000000000 0000000000010000
[   72.466505]  ffff88006ab6f400 ffff88006b7f1c58 ffffffff81396bb8 0000000000010000
[   72.466505]  0000000000000000 ffff88007b869a90 ffff88006a48a000 ffff88006b7f1c70
[   72.466505] Call Trace:
[   72.466505]  [<ffffffff81396bb8>] memweight+0x5f/0x8a
[   72.466505]  [<ffffffff811c3b19>] ext4_count_free+0x13/0x21
[   72.466505]  [<ffffffff811c396c>] ext4_count_free_clusters+0xdb/0x171
[   72.466505]  [<ffffffff811e3bdd>] ext4_fill_super+0x117c/0x28ef
[   72.466505]  [<ffffffff81391569>] ? vsnprintf+0x1c7/0x3f7
[   72.466505]  [<ffffffff8114d8dc>] mount_bdev+0x145/0x19c
[   72.466505]  [<ffffffff811e2a61>] ? ext4_calculate_overhead+0x2a1/0x2a1
[   72.466505]  [<ffffffff811dab1d>] ext4_mount+0x15/0x17
[   72.466505]  [<ffffffff8114e3aa>] mount_fs+0x67/0x150
[   72.466505]  [<ffffffff811637ea>] vfs_kern_mount+0x64/0xde
[   72.466505]  [<ffffffff81165d19>] do_mount+0x6fe/0x7f5
[   72.466505]  [<ffffffff81126cc8>] ? strndup_user+0x3a/0xd9
[   72.466505]  [<ffffffff8116604b>] SyS_mount+0x85/0xbe
[   72.466505]  [<ffffffff81619e90>] tracesys+0xdd/0xe2
[   72.466505] Code: c3 89 f0 b9 40 00 00 00 55 99 48 89 e5 41 57 f7 f9 41 56 49 89 ff 41 55 45 31 ed 41 54 41 89 f4 53 31 db 41 89 c6 45 39 ee 7e 10 <4b> 8b 3c ef 49 ff c5 e8 bf ff ff ff 01 c3 eb eb 31 c0 45 85 f6
[   72.466505] RIP  [<ffffffff81394eb9>] __bitmap_weight+0x2a/0x7f
[   72.466505]  RSP <ffff88006b7f1c00>
[   72.466505] CR2: ffff88006ab56000
[   72.466505] ---[ end trace 7d051a08ae138573 ]---
Killed

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-04-14 23:36:15 -04:00
Darrick J. Wong
2746f7a170 ext4: don't count free clusters from a corrupt block group
A bg that's been flagged "corrupt" by definition has no free blocks,
so that the allocator won't be tempted to use the damaged bg.
Therefore, we shouldn't count the clusters in the damaged group when
calculating free counts.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
2013-10-31 11:46:31 -04:00
Darrick J. Wong
bdfb6ff4a2 ext4: mark group corrupt on group descriptor checksum
If the group descriptor fails validation, mark the whole blockgroup
corrupt so that the inode/block allocators skip this group.  The
previous approach takes the risk of writing to a damaged group
descriptor; hopefully it was never the case that the [ib]bitmap fields
pointed to another valid block and got dirtied, since the memset would
fill the page with 1s.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 18:46:56 -04:00
Darrick J. Wong
163a203ddb ext4: mark block group as corrupt on block bitmap error
When we notice a block-bitmap corruption (because of device failure or
something else), we should mark this group as corrupt and prevent
further block allocations/deallocations from it. Currently, we end up
generating one error message for every block in the bitmap. This
potentially could make the system unstable as noticed in some
bugs. With this patch, the error will be printed only the first time
and mark the entire block group as corrupted. This prevents future
access allocations/deallocations from it.

Also tested by corrupting the block
bitmap and forcefully introducing the mb_free_blocks error:
(1) create a largefile (2Gb)
$ dd if=/dev/zero of=largefile oflag=direct bs=10485760 count=200
(2) umount filesystem. use dumpe2fs to see which block-bitmaps
are in use by largefile and note their block numbers
(3) use dd to zero-out the used block bitmaps
$ dd if=/dev/zero of=/dev/hdc4 bs=4096 seek=14 count=8 oflag=direct
(4) mount the FS and delete the largefile.
(5) recreate the largefile. verify that the new largefile does not
get any blocks from the groups marked as bad.
Without the patch, we will see mb_free_blocks error for each bit in
each zero'ed out bitmap at (4). With the patch, we only see the error
once per blockgroup:
[  309.706803] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 15: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.720824] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 14: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.732858] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.748321] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 13: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.760331] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.769695] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 12: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.781721] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.798166] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 11: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.
[  309.810184] EXT4-fs error (device sdb4) in ext4_free_blocks:4802: IO failure
[  309.819532] EXT4-fs error (device sdb4): ext4_mb_generate_buddy:735: group 10: 32768 clusters in bitmap, 0 in gd. blk grp corrupted.

Google-Bug-Id: 7258357

[darrick.wong@oracle.com]
Further modifications (by Darrick) to make more obvious that this corruption
bit applies to blocks only.  Set the corruption flag if the block group bitmap
verification fails.

Original-author: Aditya Kali <adityakali@google.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 17:35:51 -04:00
Darrick J. Wong
dbde0abed8 ext4: fix type declaration of ext4_validate_block_bitmap
The block_group parameter to ext4_validate_block_bitmap is both used
as a ext4_group_t inside the function and the same type is passed in
by all callers.  We might as well use the typedef consistently instead
of open-coding the 'unsigned int'.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 15:59:51 -04:00
Darrick J. Wong
48d9eb97dc ext4: error out if verifying the block bitmap fails
The block bitmap verification code assumes that calling ext4_error()
either panics the system or makes the fs readonly.  However, this is
not always true: when 'errors=continue' is specified, an error is
printed but we don't return any indication of error to the caller,
which is (probably) the block allocator, which pretends that the crud
we read in off the disk is a usable bitmap.  Yuck.

A block bitmap that fails the check should at least return no bitmap
to the caller.  The block allocator should be told to go look in a
different group, but that's a separate issue.

The easiest way to reproduce this is to modify bg_block_bitmap (on a
^flex_bg fs) to point to a block outside the block group; or you can
create a metadata_csum filesystem and zero out the block bitmaps.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 15:35:27 -04:00