linux-toradex.git/fs/ext4/ext4_jbd2.h, branch v4.4.79

ext4: do not perform data journaling when data is encrypted

2017-01-06T10:16:13+00:00

commit 73b92a2a5e97d17cc4d5c4fe9d724d3273fb6fd2 upstream.

Currently data journalling is incompatible with encryption: enabling both
at the same time has never been supported by design, and would result in
unpredictable behavior. However, users are not precluded from turning on
both features simultaneously. This change programmatically replaces data
journaling for encrypted regular files with ordered data journaling mode.

Background:
Journaling encrypted data has not been supported because it operates on
buffer heads of the page in the page cache. Namely, when the commit
happens, which could be up to five seconds after caching, the commit
thread uses the buffer heads attached to the page to copy the contents of
the page to the journal. With encryption, it would have been required to
keep the bounce buffer with ciphertext for up to the aforementioned five
seconds, since the page cache can only hold plaintext and could not be
used for journaling. Alternatively, it would be required to setup the
journal to initiate a callback at the commit time to perform deferred
encryption - in this case, not only would the data have to be written
twice, but it would also have to be encrypted twice. This level of
complexity was not justified for a mode that in practice is very rarely
used because of the overhead from the data journalling.

Solution:
If data=journaled has been set as a mount option for a filesystem, or if
journaling is enabled on a regular file, do not perform journaling if the
file is also encrypted, instead fall back to the data=ordered mode for the
file.

Rationale:
The intent is to allow seamless and proper filesystem operation when
journaling and encryption have both been enabled, and have these two
conflicting features gracefully resolved by the filesystem.

Fixes: 4461471107b7
Signed-off-by: Sergey Karamov 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: clean up feature test macros with predicate functions

2015-10-17T20:18:43+00:00

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

ext4: don't use MAXQUOTAS value

2014-09-11T15:15:15+00:00

MAXQUOTAS value defines maximum number of quota types VFS supports.
This isn't necessarily the number of types ext4 supports. Although
ext4 will support project quotas, use ext4 private definition for
consistency with other filesystems.

Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

ext4: make local functions static

2014-05-12T14:50:23+00:00

I have been running make namespacecheck to look for unneeded globals, and
found these in ext4.

Signed-off-by: Stephen Hemminger 
Signed-off-by: "Theodore Ts'o"

ext4: Fix misspellings using 'codespell' tool

2013-08-28T18:40:12+00:00

Signed-off-by: Anatol Pomozov 
Signed-off-by: "Theodore Ts'o"

ext4: use transaction reservation for extent conversion in ext4_end_io

2013-06-04T17:21:11+00:00

Later we would like to clear PageWriteback bit only after extent
conversion from unwritten to written extents is performed.  However it
is not possible to start a transaction after PageWriteback is set
because that violates lock ordering (and is easy to deadlock).  So we
have to reserve a transaction before locking pages and sending them
for IO and later we use the transaction for extent conversion from
ext4_end_io().

Reviewed-by: Zheng Liu 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

ext4: provide wrappers for transaction reservation calls

2013-06-04T16:37:50+00:00

Reviewed-by: Zheng Liu 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

ext4: improve credit estimate for EXT4_SINGLEDATA_TRANS_BLOCKS

2013-04-09T16:39:26+00:00

Estimate of 27 credits for allocation of a block in extent based inode
is unnecessarily high. We can easily argue 20 is enough.

Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

ext4: fix journal callback list traversal

2013-04-04T02:08:52+00:00

It is incorrect to use list_for_each_entry_safe() for journal callback
traversial because ->next may be removed by other task:
->ext4_mb_free_metadata()
  ->ext4_mb_free_metadata()
    ->ext4_journal_callback_del()

This results in the following issue:

WARNING: at lib/list_debug.c:62 __list_del_entry+0x1c0/0x250()
Hardware name:
list_del corruption. prev->next should be ffff88019a4ec198, but was 6b6b6b6b6b6b6b6b
Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod
Pid: 16400, comm: jbd2/dm-1-8 Tainted: G        W    3.8.0-rc3+ #107
Call Trace:
 [] warn_slowpath_common+0xad/0xf0
 [] warn_slowpath_fmt+0x46/0x50
 [] ? ext4_journal_commit_callback+0x99/0xc0
 [] __list_del_entry+0x1c0/0x250
 [] ext4_journal_commit_callback+0x6f/0xc0
 [] jbd2_journal_commit_transaction+0x23a6/0x2570
 [] ? try_to_del_timer_sync+0x82/0xa0
 [] ? del_timer_sync+0x91/0x1e0
 [] kjournald2+0x19f/0x6a0
 [] ? wake_up_bit+0x40/0x40
 [] ? bit_spin_lock+0x80/0x80
 [] kthread+0x10e/0x120
 [] ? __init_kthread_worker+0x70/0x70
 [] ret_from_fork+0x7c/0xb0
 [] ? __init_kthread_worker+0x70/0x70

This patch fix the issue as follows:
- ext4_journal_commit_callback() make list truly traversial safe
  simply by always starting from list_head
- fix race between two ext4_journal_callback_del() and
  ext4_journal_callback_try_del()

Signed-off-by: Dmitry Monakhov 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Jan Kara 
Cc: stable@vger.kernel.com

ext4: fix the number of credits needed for acl ops with inline data

2013-02-09T20:23:03+00:00

Operations which modify extended attributes may need extra journal
credits if inline data is used, since there is a chance that some
extended attributes may need to get pushed to an external attribute
block.

Changes to reflect this was made in xattr.c, but they were missed in
fs/ext4/acl.c.  To fix this, abstract the calculation of the number of
credits needed for xattr operations to an inline function defined in
ext4_jbd2.h, and use it in acl.c and xattr.c.

Also move the function declarations used in inline.c from xattr.h
(where they are non-obviously hidden, and caused problems since
ext4_jbd2.h needs to use the function ext4_has_inline_data), and move
them to ext4.h.

Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Tao Ma 
Reviewed-by: Jan Kara