Commit Graph

1422 Commits (460c0af190ea11c903dd0e0730cfc7c3d279bcc8)

Author SHA1 Message Date
Darrick J. Wong ba380eea99 libext2fs: sort keys for xattr blocks
Richard Purdie reports that libext2fs doesn't sort attribute keys in
the xattr block correctly, causing the kernel to return -ENODATA when
querying attributes that should be there.  Therefore, sort attributes
so that whatever ends up in the xattr block is sorted according to
what the kernel expects.

Cc: Darren Hart <dvhart@linux.intel.com>
Reported-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Tested-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 20:08:53 -05:00
Darrick J. Wong 2b8772f522 tests: check proper operation of metadata_csum_seed
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 20:08:53 -05:00
Darrick J. Wong 2ed0adbce6 libext2fs: store checksum seed in superblock
Allow the filesystem to store the metadata checksum seed in the
superblock and add an incompat feature to say that we're using it.
This enables tune2fs to change the UUID on a mounted metadata_csum
FS without having to (racy!) rewrite all disk metadata.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 20:08:52 -05:00
Li Xi e1cec4464b Add inherit flags for project quota
This patch add EXT4_PROJINHERIT_FL to enable inherit feature for
project ID. If an directory has its inherit flag set, all its
newly created children will inherit its project ID. Conversely,
new inodes will get a default project ID (i.e. zero). Also, no
hard link or rename is permitted if the directory and child has
different project ID.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 17:33:45 -05:00
Li Xi 080e09b46f Add project quota support
This patch adds project quota support. An new quota type PRJQUOTA(2)
is added. EXT4_PRJ_QUOTA_INO(11) is reserved for project quota inode.
The super block reservers an field s_prj_quota_inum for saving
project quota inode. And each inode adds an internal field i_projid
for saving its project ID.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 17:33:39 -05:00
Li Xi 0c18d0368a Add project feature flag EXT4_FEATURE_RO_COMPAT_PROJECT
This patch add project feature flag EXT4_FEATURE_RO_COMPAT_PROJECT.
Project feature is a read-only compat feature. Thus, an ext4 file
system with project feature enabled could only be read by ext4
kernel module without project feature support.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-06 15:56:28 -05:00
Theodore Ts'o d030908bfc ext2fs: work around FreeBSD header breakage
FreeBSD 10.2 will blow up compiling its own header files in sys/file.h
if _XOPEN_SOURCE is defined.

In file included from tdb.c:59:
/usr/include/sys/file.h:209:2: error: unknown type name 'u_int'
        u_int   xf_flag;        /* flags (see fcntl.h) */
                ^
1 error generated.

This is despite the fact that POSIX.1 requires comforming applications
to define _XOPEN_SOURCE (to different numbers depending on the version
of POSIX.1 the program is expecting to work against).  See section
2.2.1 in POSIX.1 for chapter and verse.

Work around this by removing the _XOPEN_SOURCE declaration.  This will
cause compiler warnings (and will cause builds against some versions
of Solaris to break), so only do this for FreeBSD.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-01-01 20:12:22 -05:00
Theodore Ts'o 94676ef2b3 Merge branch 'maint' into next 2015-11-30 18:16:36 -05:00
Andreas Dilger e158db5377 libext2fs: fix block-mapped file punch
If ext2fs_punch() was called with "end = ~0ULL" to indicate truncate
to the end of file it tried to compute "count" for ext2fs_punch_ind()
based on "start" and "end", but incorrectly passed "count = ~0U" even
when "start" was non-zero, causing an overflow in some cases.

The calling convention for ext2fs_punch_ind() was also gratuitously
different from ext2fs_punch() and ext2fs_punch_extent(), passing
"count" instead of "end" as the last parameter.  Fix this by passing
it "end" like the other functions, and handle "count" internally.

Add checks to ext2fs_punch_ind() if "end" is at or beyond the 2^32
indirect block limit so the 32-bit internal variables don't overflow.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-11-30 15:26:21 -05:00
Andreas Dilger f449486d63 libext2fs: fix tst_badblocks buffer overrun
The test2[] array is not 0-terminated and the create_test_list() for
loop does not terminate properly at the end of this array, but
continues until it hits the 0 at the end of test3[].

Reported-by: Hanno Boeck <hanno@hboeck.de>
Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=104311
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-11-30 12:09:44 -05:00
Theodore Ts'o 188960ea4b debugfs: add support to properly set and display extended timestamps
This code is partially derived from patches from David Turner to allow
debugfs to properly support extended timestamps.

Cc: David Turner <novalis@novalis.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2015-11-30 11:42:00 -05:00
Darrick J. Wong 7dce0c06e5 libext2fs: fix parents when modifying extents
In ext2fs_extent_set_bmap() and ext2fs_punch_extent(), fix the parents
when altering either end of an extent so that the parent nodes reflect
the added mapping.

There's a slight complication to using fix_parents: if there are two
mappings to an lblk in the tree, the value of handle->path->curr can
point to either extent afterwards), which is documented in a comment.

Some additional color commentary from Darrick:

  In the _set_bmap() case, I noticed that the "remapping last block in
  extent" case would produce symptoms if we are trying to remap a
  block from "extent" to "next_extent", and the two extents are
  pointed to by different index nodes.  _extent_replace(...,
  next_extent) updates e_lblk in the leaf extent, but because there's
  no _extent_fix_parents() call, the index nodes never get updated.

  In the _punch_extent() case, we conclude that we need to split an
  extent into two pieces since we're punching out the middle.  If the
  extent is the last extent in the block, the second extent will be
  inserted into a new leaf node block.  Without _fix_parents(), the
  index node doesn't seem to get updated.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2015-11-16 06:08:17 -05:00
Darrick J. Wong 77b3e98718 libext2fs: 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>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-24 00:34:09 -04:00
Darrick J. Wong 03940aac54 libext2fs: automatically enable meta_bg to avoid filling up BG 0
If during formatting we'd lose more than 75% a block group to group
descriptors and other metadata, enable the meta_bg feature.  This
enables us to create >500T filesystems with default options.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-24 00:30:10 -04:00
Darrick J. Wong 1abdd04eb1 libext2fs: fix maximum bg overhead calculation with meta_bg enabled
When meta_bg is enabled at mkfs time, we put at most one group
descriptor block in each blockgroup.  Unfortunately, the calculation
of max overhead per bg doesn't know this, so mkfs fails when it isn't
strictly necessary.  Fix it, since Dave reported that he couldn't
create a 500TB ext4 filesystem.

Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-24 00:24:57 -04:00
Theodore Ts'o e3dd5c6f1a e2fsck: check for encrypted directory entries with too-short file names
If there are directory entries with file names which are less than 16
bytes, it turns out that passing less than the crypto block size to
the kernel's crypto layer will cause the kernel to crash.

However, since there never should be encrypted directory entries where
the file name is less than 16 bytes (the AES block size), change
e2fsck to offer to address this corruption by deleting the directory
entry.

(We need to checks for this condition into the kernel as well.)

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-16 18:02:58 -04:00
Theodore Ts'o 4e222d9b88 misc: cleanup gcc -Wall warnings
Also change ext2fs_symlink() so that the target parameter is a const
char *, thus promising that we will never change the incoming string.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-13 15:36:12 -04:00
Theodore Ts'o cf491d3a64 Eliminate unused variable and unused label warnings from Android build
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-13 10:47:16 -04:00
Theodore Ts'o 25f291c9b3 Eliminate unused parameter warnings from Android build
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-13 09:12:23 -04:00
Theodore Ts'o aee40b870c Eliminate unused function warnings from Android build
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 23:09:15 -04:00
Theodore Ts'o f1644c324b Eliminate doubly defined _LARGEFILE_SOURCE warning
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 22:54:37 -04:00
Theodore Ts'o 3dca12fb62 Move dict.c from e2fsck to lib/support
The quota code required that we included dict.o in libsupport.a, so we
might as well just move dict.c and dict.h to lib/support, and then
have e2fsck use the version of dict.c in libsupport.a.  This
simplifies the build system and eliminates having two identical copies
of dict.o floating around in the build tree.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 22:43:31 -04:00
Theodore Ts'o 99ceb8ec1a Move the check_plausibility() function from misc to lib/support
The check_plausibility() function is now used all over the place, so
we should move the plausible.c file to lib/support and remove the
special case handling for that file that had been in the build system.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 22:01:17 -04:00
Theodore Ts'o 273c2c5dfd tune2fs: allow tune2fs to be built as a static library for Android
Sync up with aosp's e2fsprogs commits:

    d25948b9b4a9e361ef071dc8175df0407f60b7e0
    e59f7c7cedb1e07eb4dbbb66e115c14faea19f19

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 20:21:17 -04:00
Theodore Ts'o 0a332f42f9 Add fallocate.c to lib/exte2fs/Android.mk
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 16:10:58 -04:00
Theodore Ts'o f34af41b72 rename libquota.a to libsupport.a
We will be using libsupport.a for e2fsprogs's internal support
functions.  It will contain the quota support functions, but we will
also be moving code such as profile.c and plausible.c to libsupport.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-12 16:09:22 -04:00
Theodore Ts'o 9e8fcd6e01 configure: remove support to disable quota support
For the 1.43 release, quota support will be the default.  It's much
simpler if we don't try to make quota support optional.  This was done
originally because the quota feature wasn't fully tested.  It is now,
so we can remove this as an option.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-07-03 22:02:30 -04:00
Theodore Ts'o 8f8511aba0 libext2fs: fix gcc -Wall nits
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-21 20:15:52 -04:00
Theodore Ts'o 74f2c4aa18 fix diet libc build breaks for e4crypt and fallocate
Diet libc doesn't support syscall correctly, but it does have
add_key() and keyctl() in libc (although glibc does not).  So change
e4crypt to use add_key() and keyctl() directly if they are available.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-19 19:28:25 -04:00
Darrick J. Wong eeb2bb68f8 libext2fs: remove unnecessary undo file flush calls
Remove all flushes of the undo file except for the one that happens just
prior to the file being closed; it seems that the arbitrary flushes
aren't sufficiently useful.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-10 20:08:33 -04:00
Darrick J. Wong 4f868703f6 libext2fs: use fallocate for creating journals and hugefiles
Use the new fallocate API for creating the journal and the mk_hugefile
feature.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-10 19:57:52 -04:00
Darrick J. Wong 5aad5b8e0e libext2fs: implement fallocate
Create a library function to perform fallocation on arbitrary files.
This is a bit more intense than Ted's original mk_hugefiles
implementation since we have to honor any blocks that may already be
allocated to the file.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-10 19:56:46 -04:00
Darrick J. Wong 647e878615 libext2fs: add new hooks to support large allocations
Add a new get_alloc_blocks hook and a block_alloc_stats_range hook so
that e2fsck can capture allocation requests spanning more than a
block to its block_found_map.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-10 14:13:25 -04:00
Theodore Ts'o 766c142891 libext2fs: fix ext2fs_close() when MMP is not enabled
If MMP support is not configured, then ext2fs_mmp_stop() will always
return the error EXT2_ET_OP_NOT_SUPPORTED.  Unfortunately,
ext2fs_close() and tune2fs call ext2fs_mmp_stop() unconditionally.  So
if the file system does not have MMP enabled, fix ext2fs_mmp_stop() to
return success even if CONFIG_MMP is not enabled, so that
ext2fs_close() and tune2fs doesn't fail for no good reason.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-25 22:18:43 -04:00
Theodore Ts'o 81f95d43d5 libext2fs, libe2p, misc: git rid of jfs_user.h
Having multiple versions of jfs_user.h was confusing the Android
build.  Clean up things by removing the lib/ext2fs/jfs_user.h and
misc/jfs_user.h and simplifying how we emulate the kernel
infrastructure needed by journal replay code and removing the
kernel-specific lines from kernel-jbd.h.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-25 21:18:15 -04:00
Theodore Ts'o 2df733facd Update Android build files so the 1.43 branch builds on AOSP
Recent changes in the 1.43 branch as well as the latest AOSP caused
the Android build to break; fix them.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-25 20:25:28 -04:00
Darrick J. Wong 5a98026443 libext2fs: find/alloc a range of empty blocks
Provide a function that, given a goal pblk and a range, will try to
find a run of free blocks to satisfy the allocation.  By default the
function will look anywhere in the filesystem for the run, though this
can be constrained with optional flags.  One flag indicates that the
range must start at the goal block; the other flag indicates that we
should not return a range shorter than len.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-16 21:02:18 -04:00
Darrick J. Wong 60a212f773 libext2fs: support allocating uninit blocks in bmap2()
As part of supporting fallocate-like functionality, extend
ext2fs_bmap() with two flags -- BMAP_UNINIT and BMAP_ZERO.  The first
will cause it to mark/set a block uninitialized, if it's part of an
extent based file.  For a block mapped file, the mapping is put in,
but there is no way to remember the uninitialized status.  The second
flag causes the block to be zeroed to support the use case of
emulating uninitialized blocks on a block-map file by zeroing them.

Eventually fallocate or fuse2fs or somebody will use these.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-16 20:54:29 -04:00
Darrick J. Wong 5e48a20d8d undo-io: write out index block after every write
Write out the undo file's index block after writing a block to the
undo file.  This ensures that we always have a consistent undo file
in the page cache, even if the program crashes.  When we fill up a
key block in the undo file, we'll call fsync to force the whole
thing to storage; this should happen about every 256 blocks given
the usual 4K block size.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-16 19:52:06 -04:00
Darrick J. Wong ce9b74ab4f e2fsck: optionally create an undo file
Provide the user with an option to create an undo file so that they
can roll back a failed repair operation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:40:49 -04:00
Darrick J. Wong dc248a10ca libext2fs: support atexit cleanups
Use the atexit() function to provide a means for the library to clean
itself up on program exit.  This will be used by the undo IO manager
to flush the undo file state to disk if the program should terminate
without closing the io channel, since most e2fsprogs clients will
simply exit() when they hit errors.

This won't help for signal termination; client programs must set
up signal handlers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:40:34 -04:00
Darrick J. Wong 4892bce3c4 e2undo: ditch tdb file, write everything to a flat file
The existing undo file format (which is based on tdb) has many
problems.  First, its comparison of superblock fields is ineffective,
since the last mount time is only written by the kernel, not the tools
(which means that undo files can be applied out of order, thus
corrupting the filesystem); block numbers are written in CPU byte
order, which will cause silent failures if an undo file is moved from
one type of system to another; using the tdb database costs us an
enormous amount of CPU overhead to maintain the key data structure,
and finally, the tdb database is unable to deal with databases larger
than 2GB.  (Upstream tdb 1.2.12 can handle 4GB, but upgrading a 2TB FS
to 64bit,metadata_csum easily produces 2.9GB of undo files, so we
might as well move off of tdb now.)

The last problem is fatal if you want to use tune2fs to turn on
metadata checksumming, since that rewrites every block on the
filesystem, which can easily produce a many-gigabyte undo file, which
of course is unreadable and therefore the operation cannot be undone.

Therefore, rip all of that out in favor of writing to a flat file.
Old blocks are appended to a file and the index is written to the end
when we're done.  This implementation is much faster than wasting a
considerable amount of time trying to maintain a hash index, which
drops the runtime overhead of tune2fs -O metadata_csum from ~45min
to ~20 seconds on a 2TB filesystem.

I have a few reasons that factored in my decision not to repurpose the
jbd2 file format for undo files.  First, undo files are limited to
2^32 blocks (16TB) which some day might not serve us well.  Second,
the journal block size is tied to the file system block size, but
mke2fs wants to be able to back up big chunks of old device contents.
This would require large changes to the e2fsck journal replay code,
which itself is derived from the kernel jbd2 driver, which I'd rather
not destabilize.  Third, I want to require undo files to store the FS
superblock at the end of undo file creation so that e2undo can be
reasonably sure that an undo file is supposed to apply against the
given block device, and doing so would require changes to the jbd2
format.  Fourth, it didn't seem like a good idea that external
journals should resemble undo files so closely.

v2: Provide a state bit that is only set when the undo channel is
closed correctly so we can warn the user about potentially incomplete
undo files.  Straighten out the superblock handling so that undo files
won't be confused for real ext* FS images.  Record multi-block runs in
each block key to reduce overhead even further.  Support reopening an
undo file so that we can combine multiple FS operations into one
(overall smaller) transaction file, which will be easier to manage.
Flush the undo index data if the program should terminate
unexpectedly.  Update the ext4 superblock bits if errors or -f is
found to encourage fsck to do a full run the next time it's invoked.
Enable undoing the undo.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:40:16 -04:00
Darrick J. Wong 3a82e80c55 undo-io: use a bitmap to track what we've already written
It's really inefficient to (ab)use the TDB key store as a bitmap to
find out if we've already written a block to the undo file, because
the tdb code is reads the database key btree disk blocks for *every*
query.  Changing that logic to a bitmap reduces overhead by a large
margin -- the overhead of using undo_io while converting a 2TB FS to
metadata_csum is reduced from 55 minutes to 45.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:39:33 -04:00
Darrick J. Wong 344cd5325b undo-io: be more flexible about setting block size
Most of the e2fsprogs utilities set the IO block size multiple times
(once to 1k to read the superblock, then again to set the real block
size if we find a real superblock).  Unfortunately, the undo IO
manager only lets the block size be set once.  For the non-mke2fs
utilities we'd rather catch the real block size and use that.  mke2fs
of course wants to use a really large block size since it's probably
writing a lot of data.

Therefore, if we haven't written any blocks to the undo file, it's
perfectly fine to allow block size changes.  For mke2fs, we'll modify
the IO channel option that lets us set the huge size to lock that
in place.  This greatly reduces index overhead for undo files for
e2fsck/tune2fs/resize2fs while continuing the practice of reducing
it even more for mke2fs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:39:13 -04:00
Darrick J. Wong c866515f02 undo-io: add new calls to and speed up the undo io manager
Implement pass-through calls for discard, zero-out, and readahead in
the IO manager so that we can take advantage of any underlying
support.

Furthermore, improve tdb write-out speed by disabling locking and only
fsyncing at the end -- we don't care about locking because having
multiple writers to the undo file will produce an undo database full
of garbage blocks; and we only need to fsync at the end because if we
fail before the end, our undo file will lack the necessary superblock
data that e2undo requires to do replay safely.  Without this, we call
fsync four times per tdb update(!)  This reduces the overhead of using
undo_io while converting a 2TB FS to metadata_csum from 3+ hours to 55
minutes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:38:34 -04:00
Theodore Ts'o c46b57bc9d ext2fs: fix "make check" by allowing EXT2FS_SHA256_LENGTH to be defined
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-05 10:01:40 -04:00
Theodore Ts'o 437651ad23 Update ext4 encryption format to final v4.1 version
The directory hash is now calculated using the on-disk encrypted
filename, and we no longer use the digest encoding or the SHA-256
encoding, so remove them from the ext2fs library until there is some
reason we need them.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-03 17:01:59 -04:00
Darrick J. Wong a5abfe0382 e2fsck: read-ahead metadata during passes 1, 2, and 4
e2fsck pass1 is modified to use the block group data prefetch function
to try to fetch the inode tables into the pagecache before it is
needed.  We iterate through the blockgroups until we have enough inode
tables that need reading such that we can issue readahead; then we sit
and wait until the last inode table block read of the last group to
start fetching the next bunch.

pass2 is modified to use the dirblock prefetching function to prefetch
the list of directory blocks that are assembled in pass1.  We use the
"iterate a subset of a dblist" and avoid copying the dblist.  Directory
blocks are fetched incrementally as we walk through the directory
block list.  In previous iterations of this patch we would free the
directory blocks after processing, but the performance hit to e2fsck
itself wasn't worth it.  Furthermore, it is anticipated that most
users will then mount the FS and start using the directories, so they
may as well remain in the page cache.

pass4 is modified to prefetch the block and inode bitmaps in
anticipation of pass 5, because pass4 is entirely CPU bound.

In general, these mechanisms can decrease fsck time by 10-40%, if the
host system has sufficient memory and the storage system can provide a
lot of IOPs.  Pretty much any storage system capable of handling
multiple IOs in-flight at any time will see a fairly large performance
boost.  (Single-issue USB mass storage disks seem to suffer badly.)

By default, the readahead buffer size will be set to the size of a block
group's inode table (which is 2MiB for a regular ext4 FS).  The -E
readahead_kb= option can be given to specify the amount of memory to
use for readahead or zero to disable it entirely; or an option can be
given in e2fsck.conf.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-21 10:40:21 -04:00
Darrick J. Wong 79614b2709 libext2fs/e2fsck: provide routines to read-ahead metadata
This patch adds to e2fsck the ability to pre-fetch metadata into the
page cache in the hopes of speeding up fsck runs.  There are two new
functions -- the first allows a caller to readahead a list of blocks,
and the second is a helper function that uses that first mechanism to
load group data (bitmaps, inode tables).

These new e2fsck routines require the addition of a dblist API to
allow us to iterate a subset of a dblist.  This will enable
incremental directory block readahead in e2fsck pass 2.

There's also a function to estimate the readahead given a FS.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-21 10:40:15 -04:00
Theodore Ts'o a6721909c2 Revert "libext2fs: encrypted symlinks are never fast"
This reverts commit ae73e88e82.

The latest kernel patches will now create fast encrypted symlinks

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 18:05:07 -04:00
Theodore Ts'o fc898cb99b Reserve superblock fields s_lpf_ino and s_encryption_level
The s_lpf_ino field is intended to store the location of the lost and
found directory if the root directory becomes encrypted (which is not
yet supported).  The s_encryption_level field is designed to allow
support for future changes in the on-disk ext4 encryption format while
this feature under development, without having to burn a large number
of bits in the incompat feature flag.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 08:51:53 -04:00
Theodore Ts'o 4a05268cf8 Remove compression support
The compression patches were an out-of-kernel patch set that was (a)
only available for ext2, (b) something that was never could be
stablized due to file system corruption, and (c) the most recent
patches were for 3.1, last updated in 2011.

The history of the compression patches has been a bit checkered.
There is a long history here at http://e2compr.sourceforge.net which
lists the perspective of the people working on it from the e2compr
side.

From the ext2/3/4 mainline developers' perspective, initial
compression support was added to e2fsprogs in 2000 (in the Linux 2.2
era), but due to stability concerns the kernel patches were never
merged into the mainline kernel.  While there were some sporadic
efforts to try to get the ext2 compression patches working in the 2.4
and 2.6 era, by that time mainline work had moved on to ext4, and the
e2compr approach could only work with 32-bit block numbers and
indirect mapped files.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 08:42:40 -04:00
Theodore Ts'o f7257a93f9 Change filename encryption to use CTS mode
Previously we were using a weird hybrid CBC/CTS.  Switch things so we
are using straight CTS; this corresponds to changes made in the latest
ext4 encryption patches.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-05 20:39:57 -04:00
Theodore Ts'o 8afaf3be33 libext2fs: fix bug in ext2fs_digest_encode()
The ext2fs_digest_encode() function was broken for any input which was
a multiple of 3.  Previously we never hit that case, so we never
noticed it was busted.  Also fix up the unit test so future problems
like this get noticed quickly.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-05 20:35:50 -04:00
Theodore Ts'o 4fb758aa4b Clean up and fix Android build files
Add missing new lib/ext2fs source files that were added for encryption
support.  Also move configuration #define's from individual Android.mk
to the android_config.h file, since we've moved away from specifying
configuration #define's on the command-line upstream.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-30 14:50:55 -04:00
Darrick J. Wong ce93d0ea3d libext2fs: zero hash in ibody extended attributes
The kernel never updates the extended attribute hash value for
attributes stored in the inode.  However, fsck has always checked this
value (if it's nonzero) and will complain if the hash doesn't match
the xattr.  Therefore, always zero the hash value when writing to
in-ibody xattrs to avoid creating "corrupt" attribute errors
downstream.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-29 00:12:53 -04:00
Darrick J. Wong fae2467fb6 libext2fs: ext2fs_new_block2() should call alloc_block hook
If ext2fs_new_block2() is called without a specific block map, we
should call the alloc_block hook before checking fs->block_map.  This
helps us to avoid a bug in e2fsck where we need to allocate a block
but instead of consulting block_found_map, we use the FS bitmaps,
which (prior to pass 5) could be wrong.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-28 23:58:20 -04:00
Darrick J. Wong 3d28f54589 libext2fs: zero blocks via FALLOC_FL_ZERO_RANGE in ext2fs_zero_blocks
Plumb a new call into the IO manager to support translating
ext2fs_zero_blocks calls into the equivalent FALLOC_FL_ZERO_RANGE
fallocate flag primitive when possible.  This patch provides _only_
support for file-based images.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-28 23:08:25 -04:00
Theodore Ts'o 41f2210131 Add support for a password salt stored in the superblock
Previously, e4crypt required the user to manually specify the salt
used for their passphrase.  This was user unfriendly to say the least.
The e4crypt program can now request the salt using an ioctl, which
will automatically generate the salt if necessary, and keep it in the
ext4 superblock.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-28 20:15:02 -04:00
Ildar Muslukhov bfa4b350b1 misc: add e4crypt tool
This patch adds new e4crypt tool for encryption management in the ext4
filesystem.

Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-26 09:30:03 -04:00
Theodore Ts'o c4241cf50a libext2fs: fix blocksize for SHA512
The blocksize of SHA512 is 128 bytes, not 512.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-26 00:17:48 -04:00
Ildar Muslukhov bbb859496a misc: teach mke2fs to create encrypted file systems
Also enable support for encryption in e2fsprogs.

Signed-off-by: Ildar Muslukhov <muslukhovi@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-08 23:29:04 -04:00
Theodore Ts'o 6a5bdaf73d libext2fs: fix up ext2fs_sha256() and ext2fs_sha512()
Add const annotation to the input pointers; also run the tst_sha256
and tst_sha512 unit tests on a "make check".

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-08 18:19:05 -04:00
Theodore Ts'o bf34b4af70 libext2fs: add ext2fs_digest_encode()
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-08 18:15:47 -04:00
Theodore Ts'o ae73e88e82 libext2fs: encrypted symlinks are never fast
Teach ext2fs_inodes_has_valid_blocks2() that encrypted symlinks always
use an external block (i.e., we never try to store the symlink in the
i_blocks[] array if it is encrypted).

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-03-01 16:58:46 -05:00
Theodore Ts'o 321f3446f3 Add files to build on Android
The Android.mk files were taken from the Android AOSP sources, and
updated for the 1.43 next branch.  The intention is that this will
allow the repository which is currently located in external/e2fsprogs
with one which is based off of the upstream e2fsprogs.  Right now
external/e2fsprogs was not created using "git clone", so it means that
git merges don't work.  After the external/e2fsprogs Android
repository is replaced, with one based off the upstream repository,
Android will be able to synchronize with the upstream repository by
pulling and merging from upstream, and then running the script
"./util/gen-android-files" to update any generated files.  (This is
necessary because in the Android build system, the Android.mk files
are rather stylized and don't make it easy to run arbitrary shell
scripts during the build phase.)

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2015-03-01 15:45:11 -05:00
Theodore Ts'o 52a06740ef libext2fs: make sure dirent functions have prototypes if inline is disabled
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-02-23 23:00:17 -05:00
Theodore Ts'o 569ee9020d libext2fs: add functions for sha256 and sha512
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-02-23 22:38:46 -05:00
Theodore Ts'o 8b39e4cf77 Add support for the read-only feature
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-02-23 13:04:47 -05:00
Theodore Ts'o ad5d05d645 Merge branch 'maint' into next 2015-02-16 10:17:21 -05:00
Theodore Ts'o 49d0fe2a14 libext2fs: fix potential buffer overflow in closefs()
The bug fix in f66e6ce4446: "libext2fs: avoid buffer overflow if
s_first_meta_bg is too big" had a typo in the fix for
ext2fs_closefs().  In practice most of the security exposure was from
the openfs path, since this meant if there was a carefully crafted
file system, buffer overrun would be triggered when the file system was
opened.

However, if corrupted file system didn't trip over some corruption
check, and then the file system was modified via tune2fs or debugfs,
such that the superblock was marked dirty and then written out via the
closefs() path, it's possible that the buffer overrun could be
triggered when the file system is closed.

Also clear up a signed vs unsigned warning while we're at it.

Thanks to Nick Kralevich <nnk@google.com> for asking me to look at
compiler warning in the code in question, which led me to notice the
bug in f66e6ce444.

Addresses: CVE-2015-1572

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-02-11 15:06:18 -05:00
Darrick J. Wong 4a3dc1f0b6 e2fsck: salvage under-sized dirents by removing them
If the directory processing code ends up pointing to a directory entry
that's so close to the end of the block that there's not even space
for a rec_len/name_len, just substitute dummy values that will force
e2fsck to extend the previous entry to cover the remaining space.  We
can't use the helper methods to extract rec_len because that's reading
off the end of the buffer.

This isn't an issue with non-inline directories because the directory
check buffer is zero-extended so that fsck won't blow up.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-29 11:09:07 -05:00
Darrick J. Wong 5f0164b3a4 libext2fs: fix tdb.c mmap leak
When undoing an expansion of an mmap'd database while cancelling a
transaction, the tdb code prematurely decreases the variable that
tracks the file size, which leads to a region leak during the
subsequent unmap.  Fix this by maintaining a separate counter for the
region size.

(This is probably unnecessary since e2undo was the only user of tdb
transactions, but I suppose we could be proactive.)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-27 13:10:39 -05:00
Darrick J. Wong 2c741a8afc libext2fs: strengthen i_extra_isize checks when reading/writing xattrs
Strengthen the i_extra_isize checks to look for obviously too-small
values before trying to operate on inode EAs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-27 13:10:21 -05:00
Darrick J. Wong f99143146a libext2fs: avoid pointless EA block allocation
Use qsort to move the inlinedata attribute to the front of the list
and the empty entries to the end.  Then we can use handle->count to
decide if we're done writing xattrs, which helps us to avoid the
situation where we're midway through the attribute list, so we
allocate an EA block to store more, but have no idea that there's
actually nothing left in the list.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-27 13:09:52 -05:00
Darrick J. Wong 366d299fe7 libext2fs: initialize i_extra_isize when writing EAs
If i_extra_isize is zero when we try to write extended attributes,
we'll end up writing the EA magic into the i_extra_isize field, which
causes a subsequent crash on big endian systems (when we try to write
0xEA02 bytes past the inode!).  Therefore when the field is zero, set
i_extra_isize to the desired extra_isize size, zero those bytes, and
write the EAs after the end of the extended inode.

v2: Don't bother if we have 128b inodes, and ensure that the value
is 32b-aligned so that the EA magic starts on a 32b boundary.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-27 10:59:19 -05:00
Theodore Ts'o 22f22ab1d2 Reserve the codepoints for the new INCOMPAT feature ENCRYPT
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-26 10:27:41 -05:00
Theodore Ts'o 560080272f Merge branch 'maint' into next 2015-01-19 16:37:04 -05:00
Darrick J. Wong c916e5248b Fix clang warning and a resource leak
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-01-19 16:31:49 -05:00
Theodore Ts'o 9a32411732 Merge branch 'maint' into next
Conflicts:
	lib/ext2fs/inode.c
2014-12-25 23:43:10 -05:00
Theodore Ts'o 13f450addb libext2fs: add sanity check for an invalid itable_used value in inode scan code
If the number of unused inodes is greater than number of inodes a
block group, this can cause an e2fsck -n run of the file system to
crash.

We should add more checks to e2fsck to detect this case directly, but
this will at least protect progams (tune2fs, dump, etc.) which use the
inode_scan abstraction from crashing on an invalid file system.

Addresses-Debian-Bug: #773795

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-25 23:29:19 -05:00
Darrick J. Wong 413b5c76d8 libext2fs: speed up the max extent depth api call
The maximum extent tree depth really only depends on the filesystem
block size, so cache the last result if possible.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-15 12:26:57 -05:00
Darrick J. Wong ffe1b28dea libext2fs: add a way to check the theoretical maximum extent tree depth
Add an API so that client programs can discover a reasonable maximum
extent tree depth.  This will eventually be used by e2fsck as one of
the criteria to decide if an extent-based file should have its extent
tree rebuilt.

Turn some related magic numbers into constants while we're at it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-13 21:13:40 -05:00
Darrick J. Wong 6509eebb63 libext2fs: set interior tree block goal more intelligently
When we're splitting an extent node, try to allocate the new interior
tree block just prior to the first extent in the block we're trying to
split.  The previous logic only set a goal block if we had to split
both the current node and its parent, which is somewhat infrequent.
When that would happen, the goal would start at zero, leading to poor
locality.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-13 20:14:14 -05:00
Darrick J. Wong 7b486ec08c libext2fs: find inode goal when allocating blocks
Try to be a little smarter about where we go to allocate blocks for a
inode.  For a given inode and logical offset, set the goal as if the
file were physically continuous.  If it's bmapped, just start looking
at wherever lblk 0 is.  If that's not possible (the file has no
lblk>pblk mappings, inline data, etc.) then start looking in the
inode's block group.

[ Fixed memory leak --tytso ]

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-13 20:07:13 -05:00
Theodore Ts'o bc57b123d6 libext2fs: use block_buf in ext2fs_alloc_block2() if it is provided
If the caller supplies a buffer to ext2fs_alloc_block2(), use it
instead of calling ext2fs_zero_blocks2().

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-12 22:12:45 -05:00
Darrick J. Wong 0a92af260d libext2fs: use a dynamically sized block zeroing buffer
Dynamically grow the block zeroing buffer to a maximum of 4MB, and
allow callers to provide their own zeroed buffer in
ext2fs_zero_blocks2().

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-12 19:28:35 -05:00
Dmitry Monakhov e50e985d6a ext2fs: fix integer overflow in rb_get_bmap_range
bmap_rb_extent is defined as __u64:blk __u64:count.  So count can
exceed INT_MAX on populated filesystems.

TESTCASE: xfstest ext4/004

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-11 17:57:35 -05:00
Darrick J. Wong dc7b8dad99 libext2fs: file IO routines should handle uninit blocks
The file IO routines do not handle uninit blocks at all.  The read
method should check for the uninit flag and return a buffer of zeroes,
and the write routine should convert unwritten extents.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-02 22:57:14 -05:00
Darrick J. Wong 3548bb64b5 libext2fs: refactor extent head creation
Don't open-code the creation of the extent tree header, since
ext2fs_extent_open2() knows how to take care of this.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-02 22:55:04 -05:00
Darrick J. Wong 54f6faf7f2 libext2fs: don't report garbage inodes with really large inodes
If the inode size is large enough that there are fewer than two inodes
per block, don't report an inode checksum failure as a garbage inode
during the scan because the "more than half are broken" criteria that
we use to decide if a block of inodes is garbage doesn't really apply.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-02 22:17:10 -05:00
Theodore Ts'o bbf29ce6e9 Merge branch 'maint' into next 2014-12-02 22:15:25 -05:00
Darrick J. Wong c9d6c22ded libext2fs: don't allow alloc_stats on bad inode/block numbers
Don't allow callers to feed bad block/inode numbers to
ext2fs_*_alloc_stats2, because evil callers (<cough>resize2fs<cough>)
can corrupt library state this way, leading to a crash.

(There will be a subsequent patch to resize2fs to fix its bad
behavior.)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-17 17:59:42 -05:00
Darrick J. Wong c0ff3a21b6 libext2fs: set BLOCK_UNINIT for non-last blockgroups if all blocks are free
Set BLOCK_UNINIT in any group whose blocks are all unused, so long as
it isn't the last group.  This helps us speed up future e2fsck runs
and mounts because we don't need to read or checksum block bitmaps for
these groups.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-17 17:46:13 -05:00
Darrick J. Wong 407916f5af libext2fs: fix endian handling error; reduce fragmentation some
If we're going to read the "nr - 1" entry in an indirect block for use
as a "goal" input to the block allocator, we need to byteswap the
entry.  While we're at it, if we're allocating blocks for the zeroth
entry in the indirect block, we might as well use the indirect block
as the starting point to try to reduce fragmentation.

(d_fallocate_blkmap will test this...)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-07 21:27:53 -05:00
Darrick J. Wong 180f376b04 misc: fix compiler warnings and minor build errors
Fix some gcc-4.8 warnings and other problems that broke the build.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-07 21:23:41 -05:00
Darrick J. Wong 12406b37b2 libext2fs: fix endian checking bits
Commit 3e683eef93 ("define bitwise types and annotate conversion
routines") broke the build on various platforms.  Turns out that
crossing our fingers wasn't such a good idea, so just define it
separately.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-05 11:08:32 -05:00
Darrick J. Wong bab25cb7a7 libext2fs: zero the EA block buffer before filling it
When writing an extended attribute (EA) block, it's quite possible
that the EA formatting code will not write the entire buffer.
Therefore, we must zero the buffer beforehand to avoid writing random
heap contents to disk.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: Sami Liedes <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-04 11:47:30 -05:00
Theodore Ts'o dfa667dab6 Merge branch 'maint' into next
Conflicts:
	lib/ext2fs/dir_iterate.c
2014-11-04 11:46:55 -05:00
Darrick J. Wong 8d5324c43f libext2fs: don't memcpy identical pointers when writing a cache block
Sami Liedes found a scenario where we could memcpy incorrectly:

If a block read fails during an e2fsck run, the UNIX IO manager will
call the io->read_error routine with a pointer to the internal block
cache.  The e2fsck read error handler immediately tries to write the
buffer back out to disk(!), at which point the block write code will
try to copy the buffer contents back into the block cache.  Normally
this is fine, but not when the write buffer is the cache itself!

So, plumb in a trivial check for this condition.  A more thorough
solution would pass a duplicated buffer to the IO error handlers, but
I don't know if that happens frequently enough to be worth the extra
point of failure.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: Sami Liedes <sami.liedes@iki.fi>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-04 11:43:08 -05:00