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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Theodore Ts'o