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>
In practice, it is **extremely** rare for users to try to use more
than the first backup superblock located at the beginning of block
group #1. (i.e., at block number 32768 for file systems with a 4k
block size). This new compat feature restricts the backup superblock
to block group #1 and the last block group in the file system.
Aside from reducing the overhead of the file system by a small number
of blocks, by eliminating the rest of the backup superblocks, it
allows us to have a much more flexible metadata layout. For example,
we can force all of the allocation bitmaps and inode table blocks to
the beginning of the disk, which allows most of the disk to be
exclusively used for contiguous data blocks.
This simplifies taking advantage of certain HDD specific features,
such as Shingled Magnetic Recording (aka Shingled Drives), and the
TCG's OPAL Storage Specification where having a simple mapping between
LBA block ranges and the data blocks used by the file system can make
life much simpler.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Since clang uses C99 semantics by default, the main changes required
to allow clang to build e2fsprogs was to add support the C99 inline
semantics, while still allowing us to be built when the legacy (but
still default for gcc) GNU C89 inline semantics are in force.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Define flags and extend ext4 structure definitions to support metadata
checksumming. Ted Ts'o covered many of these fields in an earlier
patch, but there are more required changes to the disk layout.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In addition to validating the ordering of fields within the inode
and superblock structures, also validate the field sizes. Otherwise
it is possible to incorrectly change the size of one of these fields
without getting any kind of error from these tests. Failures would
only show up later in the test image checks if the field that is
changed is before another in-use field.
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Multi-mount protection is feature that allows mke2fs, e2fsck, and
others to detect if the filesystem is mounted on a remote node (on
SAN disks) and avoid corrupting the filesystem. For e2fsprogs this
means that it checks the MMP block to see if the filesystem is in use,
and marks the filesystem busy while e2fsck is running on the system.
This is useful on SAN disks that are shared between high-availability
servers, or accessible by multiple nodes that aren't in HA pairs. MMP
isn't intended to serve as a primary HA exclusion mechanism, but as a
failsafe to protect against user, software, or hardware errors.
There is no requirement that e2fsck updates the MMP block at regular
intervals, but e2fsck does this occasionally to provide useful
information to the sysadmin in case of a detected conflict.
For the kernel (since Linux 3.0) MMP adds a "heartbeat" mechanism to
periodically write to disk (every few seconds by default) to notify
other nodes that the filesystem is still in use and unsafe to modify.
Originally-by: Kalpak Shah <kalpak@clusterfs.com>
Signed-off-by: Johann Lombardi <johann@whamcloud.com>
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The DEFS line in MCONFIG had gotten so long that it exceeded 4k, and
this was starting to cause some tools heartburn. It also made "make
V=1" almost useless, since trying to following the individual commands
run by make was lost in the noise of all of the defines.
So fix this by putting the configure-generated defines in lib/config.h
and the directory pathnames to lib/dirpaths.h.
In addition, clean up some vestigal defines in configure.in and in the
Makefiles to further shorten the cc command lines.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The set_fields commands (set_super_value, set_inode_field,
set_block_group) now handle fields which store in split fields on
ext4's on-disk format. For example, the superblock fields
s_blocks_count and s_blocks_count_hi.
The user can either set the low or high part of the field via
"blocks_count_lo" or "blocks_count_hi", or both parts can be set via
"blocks_count".
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reserve EXT4_FEATURE_RO_COMPAT_METADATA_CSUM and
EXT2_FEATURE_COMPAT_EXCLUDE_BITMAP. Also reserve fields in the
superblock and the inode for the checksums. In the block group
descriptor, reserve the exclude bitmap field for the snapshot feature,
and checksums for the inode and block allocation bitmaps.
With this commit, the metadata checksum and exclude bitmap features
should have reserved all of the fields they need in ext4's on-disk
format.
This commit also fixes an a missing byte swap for s_overhead_blocks.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Amir Goldstein <amir73il@gmail.com>
It turns out that it's very hard to calculate overheads in the face of
clustered allocation (bigalloc). This is because multiple metadata
blocks from different block groups can end up in the same allocation
cluster. Calculating the exact overhead requires O(all block bitmaps)
in memory, or O(number of block groups**2) in time. So we will
calculate this at mkfs time and stash it in the superblock.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This adds the superblock fields needed so that dumpe2fs works and the
code points and renames the superblock fields from describing
fragments to clusters.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch adds support for detecting the new 'quota' feature in ext4.
The patch reserves code points for usr and group quota inodes and also
for the feature flag EXT4_FEATURE_RO_COMPAT_QUOTA.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The test now checks to make sure the superblock fields are correctly
aligned and prints them out so they can be manually checked to make
sure they are where we expect them to be.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The top-level COPYING file states that the e2p and ext2fs libraries
are available under the LGPLv2. The files were incorrectly labelled.
Alex Thomas/Luster has been consulted wrt to the ext3_extents.h file;
the rest of the files were primarily authored by Theodore Ts'o.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Theodore Ts'o