This new manager is similar to the unix_io_manager except it takes a
file descriptor as first argument instead of a filename.
Some programs may want libext2fs to directly use a fd instead of
letting it opening the file.
The use case for such a io_manager would be to let programs use
a fd even if the filename is unknown:
- the fd comes from a temporary file (O_TMPFILE);
- the fd comes from a unix socket...
Refactoring unix_open() also fix a bug when the IO_DIRECT flag was
specified: ext2fs_get_dio_alignment() was called before the file was
actually opened, resulting in an alignment of 0.
Signed-off-by: Adrien Schildknecht <adriens@google.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>
Add a readahead method for prefetching ranges of disk blocks. This is
useful for inode table scanning, and other large contiguous ranges of
blocks, and may also prove useful for random block prefetch, since it
will allow reordering of the IO without waiting synchronously for the
reads to complete.
It is currently using the posix_fadvise(POSIX_FADV_WILLNEED)
interface, as this proved most efficient during our testing.
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Create a new function, io_channel_alloc_buf() which allocates I/O
buffers with appropriate alignment if we are using direct I/O. The
original code was sometimes using a larger alignment factor than
necessary, and would always request an aligned memory buffer even when
it was not necessary since the block device was not opened with
O_DIRECT.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The align field which indicated the required data alignment of data
buffers was stored in a field specific to the unix_io manager. Move
it to the top-level io_channel structure so it can be better
generalized.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
If e2fsprogs tools (mke2fs, e2fsck) is run on regular file instead of
on block device, we can use punch hole instead of regular discard
command which would not work on regular file anyway. This gives us
several advantages. First of all when e2fsck is run with '-E discard'
parameter it will punch out all ununsed space from the image, hence
trimming down the file system image. And secondly, when creating an
file system on regular file (with '-E discard' which is default), we
can use punch hole to clear the file content, hence we can skip inode
table initialization, because reads from sparse area returns zeros. This
will result in faster file system creation (without the need to specify
lazy_itable_init) and smaller images.
This commit also fixes some tests that would fail due to mke2fs showing
discard progress, hence the output would differ.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Check to see if the device supports discard before starting the
progress bar, and then printing an error about inappropriate ioctl for
device (when creating a file system image to a file, for example).
Also, add a function signature in the ext2_io.h header file for
io_channel_discard() and fix an extra, uneeded argument in mke2fs's
call to that function.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When the device have discard support and simultaneously discard zeroes
data (and it is properly advertised), then we can take advantage of such
behavior in several e2fsprogs tools.
Add new flag CHANNEL_FLAGS_DISCARD_ZEROES for struct_io_channel so
each io_manager can take advantage of this. The flag is properly set
according to BLKDISCARDZEROES ioctl in unix_open.
Also remove old mke2fs_discard_zeroes_data() function and substitute it
with helper which test this flag.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In order to provide generic "discard" function for all e2fsprogs tools
add a discard function prototype into struct_io_manager. Specific
function for specific io managers can be crated that way.
This commit also creates unix_discard function which uses BLKDISCARD
ioctl to discard data blocks on the block device and bind it into
unit_io_manager structure to be available for all e2fsprogs tools.
Note that BLKDISCARD is still Linux specific ioctl, however other
unix systems may provide similar functionality. So far the
unix_discard() remains linux specific hence is embedded in #ifdef
__linux__ macro.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This adds the basic support for Direct I/O to unix_io.c, and adds a
new flag EXT_FLAG_DIRECT_IO which can be passed to ext2fs_open() or
ext2fs_open2() to request Direct I/O support.
Note that device mapper devices in Linux don't support Direct I/O, and
in some circumstances using Direct I/O can actually make performance
*worse*!
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>
Provide a C language wrapper function for io_channel_read_blk64() and
io_channel_write_blk64() instead of using a C preprocessor macro, with
an fallback to the old 32-bit functions if an application-provided I/O
channel manager doesn't supply 64-bit method functions and the block
numbers can fit in 32-bit integer.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This I/O manager saves the contents of the location being overwritten
to a tdb database. This helps in undoing the changes done to the
file system.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In order to provide 64-bit block support for IO managers an maintain
ABI compatibility with the old API, some new functions need to be
added to struct_io_manger. Luckily, strcut_io_manager has some
reserved space that we can use to add these new functions.
Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch instruments the libext2fs unix I/O manager and adds bytes
read/written and data rate to e2fsck -tt pass/overall timing output.
Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add a new io_channel open flag, IO_FLAG_EXCLUSIVE,which requests that
the device be opened in exclusive (O_EXCL) mode. Add support to the unix_io
implementation for this flag.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
example, /tmp/test.img?offset=1024. Multiple options can separated using
the & character, although at the moment the only option implemented is
the offset option in the unix_io layer.
ext2_io.h (io_channel_write_byte): Add new interface to allow callers
to write specific byte ranges. This is an optional interface, which
not all IO channels may implement.
unix_io.c (unix_write_byte): test_io.c (test_write_byte): Add
implementation of the write_byte function.
closefs.c (write_primary_superblock, ext2fs_flush): Add a new function
which writes the primary superblock. If the IO channel supports
writing raw bytes directly, only fields which were modified are
written to the disk. This makes it safe(r) to use utilities like
tune2fs on a mounted filesystem.
freefs.c (ext2fs_free): Free the original superblock if it is available.
openfs.c (ext2fs_open): Store a copy of the original superblock when
opening it.
ext2fs.h: Add a field to store the original superblock in the ext2
context structure.
ext2_io.h, ext2fs.h: Protect against being included multiple times.
bmove.c: #include ext2fsP.h instead of "ext2fs/ext2fs.h"
test_io.c (test_flush): Add a debugging printf when the flush method
is called.
rw_bitmaps.c (ext2fs_read_bitmaps): If the bitmaps are already read
in, return right away.
Vitaliy Filippov
Adrien Schildknecht