Stop directly referencing b_bn in code outside the buffer cache, as
b_bn is supposed to be used only as an internal cache index.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
This is a conversion of the remaining xfs_sb_version_has..(sbp)
checks to use xfs_has_..(mp) feature checks.
This was largely done with a vim replacement macro that did:
:0,$s/xfs_sb_version_has\(.*\)&\(.*\)->m_sb/xfs_has_\1\2/g<CR>
A couple of other variants were also used, and the rest touched up
by hand.
$ size -t fs/xfs/built-in.a
text data bss dec hex filename
before 1127533 311352 484 1439369 15f689 (TOTALS)
after 1125360 311352 484 1437196 15ee0c (TOTALS)
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Convert the xfs_sb_version_hasfoo() to checks against
mp->m_features. Checks of the superblock itself during disk
operations (e.g. in the read/write verifiers and the to/from disk
formatters) are not converted - they operate purely on the
superblock state. Everything else should use the mount features.
Large parts of this conversion were done with sed with commands like
this:
for f in `git grep -l xfs_sb_version_has fs/xfs/*.c`; do
sed -i -e 's/xfs_sb_version_has\(.*\)(&\(.*\)->m_sb)/xfs_has_\1(\2)/' $f
done
With manual cleanups for things like "xfs_has_extflgbit" and other
little inconsistencies in naming.
The result is ia lot less typing to check features and an XFS binary
size reduced by a bit over 3kB:
$ size -t fs/xfs/built-in.a
text data bss dec hex filenam
before 1130866 311352 484 1442702 16038e (TOTALS)
after 1127727 311352 484 1439563 15f74b (TOTALS)
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
In preparation of removing the historic icinode struct, move the on-disk
size field into the containing xfs_inode structure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
On debug kernels, we call xfs_dir3_leaf_check_int() multiple times
on every directory modification. The robust hash ordering checks it
does on every entry in the leaf on every call results in a massive
CPU overhead which slows down debug kernels by a large amount.
We use xfs_dir3_leaf_check_int() for the verifiers as well, so we
can't just gut the function to reduce overhead. What we can do,
however, is reduce the work it does when it is called from the
debug interfaces, just leaving the high level checks in place and
leaving the robust validation to the verifiers. This means the debug
checks will catch gross errors, but subtle bugs might not be caught
until a verifier is run.
It is easy enough to restore the existing debug behaviour if the
developer needs it (just change a call parameter in the debug code),
but overwise the overhead makes testing large directory block sizes
on debug kernels very slow.
Profile at an unlink rate of ~80k file/s on a 64k block size
filesystem before the patch:
40.30% [kernel] [k] xfs_dir3_leaf_check_int
10.98% [kernel] [k] __xfs_dir3_data_check
8.10% [kernel] [k] xfs_verify_dir_ino
4.42% [kernel] [k] memcpy
2.22% [kernel] [k] xfs_dir2_data_get_ftype
1.52% [kernel] [k] do_raw_spin_lock
Profile after, at an unlink rate of ~125k files/s (+50% improvement)
has largely dropped the leaf verification debug overhead out of the
profile.
16.53% [kernel] [k] __xfs_dir3_data_check
12.53% [kernel] [k] xfs_verify_dir_ino
7.97% [kernel] [k] memcpy
3.36% [kernel] [k] xfs_dir2_data_get_ftype
2.86% [kernel] [k] __pv_queued_spin_lock_slowpath
Create shows a similar change in profile and a +25% improvement in
performance.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Add a helper function to get rid of buffers that we have decided are
corrupt after the verifiers have run. This function is intended to
handle metadata checks that can't happen in the verifiers, such as
inter-block relationship checking. Note that we now mark the buffer
stale so that it will not end up on any LRU and will be purged on
release.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Use the xfs_da_get_buf_daddr function directly for the two callers
that pass a mapped disk address, and then remove the mappedbno argument.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Move the code for reading an already mapped block into
xfs_da3_node_read_mapped, which is the only caller ever passing a block
number in the mappedbno argument and replace the mappedbno argument with
the simple xfs_dabuf_get flags.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This argument is always hard coded to -1, so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This argument is always hard coded to -1, so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Instead of causing a relatively expensive indirect call for each
hashing and comparism of a file name in a directory just use an
inline function and a simple branch on the ASCII CI bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: fix unused variable warning]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Move the code for extracting the incore header to the only caller that
didn't already do that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
There is no real need for xfs_dir2_data_freescan wrapper, so rename
xfs_dir2_data_freescan_int to xfs_dir2_data_freescan and let the
callers dereference the mount pointer from the inode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->data_get_ftype and ->data_put_ftype dir ops methods with
directly called xfs_dir2_data_get_ftype and xfs_dir2_data_put_ftype
helpers that takes care of the differences between the directory format
with and without the file type field.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->data_bestfree_p dir ops method with a directly called
xfs_dir2_data_bestfree_p helper that takes care of the differences
between the v4 and v5 on-disk format.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Move the data block fixed offsets towards our structure for dir/attr
geometry parameters.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->data_entry_tag_p dir ops method with a directly called
xfs_dir2_data_entry_tag_p helper that takes care of the differences
between the directory format with and without the file type field.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->data_entsize dir ops method with a directly called
xfs_dir2_data_entsize helper that takes care of the differences between
the directory format with and without the file type field.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
All but two callers of the ->free_bests_p dir operation already have a
struct xfs_dir3_icfree_hdr from a previous call to
xfs_dir2_free_hdr_from_disk at hand. Add a pointer to the bests to
struct xfs_dir3_icfree_hdr to clean up this pattern. To optimize this
pattern, pass the struct xfs_dir3_icfree_hdr to xfs_dir2_free_log_bests
instead of recalculating the pointer there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->free_hdr_from_disk dir ops method with a directly called
xfs_dir_free_hdr_from_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Move the max leaf entries count towards our structure for dir/attr
geometry parameters.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Move the leaf header size towards our structure for dir/attr geometry
parameters.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
All callers of the ->node_tree_p dir operation already have a struct
xfs_dir3_icleaf_hdr from a previous call to xfs_da_leaf_hdr_from_disk at
hand, or just need slight changes to the calling conventions to do so.
Add a pointer to the entries to struct xfs_dir3_icleaf_hdr to clean up
this pattern. To make this possible the xfs_dir3_leaf_log_ents function
grow a new argument to pass the xfs_dir3_icleaf_hdr that call callers
already have, and xfs_dir2_leaf_lookup_int returns the
xfs_dir3_icleaf_hdr to the callers so that they can later use it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->leaf_hdr_to_disk dir ops method with a directly called
xfs_dir_leaf_hdr_to_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Replace the ->leaf_hdr_from_disk dir ops method with a directly called
xfs_dir2_leaf_hdr_from_disk helper that takes care of the differences
between the v4 and v5 on-disk format.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Make sure we log something to dmesg whenever we return -EFSCORRUPTED up
the call stack.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
There are many, many xfs header files which are included but
unneeded (or included twice) in the xfs code, so remove them.
nb: xfs_linux.h includes about 9 headers for everyone, so those
explicit includes get removed by this. I'm not sure what the
preference is, but if we wanted explicit includes everywhere,
a followup patch could remove those xfs_*.h includes from
xfs_linux.h and move them into the files that need them.
Or it could be left as-is.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
We need to derive the mount pointer from a buffer in a lot of place.
Add a direct pointer to short cut the pointer chasing.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The inode geometry structure isn't related to ondisk format; it's
support for the mount structure. Move it to xfs_shared.h.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Remove typedefs and consolidate local variable initialization.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Smatch complains about the following:
fs/xfs/libxfs/xfs_dir2_leaf.c:848 xfs_dir2_leaf_addname() error:
uninitialized symbol 'lowstale'.
fs/xfs/libxfs/xfs_dir2_leaf.c:849 xfs_dir2_leaf_addname() error:
uninitialized symbol 'highstale'.
I don't think there's any incorrect behavior associated with the
uninitialized variable, but as the author of the previous zero-init
patch points out, it's best not to be passing around pointers to
uninitialized stack areas.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Create a separate magic16 check function so that we don't run afoul of
static checkers.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
With the verifier magic value helper in place, we've left a bit more
duplicate code across the verifiers that involve struct
xfs_da3_blkinfo. This includes the da node, xattr leaf and dir leaf
verifiers, all of which perform similar checks for v4 and v5
filesystems.
Create a common helper to verify an xfs_da3_blkinfo structure,
taking care to only access v5 fields where appropriate, and refactor
the aforementioned verifiers to use the helper. No functional
changes.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
The dir2 leaf verifiers share the same underlying structure
verification code, but implement six accessor functions to multiplex
the code across the two verifiers. Further, the magic value isn't
sufficiently abstracted such that the common helper has to manually
fix up the magic from the caller on v5 filesystems.
Use the magic field in the verifier structure to eliminate the
duplicate code and clean this all up. No functional change.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Get rid of the MIN/MAX macros and just use the native min/max macros
directly in the XFS code.
Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Remove the verbose license text from XFS files and replace them
with SPDX tags. This does not change the license of any of the code,
merely refers to the common, up-to-date license files in LICENSES/
This change was mostly scripted. fs/xfs/Makefile and
fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected
and modified by the following command:
for f in `git grep -l "GNU General" fs/xfs/` ; do
echo $f
cat $f | awk -f hdr.awk > $f.new
mv -f $f.new $f
done
And the hdr.awk script that did the modification (including
detecting the difference between GPL-2.0 and GPL-2.0+ licenses)
is as follows:
$ cat hdr.awk
BEGIN {
hdr = 1.0
tag = "GPL-2.0"
str = ""
}
/^ \* This program is free software/ {
hdr = 2.0;
next
}
/any later version./ {
tag = "GPL-2.0+"
next
}
/^ \*\// {
if (hdr > 0.0) {
print "// SPDX-License-Identifier: " tag
print str
print $0
str=""
hdr = 0.0
next
}
print $0
next
}
/^ \* / {
if (hdr > 1.0)
next
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
next
}
/^ \*/ {
if (hdr > 0.0)
next
print $0
next
}
// {
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
}
END { }
$
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Explicitly pass the buffer length to xfs_corruption_error() instead of
assuming XFS_CORRUPTION_DUMP_LEN so that we avoid dumping off the end
of the buffer.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In xfs_dir2_leaf_addname we ASSERT if the length of the unused space
described by bestfree[0] is less the amount of space we wish to consume.
Immediately after it is a call to xfs_dir2_data_use_free where the
offset parameter is offset of the unused space and the length parameter
is the amount of space we wish to consume. Both values (and the unused
space pointer) are passed into xfs_dir2_data_check_free, which also
validates that the region of unused space is big enough to cover the
space we wish to consume. This is effectively the same check that the
ASSERT covers, and since a check failure results in a corruption message
being logged we can remove the ASSERT.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In xfs_dir2_data_use_free, we examine on-disk metadata and ASSERT if
it doesn't make sense. Since a carefully crafted fuzzed image can cause
the kernel to crash after blowing a bunch of assertions, let's move
those checks into a validator function and rig everything up to return
EFSCORRUPTED to userspace. Found by lastbit fuzzing ltail.bestcount via
xfs/391.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Yet another round of playing whack-a-mole with directory code that
asserts on corrupt on-disk metadata when it really should be returning
-EFSCORRUPTED instead of ASSERTing. Found by a xfs/391 crash while
lastbit fuzzing of ltail.bestcount.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
By splitting the b_fspriv field into two different fields (b_log_item
and b_li_list). It's possible to get rid of an old ABI workaround, by
using the new b_log_item field to store xfs_buf_log_item separated from
the log items attached to the buffer, which will be linked in the new
b_li_list field.
This way, there is no more need to reorder the log items list to place
the buf_log_item at the beginning of the list, simplifying a bit the
logic to handle buffer IO.
This also opens the possibility to change buffer's log items list into a
proper list_head.
b_log_item field is still defined as a void *, because it is still used
by the log buffers to store xlog_in_core structures, and there is no
need to add an extra field on xfs_buf just for xlog_in_core.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: minor style changes]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Expose all metadata structure buffer verifier functions via buf_ops.
These will be used by the online scrub mechanism to look for problems
with buffers that are already sitting around in memory.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Refactor the callers of verifiers to print the instruction address of a
failing check.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Modify each function that checks the contents of a metadata buffer to
return the instruction address of the failing test so that we can report
more precise failure errors to the log.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Since all verification errors also mark the buffer as having an error,
we can combine these two calls. Later we'll add a xfs_failaddr_t
parameter to promote the idea of reporting corruption errors and the
address of the failing check to enable better debugging reports.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
In quite a few places we call xfs_da_read_buf with a mappedbno that we
don't control, then assume that the function passes back either an error
code or a buffer pointer. Unfortunately, if mappedbno == -2 and bno
maps to a hole, we get a return code of zero and a NULL buffer, which
means that we crash if we actually try to use that buffer pointer. This
happens immediately when we set the buffer type for transaction context.
Therefore, check that we have no error code and a non-NULL bp before
trying to use bp. This patch is a follow-up to an incomplete fix in
96a3aefb8f ("xfs: don't crash if reading a directory results in an
unexpected hole").
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Export various internal functions so that the online scrubber can use
them to check the state of metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
This is a purely mechanical patch that removes the private
__{u,}int{8,16,32,64}_t typedefs in favor of using the system
{u,}int{8,16,32,64}_t typedefs. This is the sed script used to perform
the transformation and fix the resulting whitespace and indentation
errors:
s/typedef\t__uint8_t/typedef __uint8_t\t/g
s/typedef\t__uint/typedef __uint/g
s/typedef\t__int\([0-9]*\)_t/typedef int\1_t\t/g
s/__uint8_t\t/__uint8_t\t\t/g
s/__uint/uint/g
s/__int\([0-9]*\)_t\t/__int\1_t\t\t/g
s/__int/int/g
/^typedef.*int[0-9]*_t;$/d
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This adds a name to each buf_ops structure, so that if
a verifier fails we can print the type of verifier that
failed it. Should be a slight debugging aid, I hope.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Since the onset of v5 superblocks, the LSN of the last modification has
been included in a variety of on-disk data structures. This LSN is used
to provide log recovery ordering guarantees (e.g., to ensure an older
log recovery item is not replayed over a newer target data structure).
While this works correctly from the point a filesystem is formatted and
mounted, userspace tools have some problematic behaviors that defeat
this mechanism. For example, xfs_repair historically zeroes out the log
unconditionally (regardless of whether corruption is detected). If this
occurs, the LSN of the filesystem is reset and the log is now in a
problematic state with respect to on-disk metadata structures that might
have a larger LSN. Until either the log catches up to the highest
previously used metadata LSN or each affected data structure is modified
and written out without incident (which resets the metadata LSN), log
recovery is susceptible to filesystem corruption.
This problem is ultimately addressed and repaired in the associated
userspace tools. The kernel is still responsible to detect the problem
and notify the user that something is wrong. Check the superblock LSN at
mount time and fail the mount if it is invalid. From that point on,
trigger verifier failure on any metadata I/O where an invalid LSN is
detected. This results in a filesystem shutdown and guarantees that we
do not log metadata changes with invalid LSNs on disk. Since this is a
known issue with a known recovery path, present a warning to instruct
the user how to recover.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Dave Chinner