xfs: move symlink target write function to libxfs

Move xfs_symlink_write_target to xfs_symlink_remote.c so that kernel and
mkfs can share the same function.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

xfs: move remote symlink target read function to libxfs

Move xfs_readlink_bmap_ilocked to xfs_symlink_remote.c so that the
swapext code can use it to convert a remote format symlink back to
shortform format after a metadata repair. While we're at it, fix a
broken printf prefix.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

xfs: move xfs_symlink_remote.c declarations to xfs_symlink_remote.h

Move declarations for libxfs symlink functions into a separate header
file like we do for most everything else.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

xfs: make if_data a void pointer

The xfs_ifork structure currently has a union of the if_root void pointer
and the if_data char pointer. In either case it is an opaque pointer
that depends on the fork format. Replace the union with a single if_data
void pointer as that is what almost all callers want. Only the symlink
NULL termination code in xfs_init_local_fork actually needs a new local
variable now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

xfs: zap broken inode forks

Determine if inode fork damage is responsible for the inode being unable
to pass the ifork verifiers in xfs_iget and zap the fork contents if
this is true. Once this is done the fork will be empty but we'll be
able to construct an in-core inode, and a subsequent call to the inode
fork repair ioctl will search the rmapbt to rebuild the records that
were in the fork.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

xfs: convert XFS_IFORK_PTR to a static inline helper

We're about to make this logic do a bit more, so convert the macro to a
static inline function for better typechecking and fewer shouty macros.
No functional changes here.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: fix typo in comment

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: convert bp->b_bn references to xfs_buf_daddr()

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>

xfs: replace xfs_sb_version checks with feature flag checks

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>

xfs: move the fork format fields into struct xfs_ifork

Both the data and attr fork have a format that is stored in the legacy
idinode. Move it into the xfs_ifork structure instead, where it uses
up padding.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

xfs: remove unused header files

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>

xfs: add struct xfs_mount pointer to struct xfs_buf

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>

xfs: miscellaneous verifier magic value fixups

Most buffer verifiers have hardcoded magic value checks
conditionalized on the version of the filesystem. The magic value
field of the verifier structure facilitates abstraction of some of
this code. Populate the ->magic field of various verifiers to take
advantage of this abstraction. 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>

xfs: zero length symlinks are not valid

A log recovery failure has been reproduced where a symlink inode has
a zero length in extent form. It was caused by a shutdown during a
combined fstress+fsmark workload.

The underlying problem is the issue in xfs_inactive_symlink(): the
inode is unlocked between the symlink inactivation/truncation and
the inode being freed. This opens a window for the inode to be
written to disk before it xfs_ifree() removes it from the unlinked
list, marks it free in the inobt and zeros the mode.

For shortform inodes, the fix is simple. xfs_ifree() clears the data
fork state, so there's no need to do it in xfs_inactive_symlink().
This means the shortform fork verifier will not see a zero length
data fork as it mirrors the inode size through to xfs_ifree()), and
hence if the inode gets written back and the fork verifiers are run
they will still see a fork that matches the on-disk inode size.

For extent form (remote) symlinks, it is a little more tricky. Here
we explicitly set the inode size to zero, so the above race can lead
to zero length symlinks on disk. Because the inode is unlinked at
this point (i.e. on the unlinked list) and unreferenced, it can
never be seen again by a user. Hence when we set the inode size to
zeor, also change the type to S_IFREG. xfs_ifree() expects S_IFREG
inodes to be of zero length, and so this avoids all the problems of
zero length symlinks ever hitting the disk. It also avoids the
problem of needing to handle zero length symlink inodes in log
recovery to replay the extent free intents and the remaining
deferops to free the extents the symlink used.

Also add a couple of asserts to warn us if zero length symlinks end
up in either the symlink create or inactivation paths.

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>

xfs: convert to SPDX license tags

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>

Split buffer's b_fspriv field

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>

xfs: create a new buf_ops pointer to verify structure metadata

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>

xfs: create structure verifier function for short form symlinks

Create a function to check the structure of short form symlink targets.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: refactor verifier callers to print address of failing check

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>

xfs: have buffer verifier functions report failing address

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>

xfs: refactor xfs_verifier_error and xfs_buf_ioerror

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>

xfs: rename MAXPATHLEN to XFS_SYMLINK_MAXLEN

XFS has a maximum symlink target length of 1024 bytes; this is a
holdover from the Irix days. Unfortunately, the constant establishing
this is 'MAXPATHLEN' and is /not/ the same as the Linux MAXPATHLEN,
which is 4096.

The kernel enforces its 1024 byte MAXPATHLEN on symlink targets, but
xfsprogs picks up the (Linux) system 4096 byte MAXPATHLEN, which means
that xfs_repair doesn't complain about oversized symlinks.

Since this is an on-disk format constraint, put the define in the XFS
namespace and move everything over to use the new name.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

xfs: print name of verifier if it fails

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>

xfs: validate metadata LSNs against log on v5 superblocks

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>

xfs: log local to remote symlink conversions correctly on v5 supers

A local format symlink inode is converted to extent format when an
extended attribute is set on an inode as part of the attribute fork
creation. This means a block is allocated, the local symlink target name
is copied to the block and the block is logged. Currently,
xfs_bmap_local_to_extents() handles logging the remote block data based
on the size of the data fork prior to the conversion. This is not
correct on v5 superblock filesystems, which add an additional header to
remote symlink blocks that is nonexistent in local format inodes.

As a result, the full length of the remote symlink block content is not
logged. This can lead to corruption should a crash occur and log
recovery replay this transaction.

Since a callout is already used to initialize the new remote symlink
block, update the local-to-extents conversion mechanism to make the
callout also responsible for logging the block. It is already required
to set the log buffer type and format the block appropriately based on
the superblock version. This ensures the remote symlink is always logged
correctly. Note that xfs_bmap_local_to_extents() is only called for
symlinks so there are no other callouts that require modification.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: create new metadata UUID field and incompat flag

This adds a new superblock field, sb_meta_uuid. If set, along with
a new incompat flag, the code will use that field on a V5 filesystem
to compare to metadata UUIDs, which allows us to change the user-
visible UUID at will. Userspace handles the setting and clearing
of the incompat flag as appropriate, as the UUID gets changed; i.e.
setting the user-visible UUID back to the original UUID (as stored in
the new field) will remove the incompatible feature flag.

If the incompat flag is not set, this copies the user-visible UUID into
into the meta_uuid slot in memory when the superblock is read from disk;
the meta_uuid field is not written back to disk in this case.

The remainder of this patch simply switches verifiers, initializers,
etc to use the new sb_meta_uuid field.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: set buf types when converting extent formats

Conversion from local to extent format does not set the buffer type
correctly on the new extent buffer when a symlink data is moved out
of line.

Fix the symlink code and leave a comment in the generic bmap code
reminding us that the format-specific data copy needs to set the
destination buffer type appropriately.

cc: <stable@vger.kernel.org> # 3.10 to current
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: move most of xfs_sb.h to xfs_format.h

More on-disk format consolidation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: merge xfs_ag.h into xfs_format.h

More on-disk format consolidation. A few declarations that weren't on-disk
format related move into better suitable spots.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: global error sign conversion

Convert all the errors the core XFs code to negative error signs
like the rest of the kernel and remove all the sign conversion we
do in the interface layers.

Errors for conversion (and comparison) found via searches like:

$ git grep " E" fs/xfs
$ git grep "return E" fs/xfs
$ git grep " E[A-Z].*;$" fs/xfs

Negation points found via searches like:

$ git grep "= -[a-z,A-Z]" fs/xfs
$ git grep "return -[a-z,A-D,F-Z]" fs/xfs
$ git grep " -[a-z].*;" fs/xfs

[ with some bits I missed from Brian Foster ]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

libxfs: move source files

Move all the source files that are shared with userspace into
libxfs/. This is done as one big chunk simpy to get it done
quickly

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>