Commit Graph

92 Commits

Author SHA1 Message Date
Eric Sandeen ce5028cfe3 xfs: modify verifiers to differentiate CRC from other errors
Modify all read & write verifiers to differentiate
between CRC errors and other inconsistencies.

This sets the appropriate error number on bp->b_error,
and then calls xfs_verifier_error() if something went
wrong.  That function will issue the appropriate message
to the user.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:23:10 +11:00
Eric Sandeen f1dbcd7e38 xfs: add helper for updating checksums on xfs_bufs
Many/most callers of xfs_update_cksum() pass bp->b_addr and
BBTOB(bp->b_length) as the first 2 args.  Add a helper
which can just accept the bp and the crc offset, and work
it out on its own, for brevity.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:18:23 +11:00
Eric Sandeen 5158217058 xfs: add helper for verifying checksums on xfs_bufs
Many/most callers of xfs_verify_cksum() pass bp->b_addr and
BBTOB(bp->b_length) as the first 2 args.  Add a helper
which can just accept the bp and the crc offset, and work
it out on its own, for brevity.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-02-27 15:17:27 +11:00
Dave Chinner 632b89e82b xfs: fix static and extern sparse warnings
The kbuild test robot indicated that there were some new sparse
warnings in fs/xfs/xfs_dquot_buf.c. Actually, there were a lot more
that is wasn't warning about, so fix them all up.

Reported-by: kbuild test robot
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-30 13:59:56 -05:00
Dave Chinner 01ba43b873 xfs: vectorise encoding/decoding directory headers
Conversion from on-disk structures to in-core header structures
currently relies on magic number checks. If the magic number is
wrong, but one of the supported values, we do the wrong thing with
the encode/decode operation. Split these functions so that there are
discrete operations for the specific directory format we are
handling.

In doing this, move all the header encode/decode functions to
xfs_da_format.c as they are directly manipulating the on-disk
format. It should be noted that all the growth in binary size is
from xfs_da_format.c - the rest of the code actaully shrinks.

   text    data     bss     dec     hex filename
 794490   96802    1096  892388   d9de4 fs/xfs/xfs.o.orig
 792986   96802    1096  890884   d9804 fs/xfs/xfs.o.p1
 792350   96802    1096  890248   d9588 fs/xfs/xfs.o.p2
 789293   96802    1096  887191   d8997 fs/xfs/xfs.o.p3
 789005   96802    1096  886903   d8997 fs/xfs/xfs.o.p4
 789061   96802    1096  886959   d88af fs/xfs/xfs.o.p5
 789733   96802    1096  887631   d8b4f fs/xfs/xfs.o.p6
 791421   96802    1096  889319   d91e7 fs/xfs/xfs.o.p7

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-30 13:47:22 -05:00
Dave Chinner 4bceb18f15 xfs: vectorise DA btree operations
The remaining non-vectorised code for the directory structure is the
node format blocks. This is shared with the attribute tree, and so
is slightly more complex to vectorise.

Introduce a "non-directory" directory ops structure that is attached
to all non-directory inodes so that attribute operations can be
vectorised for all inodes.

Once we do this, we can vectorise all the da btree operations.
Because this patch adds more infrastructure than it removes the
binary size does not decrease:

   text    data     bss     dec     hex filename
 794490   96802    1096  892388   d9de4 fs/xfs/xfs.o.orig
 792986   96802    1096  890884   d9804 fs/xfs/xfs.o.p1
 792350   96802    1096  890248   d9588 fs/xfs/xfs.o.p2
 789293   96802    1096  887191   d8997 fs/xfs/xfs.o.p3
 789005   96802    1096  886903   d8997 fs/xfs/xfs.o.p4
 789061   96802    1096  886959   d88af fs/xfs/xfs.o.p5
 789733   96802    1096  887631   d8b4f fs/xfs/xfs.o.p6

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-30 13:43:28 -05:00
Dave Chinner a4fbe6ab1e xfs: decouple inode and bmap btree header files
Currently the xfs_inode.h header has a dependency on the definition
of the BMAP btree records as the inode fork includes an array of
xfs_bmbt_rec_host_t objects in it's definition.

Move all the btree format definitions from xfs_btree.h,
xfs_bmap_btree.h, xfs_alloc_btree.h and xfs_ialloc_btree.h to
xfs_format.h to continue the process of centralising the on-disk
format definitions. With this done, the xfs inode definitions are no
longer dependent on btree header files.

The enables a massive culling of unnecessary includes, with close to
200 #include directives removed from the XFS kernel code base.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-23 16:28:49 -05:00
Dave Chinner 239880ef64 xfs: decouple log and transaction headers
xfs_trans.h has a dependency on xfs_log.h for a couple of
structures. Most code that does transactions doesn't need to know
anything about the log, but this dependency means that they have to
include xfs_log.h. Decouple the xfs_trans.h and xfs_log.h header
files and clean up the includes to be in dependency order.

In doing this, remove the direct include of xfs_trans_reserve.h from
xfs_trans.h so that we remove the dependency between xfs_trans.h and
xfs_mount.h. Hence the xfs_trans.h include can be moved to the
indicate the actual dependencies other header files have on it.

Note that these are kernel only header files, so this does not
translate to any userspace changes at all.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-23 16:17:44 -05:00
Dave Chinner 5706278758 xfs: unify directory/attribute format definitions
The on-disk format definitions for the directory and attribute
structures are spread across 3 header files right now, only one of
which is dedicated to defining on-disk structures and their
manipulation (xfs_dir2_format.h). Pull all the format definitions
into a single header file - xfs_da_format.h - and switch all the
code over to point at that.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-10-23 14:21:40 -05:00
Eric Sandeen 914ed44b17 Fix wrong flag ASSERT in xfs_attr_shortform_getvalue
This ASSERT is testing an if_flags flag value against
a di_aformat enum value.  di_aformat is never assigned
XFS_IFINLINE.

This happens to work for now, because XFS_IFINLINE has
the same value as XFS_DINODE_FMT_LOCAL, and that's tested
just before we call this function.

However, I think the intention is to assert that we have
read in the data, i.e. XFS_IFINLINE on if_flags, before
we use if_data.  This is done in other places through the
code as well.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-30 15:20:50 -05:00
Dave Chinner c5c249b424 xfs: minor cleanups
These come from syncing the shared userspace and kernel code. Small
whitespace and trivial cleanups.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12 16:46:08 -05:00
Dave Chinner fde2227ce1 xfs: split out attribute fork truncation code into separate file
The attribute inactivation code is not used by userspace, so like
the attribute listing, split it out into a separate file to minimise
the differences between the filesystem shared with libxfs in
userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12 16:42:30 -05:00
Dave Chinner abec5f2bf9 xfs: split out attribute listing code into separate file
The attribute listing code is not used by userspace, so like the
directory readdir code, split it out into a separate file to
minimise the differences between the filesystem shared with libxfs
in userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12 16:41:29 -05:00
Dave Chinner d386b32b55 xfs: sync minor header differences needed by userspace.
Little things like exported functions, __KERNEL__ protections, and
so on that ensure user and kernel shared headers are identical.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12 16:35:41 -05:00
Dave Chinner f3508bcddf xfs: remove local fork format handling from xfs_bmapi_write()
The conversion from local format to extent format requires
interpretation of the data in the fork being converted, so it cannot
be done in a generic way. It is up to the caller to convert the fork
format to extent format before calling into xfs_bmapi_write() so
format conversion can be done correctly.

The code in xfs_bmapi_write() to convert the format is used
implicitly by the attribute and directory code, but they
specifically zero the fork size so that the conversion does not do
any allocation or manipulation. Move this conversion into the
shortform to leaf functions for the dir/attr code so the conversions
are explicitly controlled by all callers.

Now we can remove the conversion code in xfs_bmapi_write.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-07-09 16:40:22 -05:00
Dave Chinner 59913f14df xfs: fix remote attribute invalidation for a leaf
When invalidating an attribute leaf block block, there might be
remote attributes that it points to. With the recent rework of the
remote attribute format, we have to make sure we calculate the
length of the attribute correctly. We aren't doing that in
xfs_attr3_leaf_inactive(), so fix it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinuguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-04 17:36:30 -05:00
Dave Chinner ad1858d777 xfs: rework remote attr CRCs
Note: this changes the on-disk remote attribute format. I assert
that this is OK to do as CRCs are marked experimental and the first
kernel it is included in has not yet reached release yet. Further,
the userspace utilities are still evolving and so anyone using this
stuff right now is a developer or tester using volatile filesystems
for testing this feature. Hence changing the format right now to
save longer term pain is the right thing to do.

The fundamental change is to move from a header per extent in the
attribute to a header per filesytem block in the attribute. This
means there are more header blocks and the parsing of the attribute
data is slightly more complex, but it has the advantage that we
always know the size of the attribute on disk based on the length of
the data it contains.

This is where the header-per-extent method has problems. We don't
know the size of the attribute on disk without first knowing how
many extents are used to hold it. And we can't tell from a
mapping lookup, either, because remote attributes can be allocated
contiguously with other attribute blocks and so there is no obvious
way of determining the actual size of the atribute on disk short of
walking and mapping buffers.

The problem with this approach is that if we map a buffer
incorrectly (e.g. we make the last buffer for the attribute data too
long), we then get buffer cache lookup failure when we map it
correctly. i.e. we get a size mismatch on lookup. This is not
necessarily fatal, but it's a cache coherency problem that can lead
to returning the wrong data to userspace or writing the wrong data
to disk. And debug kernels will assert fail if this occurs.

I found lots of niggly little problems trying to fix this issue on a
4k block size filesystem, finally getting it to pass with lots of
fixes. The thing is, 1024 byte filesystems still failed, and it was
getting really complex handling all the corner cases that were
showing up. And there were clearly more that I hadn't found yet.

It is complex, fragile code, and if we don't fix it now, it will be
complex, fragile code forever more.

Hence the simple fix is to add a header to each filesystem block.
This gives us the same relationship between the attribute data
length and the number of blocks on disk as we have without CRCs -
it's a linear mapping and doesn't require us to guess anything. It
is simple to implement, too - the remote block count calculated at
lookup time can be used by the remote attribute set/get/remove code
without modification for both CRC and non-CRC filesystems. The world
becomes sane again.

Because the copy-in and copy-out now need to iterate over each
filesystem block, I moved them into helper functions so we separate
the block mapping and buffer manupulations from the attribute data
and CRC header manipulations. The code becomes much clearer as a
result, and it is a lot easier to understand and debug. It also
appears to be much more robust - once it worked on 4k block size
filesystems, it has worked without failure on 1k block size
filesystems, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-23 18:04:06 -05:00
Dave Chinner d4c712bcf2 xfs: fully initialise temp leaf in xfs_attr3_leaf_compact
xfs_attr3_leaf_compact() uses a temporary buffer for compacting the
the entries in a leaf. It copies the the original buffer into the
temporary buffer, then zeros the original buffer completely. It then
copies the entries back into the original buffer.  However, the
original buffer has not been correctly initialised, and so the
movement of the entries goes horribly wrong.

Make sure the zeroed destination buffer is fully initialised, and
once we've set up the destination incore header appropriately, write
is back to the buffer before starting to move entries around.

While debugging this, the _d/_s prefixes weren't sufficient to
remind me what buffer was what, so rename then all _src/_dst.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-23 17:53:08 -05:00
Dave Chinner 8517de2a81 xfs: fully initialise temp leaf in xfs_attr3_leaf_unbalance
xfs_attr3_leaf_unbalance() uses a temporary buffer for recombining
the entries in two leaves when the destination leaf requires
compaction. The temporary buffer ends up being copied back over the
original destination buffer, so the header in the temporary buffer
needs to contain all the information that is in the destination
buffer.

To make sure the temporary buffer is fully initialised, once we've
set up the temporary incore header appropriately, write is back to
the temporary buffer before starting to move entries around.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-23 17:52:07 -05:00
Dave Chinner e461fcb194 xfs: remote attribute lookups require the value length
When reading a remote attribute, to correctly calculate the length
of the data buffer for CRC enable filesystems, we need to know the
length of the attribute data. We get this information when we look
up the attribute, but we don't store it in the args structure along
with the other remote attr information we get from the lookup. Add
this information to the args structure so we can use it
appropriately.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-20 17:16:12 -05:00
Dave Chinner b38958d715 xfs: xfs_attr_shortform_allfit() does not handle attr3 format.
xfstests generic/117 fails with:

XFS: Assertion failed: leaf->hdr.info.magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC)

indicating a function that does not handle the attr3 format
correctly. Fix it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-20 16:53:22 -05:00
Dave Chinner 61fe135c1d xfs: buffer type overruns blf_flags field
The buffer type passed to log recvoery in the buffer log item
overruns the blf_flags field. I had assumed that flags field was a
32 bit value, and it turns out it is a unisgned short. Therefore
having 19 flags doesn't really work.

Convert the buffer type field to numeric value, and use the top 5
bits of the flags field for it. We currently have 17 types of
buffers, so using 5 bits gives us plenty of room for expansion in
future....

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 13:01:58 -05:00
Dave Chinner d75afeb3d3 xfs: add buffer types to directory and attribute buffers
Add buffer types to the buffer log items so that log recovery can
validate the buffers and calculate CRCs correctly after the buffers
are recovered.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 13:01:06 -05:00
Dave Chinner 95920cd6ce xfs: split remote attribute code out
Adding CRC support to remote attributes adds a significant amount of
remote attribute specific code. Split the existing remote attribute
code out into it's own file so that all the relevant remote
attribute code is in a single, easy to find place.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 12:49:32 -05:00
Dave Chinner 517c22207b xfs: add CRCs to attr leaf blocks
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 12:45:01 -05:00
Dave Chinner f5ea110044 xfs: add CRCs to dir2/da node blocks
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 12:33:38 -05:00
Christoph Hellwig ee1a47ab0e xfs: add support for large btree blocks
Add support for larger btree blocks that contains a CRC32C checksum,
a filesystem uuid and block number for detecting filesystem
consistency and out of place writes.

[dchinner@redhat.com] Also include an owner field to allow reverse
mappings to be implemented for improved repairability and a LSN
field to so that log recovery can easily determine the last
modification that made it to disk for each buffer.

[dchinner@redhat.com] Add buffer log format flags to indicate the
type of buffer to recovery so that we don't have to do blind magic
number tests to determine what the buffer is.

[dchinner@redhat.com] Modified to fit into the verifier structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21 14:53:46 -05:00
Christoph Hellwig 56cea2d088 xfs: take inode version into account in XFS_LITINO
Add a version argument to XFS_LITINO so that it can return different values
depending on the inode version.  This is required for the upcoming v3 inodes
with a larger fixed layout dinode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-03-14 16:19:14 -05:00
Dave Chinner 1813dd6405 xfs: convert buffer verifiers to an ops structure.
To separate the verifiers from iodone functions and associate read
and write verifiers at the same time, introduce a buffer verifier
operations structure to the xfs_buf.

This avoids the need for assigning the write verifier, clearing the
iodone function and re-running ioend processing in the read
verifier, and gets rid of the nasty "b_pre_io" name for the write
verifier function pointer. If we ever need to, it will also be
easier to add further content specific callbacks to a buffer with an
ops structure in place.

We also avoid needing to export verifier functions, instead we
can simply export the ops structures for those that are needed
outside the function they are defined in.

This patch also fixes a directory block readahead verifier issue
it exposed.

This patch also adds ops callbacks to the inode/alloc btree blocks
initialised by growfs. These will need more work before they will
work with CRCs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:35:12 -06:00
Dave Chinner b0f539de9f xfs: connect up write verifiers to new buffers
Metadata buffers that are read from disk have write verifiers
already attached to them, but newly allocated buffers do not. Add
appropriate write verifiers to all new metadata buffers.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:35:09 -06:00
Dave Chinner 612cfbfe17 xfs: add pre-write metadata buffer verifier callbacks
These verifiers are essentially the same code as the read verifiers,
but do not require ioend processing. Hence factor the read verifier
functions and add a new write verifier wrapper that is used as the
callback.

This is done as one large patch for all verifiers rather than one
patch per verifier as the change is largely mechanical. This
includes hooking up the write verifier via the read verifier
function.

Hooking up the write verifier for buffers obtained via
xfs_trans_get_buf() will be done in a separate patch as that touches
code in many different places rather than just the verifier
functions.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:35:02 -06:00
Dave Chinner d9392a4bb7 xfs: add xfs_da_node verification
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:34:55 -06:00
Dave Chinner ad14c33ac8 xfs: factor and verify attr leaf reads
Some reads are not converted yet because it isn't obvious ahead of
time what the format of the block is going to be. Need to determine
how to tell if the first block in the tree is a node or leaf format
block. That will be done in later patches.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:34:52 -06:00
Dave Chinner 4bb20a83a2 xfs: add verifier callback to directory read code
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-15 21:34:36 -06:00
Dave Chinner ee73259b40 xfs: add more attribute tree trace points.
Added when debugging recent attribute tree problems to more finely
trace code execution through the maze of twisty passages that makes
up the attr code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-13 14:47:00 -06:00
Dave Chinner 07428d7f0c xfs: fix attr tree double split corruption
In certain circumstances, a double split of an attribute tree is
needed to insert or replace an attribute. In rare situations, this
can go wrong, leaving the attribute tree corrupted. In this case,
the attr being replaced is the last attr in a leaf node, and the
replacement is larger so doesn't fit in the same leaf node.
When we have the initial condition of a node format attribute
btree with two leaves at index 1 and 2. Call them L1 and L2.  The
leaf L1 is completely full, there is not a single byte of free space
in it. L2 is mostly empty.  The attribute being replaced - call it X
- is the last attribute in L1.

The way an attribute replace is executed is that the replacement
attribute - call it Y - is first inserted into the tree, but has an
INCOMPLETE flag set on it so that list traversals ignore it. Once
this transaction is committed, a second transaction it run to
atomically mark Y as COMPLETE and X as INCOMPLETE, so that a
traversal will now find Y and skip X. Once that transaction is
committed, attribute X is then removed.

So, the initial condition is:

     +--------+     +--------+
     |   L1   |     |   L2   |
     | fwd: 2 |---->| fwd: 0 |
     | bwd: 0 |<----| bwd: 1 |
     | fsp: 0 |     | fsp: N |
     |--------|     |--------|
     | attr A |     | attr 1 |
     |--------|     |--------|
     | attr B |     | attr 2 |
     |--------|     |--------|
     ..........     ..........
     |--------|     |--------|
     | attr X |     | attr n |
     +--------+     +--------+


So now we go to replace X, and see that L1:fsp = 0 - it is full so
we can't insert Y in the same leaf. So we record the the location of
attribute X so we can track it for later use, then we split L1 into
L1 and L3 and reblance across the two leafs. We end with:


     +--------+     +--------+     +--------+
     |   L1   |     |   L3   |     |   L2   |
     | fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
     | bwd: 0 |<----| bwd: 1 |<----| bwd: 3 |
     | fsp: M |     | fsp: J |     | fsp: N |
     |--------|     |--------|     |--------|
     | attr A |     | attr X |     | attr 1 |
     |--------|     +--------+     |--------|
     | attr B |                    | attr 2 |
     |--------|                    |--------|
     ..........                    ..........
     |--------|                    |--------|
     | attr W |                    | attr n |
     +--------+                    +--------+


And we track that the original attribute is now at L3:0.

We then try to insert Y into L1 again, and find that there isn't
enough room because the new attribute is larger than the old one.
Hence we have to split again to make room for Y. We end up with
this:


     +--------+     +--------+     +--------+     +--------+
     |   L1   |     |   L4   |     |   L3   |     |   L2   |
     | fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
     | bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 |
     | fsp: M |     | fsp: J |     | fsp: J |     | fsp: N |
     |--------|     |--------|     |--------|     |--------|
     | attr A |     | attr Y |     | attr X |     | attr 1 |
     |--------|     + INCOMP +     +--------+     |--------|
     | attr B |     +--------+                    | attr 2 |
     |--------|                                   |--------|
     ..........                                   ..........
     |--------|                                   |--------|
     | attr W |                                   | attr n |
     +--------+                                   +--------+

And now we have the new (incomplete) attribute @ L4:0, and the
original attribute at L3:0. At this point, the first transaction is
committed, and we move to the flipping of the flags.

This is where we are supposed to end up with this:

     +--------+     +--------+     +--------+     +--------+
     |   L1   |     |   L4   |     |   L3   |     |   L2   |
     | fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
     | bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 |
     | fsp: M |     | fsp: J |     | fsp: J |     | fsp: N |
     |--------|     |--------|     |--------|     |--------|
     | attr A |     | attr Y |     | attr X |     | attr 1 |
     |--------|     +--------+     + INCOMP +     |--------|
     | attr B |                    +--------+     | attr 2 |
     |--------|                                   |--------|
     ..........                                   ..........
     |--------|                                   |--------|
     | attr W |                                   | attr n |
     +--------+                                   +--------+

But that doesn't happen properly - the attribute tracking indexes
are not pointing to the right locations. What we end up with is both
the old attribute to be removed pointing at L4:0 and the new
attribute at L4:1.  On a debug kernel, this assert fails like so:

XFS: Assertion failed: args->index2 < be16_to_cpu(leaf2->hdr.count), file: fs/xfs/xfs_attr_leaf.c, line: 2725

because the new attribute location does not exist. On a production
kernel, this goes unnoticed and the code proceeds ahead merrily and
removes L4 because it thinks that is the block that is no longer
needed. This leaves the hash index node pointing to entries
L1, L4 and L2, but only blocks L1, L3 and L2 to exist. Further, the
leaf level sibling list is L1 <-> L4 <-> L2, but L4 is now free
space, and so everything is busted. This corruption is caused by the
removal of the old attribute triggering a join - it joins everything
correctly but then frees the wrong block.

xfs_repair will report something like:

bad sibling back pointer for block 4 in attribute fork for inode 131
problem with attribute contents in inode 131
would clear attr fork
bad nblocks 8 for inode 131, would reset to 3
bad anextents 4 for inode 131, would reset to 0

The problem lies in the assignment of the old/new blocks for
tracking purposes when the double leaf split occurs. The first split
tries to place the new attribute inside the current leaf (i.e.
"inleaf == true") and moves the old attribute (X) to the new block.
This sets up the old block/index to L1:X, and newly allocated
block to L3:0. It then moves attr X to the new block and tries to
insert attr Y at the old index. That fails, so it splits again.

With the second split, the rebalance ends up placing the new attr in
the second new block - L4:0 - and this is where the code goes wrong.
What is does is it sets both the new and old block index to the
second new block. Hence it inserts attr Y at the right place (L4:0)
but overwrites the current location of the attr to replace that is
held in the new block index (currently L3:0). It over writes it with
L4:1 - the index we later assert fail on.

Hopefully this table will show this in a foramt that is a bit easier
to understand:

Split		old attr index		new attr index
		vanilla	patched		vanilla	patched
before 1st	L1:26	L1:26		N/A	N/A
after 1st	L3:0	L3:0		L1:26	L1:26
after 2nd	L4:0	L3:0		L4:1	L4:0
                ^^^^			^^^^
		wrong			wrong

The fix is surprisingly simple, for all this analysis - just stop
the rebalance on the out-of leaf case from overwriting the new attr
index - it's already correct for the double split case.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-13 14:45:29 -06:00
Dave Chinner 1d9025e561 xfs: remove struct xfs_dabuf and infrastructure
The struct xfs_dabuf now only tracks a single xfs_buf and all the
information it holds can be gained directly from the xfs_buf. Hence
we can remove the struct dabuf and pass the xfs_buf around
everywhere.

Kill the struct dabuf and the associated infrastructure.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-07-01 14:50:07 -05:00
Dave Chinner 60a34607b2 xfs: move xfsagino_t to xfs_types.h
Untangle the header file includes a bit by moving the definition of
xfs_agino_t to xfs_types.h. This removes the dependency that xfs_ag.h has on
xfs_inum.h, meaning we don't need to include xfs_inum.h everywhere we include
xfs_ag.h.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14 16:20:54 -05:00
Dave Chinner a8acad7073 xfs: kill XBF_LOCK
Buffers are always returned locked from the lookup routines. Hence
we don't need to tell the lookup routines to return locked buffers,
on to try and lock them. Remove XBF_LOCK from all the callers and
from internal buffer cache usage.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-05-14 16:20:50 -05:00
Dave Chinner 5a5881cdee xfs: add lots of attribute trace points
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-03-27 17:18:21 -05:00
Christoph Hellwig 8096b1ebb5 xfs: remove the if_ext_max field in struct xfs_ifork
We spent a lot of effort to maintain this field, but it always equals to the
fork size divided by the constant size of an extent.  The prime use of it is
to assert that the two stay in sync.  Just divide the fork size by the extent
size in the few places that we actually use it and remove the overhead
of maintaining it.  Also introduce a few helpers to consolidate the places
where we actually care about the value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2012-01-17 15:02:28 -06:00
Christoph Hellwig 4c393a6059 xfs: fix attr2 vs large data fork assert
With Dmitry fsstress updates I've seen very reproducible crashes in
xfs_attr_shortform_remove because xfs_attr_shortform_bytesfit claims that
the attributes would not fit inline into the inode after removing an
attribute.  It turns out that we were operating on an inode with lots
of delalloc extents, and thus an if_bytes values for the data fork that
is larger than biggest possible on-disk storage for it which utterly
confuses the code near the end of xfs_attr_shortform_bytesfit.

Fix this by always allowing the current attribute fork, like we already
do for the attr1 format, given that delalloc conversion will take care
for moving either the data or attribute area out of line if it doesn't
fit at that point - or making the point moot by merging extents at this
point.

Also document the function better, and clean up some loose bits.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
2011-11-29 13:03:12 -06:00
Dave Chinner 5c8ed2021f xfs: introduce xfs_bmapi_read()
xfs_bmapi() currently handles both extent map reading and
allocation. As a result, the code is littered with "if (wr)"
branches to conditionally do allocation operations if required.
This makes the code much harder to follow and causes significant
indent issues with the code.

Given that read mapping is much simpler than allocation, we can
split out read mapping from xfs_bmapi() and reuse the logic that
we have already factored out do do all the hard work of handling the
extent map manipulations. The results in a much simpler function for
the common extent read operations, and will allow the allocation
code to be simplified in another commit.

Once xfs_bmapi_read() is implemented, convert all the callers of
xfs_bmapi() that are only reading extents to use the new function.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2011-10-11 21:15:03 -05:00
Chandra Seetharaman 2a30f36d90 xfs: Check the return value of xfs_trans_get_buf()
Check the return value of xfs_trans_get_buf() and fail
appropriately.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2011-10-11 21:15:01 -05:00
Christoph Hellwig 69ef921b55 xfs: byteswap constants instead of variables
Micro-optimize various comparisms by always byteswapping the constant
instead of the variable, which allows to do the swap at compile instead
of runtime.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2011-07-08 14:36:05 +02:00
Dave Chinner 622d81494f xfs: use KM_NOFS for allocations during attribute list operations
When listing attributes, we are doiing memory allocations under the
inode ilock using only KM_SLEEP. This allows memory allocation to
recurse back into the filesystem and do writeback, which may the
ilock we already hold on the current inode. THis will deadlock.
Hence use KM_NOFS for such allocations outside of transaction
context to ensure that reclaim recursion does not occur.

Reported-by: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-12-23 11:57:37 +11:00
Christoph Hellwig b4e9181e77 xfs: remove unused delta tracking code in xfs_bmapi
This code was introduced four years ago in commit
3e57ecf640 without any review and has
been unused since.  Remove it just as the rest of the code introduced
in that commit to reduce that stack usage and complexity in this central
piece of code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:39 -05:00
Christoph Hellwig 3400777ff0 xfs: remove unneeded #include statements
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:33 -05:00
Christoph Hellwig 288699feca xfs: drop dmapi hooks
Dmapi support was never merged upstream, but we still have a lot of hooks
bloating XFS for it, all over the fast pathes of the filesystem.

This patch drops over 700 lines of dmapi overhead.  If we'll ever get HSM
support in mainline at least the namespace events can be done much saner
in the VFS instead of the individual filesystem, so it's not like this
is much help for future work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:33 -05:00
Christoph Hellwig 0cadda1c5f xfs: remove duplicate buffer flags
Currently we define aliases for the buffer flags in various
namespaces, which only adds confusion.  Remove all but the XBF_
flags to clean this up a bit.

Note that we still abuse XFS_B_ASYNC/XBF_ASYNC for some non-buffer
uses, but I'll clean that up later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-01-21 13:44:36 -06:00