Problem:
ec_getxattr_heal_cbk was called with NULL as second argument
in case heal was failing.
This function was dereferencing "cookie" argument which caused crash.

Solution:
Cookie is changed to carry the value that was supposed to be
stored in fop->data, so even in the case when fop is NULL in error
case, there won't be any NULL dereference.

Thanks to Xavi for the suggestion about the fix.

Change-Id: I0798000d5cadb17c3c2fbfa1baf77033ffc2bb8c
fixes: bz#1805057

When discard/truncate performs write fop, it should do so
after updating lock->good_mask to make sure readv happens
on the correct mask

fixes: bz#1805056
Change-Id: Idfef0bbcca8860d53707094722e6ba3f81c583b7
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

Problem:
when a file needs to be re-opened O_APPEND and O_EXCL
flags are not filtered in EC.

- O_APPEND should be filtered because EC doesn't send O_APPEND below EC for
open to make sure writes happen on the individual fragments instead of at the
end of the file.

- O_EXCL should be filtered because shd could have created the file so even
when file exists open should succeed

- O_CREAT should be filtered because open happens with gfid as parameter. So
open fop will create just the gfid which will lead to problems.

Fix:
Filter out these two flags in reopen.

Change-Id: Ia280470fcb5188a09caa07bf665a2a94bce23bc4
Fixes: bz#1805055
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

There are cases where fop->mask may have fop->healing added
and readv shouldn't be wound on fop->healing. To avoid this
always wind readv to lock->good_mask

fixes: bz#1805054
Change-Id: I2226ef0229daf5ff315d51e868b980ee48060b87
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

EC doesn't allow concurrent writes on overlapping areas, they are
serialized. However non-overlapping writes are serviced in parallel.
When a write is not aligned, EC first needs to read the entire chunk
from disk, apply the modified fragment and write it again.

The problem appears on sparse files because a write to an offset
implicitly creates data on offsets below it (so, in some way, they
are overlapping). For example, if a file is empty and we read 10 bytes
from offset 10, read() will return 0 bytes. Now, if we write one byte
at offset 1M and retry the same read, the system call will return 10
bytes (all containing 0's).

So if we have two writes, the first one at offset 10 and the second one
at offset 1M, EC will send both in parallel because they do not overlap.
However, the first one will try to read missing data from the first chunk
(i.e. offsets 0 to 9) to recombine the entire chunk and do the final write.
This read will happen in parallel with the write to 1M. What could happen
is that half of the bricks process the write before the read, and the
half do the read before the write. Some bricks will return 10 bytes of
data while the otherw will return 0 bytes (because the file on the brick
has not been expanded yet).

When EC tries to recombine the answers from the bricks, it can't, because
it needs more than half consistent answers to recover the data. So this
read fails with EIO error. This error is propagated to the parent write,
which is aborted and EIO is returned to the application.

The issue happened because EC assumed that a write to a given offset
implies that offsets below it exist.

This fix prevents the read of the chunk from bricks if the current size
of the file is smaller than the read chunk offset. This size is
correctly tracked, so this fixes the issue.

Also modifying ec-stripe.t file for Test #13 within it.
In this patch, if a file size is less than the offset we are writing, we
fill zeros in head and tail and do not consider it strip cache miss.
That actually make sense as we know what data that part holds and there is
no need of reading it from bricks.

Change-Id: Ic342e8c35c555b8534109e9314c9a0710b6225d6
Fixes: bz#1805053
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>

The ec_manager_open/opendir memsets ctx->loc which causes
memory/inode leak, and ec_fheal uses ctx->loc out of fd->lock
that loc_copy may copy bad data when memset it.

This patch skips updating ctx->loc when it is initilizaed.
With it, ctx->loc is filled once, and never updated.

Change-Id: I3bf5ffce4caf4c1c667f7acaa14b451d37a3550a
fixes: bz#1805052
Signed-off-by: Kinglong Mee <mijinlong@horiscale.com>

If lock has info, fop should inherit healing mask from it.
Otherwise, fop cannot inherit right healing when changed_flags is zero.

Change-Id: Ife80c9169d2c555024347a20300b0583f7e8a87f
fixes: bz#1805051
Signed-off-by: Kinglong Mee <mijinlong@horiscale.com>

Problem:
Race:
Thread-1                                    Thread-2
1) Does ec_get_size_version() to perform
pre-op fxattrop as part of write-1
                                           2) Calls ec_set_dirty_flag() in
                                              ec_get_size_version() for write-2.
					      This sets dirty[] to 1
3) Completes executing
ec_prepare_update_cbk leading to
ctx->dirty[] = '1'
					   4) Takes LOCK(inode->lock) to check if there are
					      any flags and sets dirty-flag because
				              lock->waiting_flag is 0 now. This leads to
					      fxattrop to increment on-disk dirty[] to '2'

At the end of the writes the file will be marked for heal even when it doesn't need heal.

Fix:
Perform ec_set_dirty_flag() and other checks inside LOCK() to prevent dirty[] to be marked
as '1' in step 2) above

Fixes: bz#1805050
Change-Id: Icac2ab39c0b1e7e154387800fbededc561612865
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

Problem:
Doing re-open with O_TRUNC will truncate the fragment even when it is not
needed needing extra heals

Fix:
At the time of re-open don't use O_TRUNC.

fixes: bz#1805049
Change-Id: Idc6408968efaad897b95a5a52481c66e843d3fb8
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

Currently EC tries to reopen fd's that have been opened while a brick
was down. This is done as part of regular write operations, just after
having acquired the locks, and it's sent as a sub-fop of the main write
fop.

There were two problems:

1. The reopen was attempted on all UP bricks, even if a previous lock
didn't succeed. This is incorrect because most probably the open will
fail.

2. If reopen is sent and fails, the error is propagated to the main
operation, causing it to fail when it shouldn't.

To fix this, we only attempt reopens on bricks where the current fop
owns a lock, and we prevent any error to be propagated to the main
fop.

To implement this behaviour an argument used to indicate the minimum
number of required answers has overloaded to also include some flags. To
make the change consistent, it has been necessary to rename the
argument, which means that a lot of files have been changed. However
there are no functional changes.

This change has also uncovered a problem in discard code, which didn't
correctely process requests of small sizes because no real discard fop
was being processed, only a write of 0's on some region. In this case
some fields of the fop remained uninitialized or with incorrect values.
To fix this, a new function has been created to simulate success on a
fop and it's used in the discard case.

Thanks to Pranith for providing a test script that has also detected an
issue in this patch. This patch includes a small modification of this
script to force data to be written into bricks before stopping them.

Change-Id: If272343873369186c2fb8f43c1d9c52c3ea304ec
Fixes: bz#1805047
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>