Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended attributes and file attributes are available in GCache/v1/files to distinguish removable Drive caches. However, it is not true for ephemral mode, in which tmpfs is used to mount user directory. As a result in ephemeral mode initialization of file caches always fails and thus Drive folder doesn't appear in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem doesn't support it. We compute the availability by checking if the errno is ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.

Committed: https://crrev.com/7bd26bbf49860786603601e1aae0f9407a4c1292
Cr-Commit-Position: refs/heads/master@{#425263}

[oka, 2016-10-12 09:50:49]

Description was changed from

==========
Cryptohome bugfix.

BUG=
==========

to

==========
Cryptohome bugfix.

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

[oka, 2016-10-12 09:50:49]

oka@chromium.org changed reviewers:
+ fukino@chromium.org

[oka, 2016-10-12 09:51:51]

PTAL.

[oka, 2016-10-12 09:52:03]

Description was changed from

==========
Cryptohome bugfix.

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

[oka, 2016-10-12 09:52:17]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

[oka, 2016-10-12 09:54:42]

The CQ bit was checked by oka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-12 09:54:54]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-12 10:27:27]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-12 10:27:28]

Dry run: This issue passed the CQ dry run.

[fukino, 2016-10-12 10:34:29]

In the bug description, please mention:
- What was wrong with https://codereview.chromium.org/2006503002.
- How this CL fixes the problem.
- (optional) Why we need to choose workaround for it. How complex is a proper
fix going to?

Also, let me add hashomoto@ for the reviewer, who should be familiar with the
drive cache and the previous CL.

https://codereview.chromium.org/2412063002/diff/20001/components/drive/chrome...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/20001/components/drive/chrome...
components/drive/chromeos/file_cache.cc:99: // filesystem does not support file
attributes, as tmpfs for ephemeral mode.
Can we just return at the beginning of this function at the beginning of
FixMetadataAndFileAttributes() when we are on tmpfs?

[fukino, 2016-10-12 10:34:56]

fukino@chromium.org changed reviewers:
+ hashimoto@chromium.org

[fukino, 2016-10-12 10:34:56]

In the bug description, please mention:
- What was wrong with https://codereview.chromium.org/2006503002.
- How this CL fixes the problem.
- (optional) Why we need to choose workaround for it. How complex is a proper
fix going to?

Also, let me add hashomoto@ for the reviewer, who should be familiar with the
drive cache and the previous CL.

[oka, 2016-10-13 05:42:32]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

BUG=650268
TEST=Confirmed on ephemeral mode Drive appears in Files App and copy & paste
between Download and Drive, Drive and Drive are successfully done using link.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue just by ignoring errors happen in attempts to update
caches' (extended) file attributes.
Given the issue is P1 and the fix is wanted to be cherry-picked to M55 by Oct.
14, I keep the CL as straightforward as possible.
Proper fix would be not to touch file attributes at all if underlying filesystem
doesn't support it, but since it's rather complex I'll do it in subsequent
CL(s).

BUG=650268
TEST=Using link, confirmed on ephemeral mode Drive appears in Files App and copy
& paste between Download and Drive, Drive and Drive are successfully done.
==========

[oka, 2016-10-13 05:43:00]

On 2016/10/12 10:34:56, fukino wrote:
> In the bug description, please mention:
> - What was wrong with https://codereview.chromium.org/2006503002.
> - How this CL fixes the problem.
> - (optional) Why we need to choose workaround for it. How complex is a proper
> fix going to?
> 
> Also, let me add hashomoto@ for the reviewer, who should be familiar with the
> drive cache and the previous CL.

Done. PTAL.

[oka, 2016-10-13 05:55:51]

https://codereview.chromium.org/2412063002/diff/20001/components/drive/chrome...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/20001/components/drive/chrome...
components/drive/chromeos/file_cache.cc:99: // filesystem does not support file
attributes, as tmpfs for ephemeral mode.
On 2016/10/12 10:34:29, fukino wrote:
> Can we just return at the beginning of this function at the beginning of
> FixMetadataAndFileAttributes() when we are on tmpfs?

That's right. I updated the TODO comment.

[oka, 2016-10-13 05:59:20]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue just by ignoring errors happen in attempts to update
caches' (extended) file attributes.
Given the issue is P1 and the fix is wanted to be cherry-picked to M55 by Oct.
14, I keep the CL as straightforward as possible.
Proper fix would be not to touch file attributes at all if underlying filesystem
doesn't support it, but since it's rather complex I'll do it in subsequent
CL(s).

BUG=650268
TEST=Using link, confirmed on ephemeral mode Drive appears in Files App and copy
& paste between Download and Drive, Drive and Drive are successfully done.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue just by ignoring errors happen in attempts to get/set
caches' (extended) file attributes.
Given the issue is P1 and the fix is wanted to be cherry-picked to M55 by Oct.
14, I keep the CL as straightforward as possible.
Proper fix would be not to touch file attributes at all if underlying filesystem
doesn't support it, but since it's rather complex I'll do it in subsequent
CL(s).

BUG=650268
TEST=Using link, confirmed on ephemeral mode Drive appears in Files App and copy
& paste between Download and Drive, Drive and Drive are successfully done.
==========

[hashimoto, 2016-10-13 06:12:07]

https://codereview.chromium.org/2412063002/diff/40001/components/drive/chrome...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/40001/components/drive/chrome...
components/drive/chromeos/file_cache.cc:103: // TODO(oka): false should be
returned.
This can result in ignoring real errors and this sounds scary to me.
As fukino@ said, can't you change the behavior only on file systems which don't
support attributes?
For example, by using statfs
(http://stackoverflow.com/questions/26635846/how-to-tell-if-a-file-is-on-tmpfs...),
or by checking errno after xattr to see if it's ENOTSUP.

[oka, 2016-10-13 22:30:45]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue just by ignoring errors happen in attempts to get/set
caches' (extended) file attributes.
Given the issue is P1 and the fix is wanted to be cherry-picked to M55 by Oct.
14, I keep the CL as straightforward as possible.
Proper fix would be not to touch file attributes at all if underlying filesystem
doesn't support it, but since it's rather complex I'll do it in subsequent
CL(s).

BUG=650268
TEST=Using link, confirmed on ephemeral mode Drive appears in Files App and copy
& paste between Download and Drive, Drive and Drive are successfully done.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link, the following are confirmed on ephemeral mode.
- Drive appears in Files App.
- Copy & paste between Download and Drive, Drive and Drive are successfully
done.
- Pin/unpin on Drive works.
- /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
==========

[oka, 2016-10-13 22:34:23]

Update comment.

[oka, 2016-10-14 02:36:43]

PTAL.

https://codereview.chromium.org/2412063002/diff/40001/components/drive/chrome...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/40001/components/drive/chrome...
components/drive/chromeos/file_cache.cc:103: // TODO(oka): false should be
returned.
On 2016/10/13 06:12:06, hashimoto wrote:
> This can result in ignoring real errors and this sounds scary to me.
> As fukino@ said, can't you change the behavior only on file systems which
don't
> support attributes?
> For example, by using statfs
>
(http://stackoverflow.com/questions/26635846/how-to-tell-if-a-file-is-on-tmpfs...),
> or by checking errno after xattr to see if it's ENOTSUP.

Done.

Thank you. I used xattr.

[oka, 2016-10-14 02:40:20]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link, the following are confirmed on ephemeral mode.
- Drive appears in Files App.
- Copy & paste between Download and Drive, Drive and Drive are successfully
done.
- Pin/unpin on Drive works.
- /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pined/unpined.
==========

[oka, 2016-10-14 02:40:36]

PTAL.

[oka, 2016-10-14 03:30:37]

The CQ bit was checked by oka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-14 03:30:50]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-14 03:54:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-14 03:54:54]

Dry run: This issue passed the CQ dry run.

[oka, 2016-10-14 03:57:10]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pined/unpined.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

[hashimoto, 2016-10-14 04:16:49]

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:59: getxattr(path.value().c_str(),
"user.foo", nullptr, 0);
Please check that getxattr actually fails.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:66: if
(!IsFileAttributesSupported(path)) {
Isn't it better to check this at the beginning of MarkAsDriveCacheDir instead?

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:108: if
(!IsFileAttributesSupported(path)) {
It'd be nice to have a brief comment to justify this early-return.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:120: if
(!IsFileAttributesSupported(path)) {
ditto.

[oka, 2016-10-14 04:36:01]

The CQ bit was checked by oka@chromium.org to run a CQ dry run

[oka, 2016-10-14 04:36:06]

PTAL.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:59: getxattr(path.value().c_str(),
"user.foo", nullptr, 0);
On 2016/10/14 04:16:49, hashimoto wrote:
> Please check that getxattr actually fails.

Done.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:66: if
(!IsFileAttributesSupported(path)) {
On 2016/10/14 04:16:49, hashimoto wrote:
> Isn't it better to check this at the beginning of MarkAsDriveCacheDir instead?

Done.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:108: if
(!IsFileAttributesSupported(path)) {
On 2016/10/14 04:16:48, hashimoto wrote:
> It'd be nice to have a brief comment to justify this early-return.

Done.

https://codereview.chromium.org/2412063002/diff/120001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:120: if
(!IsFileAttributesSupported(path)) {
On 2016/10/14 04:16:48, hashimoto wrote:
> ditto.

Done.

[commit-bot: I haz the power, 2016-10-14 04:36:12]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[hashimoto, 2016-10-14 04:44:44]

lgtm thanks!

https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:138: if
(!IsFileAttributesSupported(path)) {
Please add a comment like the ones in SetRemovable and UnsetRemovable

[oka, 2016-10-14 04:50:22]

Address comments.

[oka, 2016-10-14 04:50:32]

On 2016/10/14 04:44:44, hashimoto wrote:
> lgtm thanks!
> 
>
https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
> File components/drive/chromeos/file_cache.cc (right):
> 
>
https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
> components/drive/chromeos/file_cache.cc:138: if
> (!IsFileAttributesSupported(path)) {
> Please add a comment like the ones in SetRemovable and UnsetRemovable

Thank you!

[oka, 2016-10-14 04:50:39]

https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
File components/drive/chromeos/file_cache.cc (right):

https://codereview.chromium.org/2412063002/diff/140001/components/drive/chrom...
components/drive/chromeos/file_cache.cc:138: if
(!IsFileAttributesSupported(path)) {
On 2016/10/14 04:44:44, hashimoto wrote:
> Please add a comment like the ones in SetRemovable and UnsetRemovable

Done.

[fukino, 2016-10-14 06:06:31]

lgtm

[oka, 2016-10-14 06:34:30]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

[oka, 2016-10-14 06:34:41]

The CQ bit was checked by oka@chromium.org

[oka, 2016-10-14 06:34:41]

The patchset sent to the CQ was uploaded after l-g-t-m from
hashimoto@chromium.org
Link to the patchset: https://codereview.chromium.org/2412063002/#ps160001
(title: "Address comments.")

[commit-bot: I haz the power, 2016-10-14 06:34:52]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-14 06:59:28]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

[commit-bot: I haz the power, 2016-10-14 06:59:29]

Committed patchset #9 (id:160001)

[commit-bot: I haz the power, 2016-10-14 07:01:29]

Description was changed from

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.
==========

to

==========
Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

The CL https://codereview.chromium.org/2006503002 assumed file extended
attributes and file attributes are available in GCache/v1/files to distinguish
removable Drive caches. However, it is not true for ephemral mode, in which
tmpfs is used to mount user directory. As a result in ephemeral mode
initialization of file caches always fails and thus Drive folder doesn't appear
in Files App.
This CL fixes the issue by not touching file attributes if underlying filesystem
doesn't support it. We compute the availability by checking if the errno is
ENOTSUP after xattr() is called.

BUG=650268
TEST=Using link and daisy,
- on phemeral mode,
  - Drive appears in Files App.
  - Copy & paste between Download and Drive, Drive and Drive are successfully
done.
  - Pin/unpin on Drive works.
  - /var/log/ui/ui.LATEST doesn't report any error in file_cache.cc .
- on normal mode,
  - GCache/v1/files has +d attribute and user.GCacheFiles extended attribute.
  - +d file attribute is toggled as expected when a file is pinned/unpinned.

Committed: https://crrev.com/7bd26bbf49860786603601e1aae0f9407a4c1292
Cr-Commit-Position: refs/heads/master@{#425263}
==========

[commit-bot: I haz the power, 2016-10-14 07:01:30]

Patchset 9 (id:??) landed as
https://crrev.com/7bd26bbf49860786603601e1aae0f9407a4c1292
Cr-Commit-Position: refs/heads/master@{#425263}