linux.git/fs/ceph/dir.c, branch v4.14

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

ceph: send LSSNAP request to auth mds of directory inode

2017-09-06T17:56:46+00:00

Snapdir inode has no capability. __choose_mds() should choose mds
base on capabilities of snapdir's parent inode.

Signed-off-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: fix race in concurrent readdir

2017-07-17T12:54:59+00:00

For a large directory, program needs to issue multiple readdir
syscalls to get all dentries. When there are multiple programs
read the directory concurrently. Following sequence of events
can happen.

 - program calls readdir with pos = 2. ceph sends readdir request
   to mds. The reply contains N1 entries. ceph adds these N1 entries
   to readdir cache.
 - program calls readdir with pos = N1+2. The readdir is satisfied
   by the readdir cache, N2 entries are returned. (Other program
   calls readdir in the middle, which fills the cache)
 - program calls readdir with pos = N1+N2+2. ceph sends readdir
   request to mds. The reply contains N3 entries and it reaches
   directory end. ceph adds these N3 entries to the readdir cache
   and marks directory complete.

The second readdir call does not update fi->readdir_cache_idx.
ceph add the last N3 entries to wrong places.

Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: choose readdir frag based on previous readdir reply

2017-05-04T07:19:24+00:00

The dirfragtree is lazily updated, it's not always accurate. Infinite
loops happens in following circumstance.

- client send request to read frag A
- frag A has been fragmented into frag B and C. So mds fills the reply
  with contents of frag B
- client wants to read next frag C. ceph_choose_frag(frag value of C)
  return frag A.

The fix is using previous readdir reply to calculate next readdir frag
when possible.

Signed-off-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: make seeky readdir more efficient

2017-05-04T07:19:20+00:00

Current cephfs client uses string to indicate start position of
readdir. The string is last entry of previous readdir reply.
This approach does not work for seeky readdir because we can
not easily convert the new postion to a string. For seeky readdir,
mds needs to return dentries from the beginning. Client keeps
retrying if the reply does not contain the dentry it wants.

In current version of ceph, mds sorts CDentry in its cache in
hash order. Client also uses dentry hash to compose dir postion.
For seeky readdir, if client passes the hash part of dir postion
to mds. mds can avoid replying useless dentries.

Signed-off-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov

ceph: do a LOOKUP in d_revalidate instead of GETATTR

2017-02-20T11:16:10+00:00

In commit c3f4688a08f (ceph: don't set req->r_locked_dir in
ceph_d_revalidate), we changed the code to do a GETATTR instead of a
LOOKUP as the parent info isn't strictly necessary to revalidate the
dentry. What we missed there though is that in order to update the lease
on the dentry after revalidating it, we _do_ need parent info.

Change ceph_d_revalidate back to doing a LOOKUP instead of a GETATTR so
that we can get the parent info in order to update the lease from
ceph_fill_trace. Note that we set req->r_parent here, but we cannot set
the CEPH_MDS_R_PARENT_LOCKED flag as we can't guarantee that it is.

Signed-off-by: Jeff Layton 
Reviewed-by: Yan, Zheng 
Signed-off-by: Ilya Dryomov

ceph: add a new flag to indicate whether parent is locked

2017-02-20T11:16:08+00:00

struct ceph_mds_request has an r_locked_dir pointer, which is set to
indicate the parent inode and that its i_rwsem is locked.  In some
critical places, we need to be able to indicate the parent inode to the
request handling code, even when its i_rwsem may not be locked.

Most of the code that operates on r_locked_dir doesn't require that the
i_rwsem be locked. We only really need it to handle manipulation of the
dcache. The rest (filling of the inode, updating dentry leases, etc.)
already has its own locking.

Add a new r_req_flags bit that indicates whether the parent is locked
when doing the request, and rename the pointer to "r_parent". For now,
all the places that set r_parent also set this flag, but that will
change in a later patch.

Signed-off-by: Jeff Layton 
Reviewed-by: Yan, Zheng 
Signed-off-by: Ilya Dryomov

ceph: convert bools in ceph_mds_request to a new r_req_flags field

2017-02-20T11:16:08+00:00

Currently, we have a bunch of bool flags in struct ceph_mds_request. We
need more flags though, but each bool takes (at least) a byte. Those
add up over time.

Merge all of the existing bools in this struct into a single unsigned
long, and use the set/test/clear_bit macros to manipulate them. These
are atomic operations, but that is required here to prevent
load/modify/store races. The existing flags are protected by different
locks, so we can't rely on them for that purpose.

Signed-off-by: Jeff Layton 
Reviewed-by: Yan, Zheng 
Signed-off-by: Ilya Dryomov

ceph: cleanup ACCESS_ONCE -> READ_ONCE

2017-02-20T11:16:05+00:00

This removes the uses of ACCESS_ONCE in favor of READ_ONCE

Signed-off-by: Seraphime Kirkovski 
Signed-off-by: Yan, Zheng

ceph: fix endianness of getattr mask in ceph_d_revalidate

2017-01-18T16:58:45+00:00

sparse says:

    fs/ceph/dir.c:1248:50: warning: incorrect type in assignment (different base types)
    fs/ceph/dir.c:1248:50:    expected restricted __le32 [usertype] mask
    fs/ceph/dir.c:1248:50:    got int [signed] [assigned] mask

Fixes: 200fd27c8fa2 ("ceph: use lookup request to revalidate dentry")
Signed-off-by: Jeff Layton 
Reviewed-by: Sage Weil 
Signed-off-by: Ilya Dryomov