wireguard-linux/fs/ext4/xattr.h, branch jd/unified-crypt-queue

ext4: use flexible-array member for xattr structs

2020-03-14T18:43:13Z

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20200309180813.GA3347@embeddedor Signed-off-by: Theodore Ts'o

ext4: add extra checks to ext4_xattr_block_get()

2018-03-31T00:04:11Z

Add explicit checks in ext4_xattr_block_get() just in case the e_value_offs and e_value_size fields in the the xattr block are corrupted in memory after the buffer_verified bit is set on the xattr block. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

ext4: fix up remaining files with SPDX cleanups

2017-12-18T03:00:59Z

A number of ext4 source files were skipped due because their copyright permission statements didn't match the expected text used by the automated conversion utilities. I've added SPDX tags for the rest. While looking at some of these files, I've noticed that we have quite a bit of variation on the licenses that were used --- in particular some of the Red Hat licenses on the jbd2 files use a GPL2+ license, and we have some files that have a LGPL-2.1 license (which was quite surprising). I've not attempted to do any license changes. Even if it is perfectly legal to relicense to GPL 2.0-only for consistency's sake, that should be done with ext4 developer community discussion. Signed-off-by: Theodore Ts'o

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

2017-11-02T10:10:55Z

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

ext4: fix __ext4_new_inode() journal credits calculation

2017-07-06T04:01:59Z

ea_inode feature allows creating extended attributes that are up to 64k in size. Update __ext4_new_inode() to pick increased credit limits. To avoid overallocating too many journal credits, update __ext4_xattr_set_credits() to make a distinction between xattr create vs update. This helps __ext4_new_inode() because all attributes are known to be new, so we can save credits that are normally needed to delete old values. Also, have fscrypt specify its maximum context size so that we don't end up allocating credits for 64k size. Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o

quota: add get_inode_usage callback to transfer multi-inode charges

2017-06-22T15:46:48Z

Ext4 ea_inode feature allows storing xattr values in external inodes to be able to store values that are bigger than a block in size. Ext4 also has deduplication support for these type of inodes. With deduplication, the actual storage waste is eliminated but the users of such inodes are still charged full quota for the inodes as if there was no sharing happening in the background. This design requires ext4 to manually charge the users because the inodes are shared. An implication of this is that, if someone calls chown on a file that has such references we need to transfer the quota for the file and xattr inodes. Current dquot_transfer() function implicitly transfers one inode charge. With ea_inode feature, we would like to transfer multiple inode charges. Add get_inode_usage callback which can interrogate the total number of inodes that were charged for a given inode. [ Applied fix from Colin King to make sure the 'ret' variable is initialized on the successful return path. Detected by CoverityScan, CID#1446616 ("Uninitialized scalar variable") --tytso] Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o Signed-off-by: Colin Ian King Acked-by: Jan Kara

ext4: xattr inode deduplication

2017-06-22T15:44:55Z

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable. The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes. The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted. The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged. [ Fixed up journal credits calculation to handle inline data and the rare case where an shared xattr block can get freed when two thread race on breaking the xattr block sharing. --tytso ] Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o

ext4: cleanup transaction restarts during inode deletion

2017-06-22T15:42:09Z

During inode deletion, the number of journal credits that will be needed is hard to determine. For that reason we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call. Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference. Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o

ext4: move struct ext4_xattr_inode_array to xattr.h

2017-06-22T14:28:38Z

Since this is a xattr specific data structure it is cleaner to keep it in xattr header file. Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o

ext4: modify ext4_xattr_ino_array to hold struct inode *

2017-06-22T14:26:31Z

Tracking struct inode * rather than the inode number eliminates the repeated ext4_xattr_inode_iget() call later. The second call cannot fail in practice but still requires explanation when it wants to ignore the return value. Avoid the trouble and make things simple. Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o