linux/fs/ext4/page-io.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
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 <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

538 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/page-io.c
*
* This contains the new page_io functions for ext4
*
* Written by Theodore Ts'o, 2010.
*/
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/mpage.h>
#include <linux/namei.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include <linux/workqueue.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
static struct kmem_cache *io_end_cachep;
int __init ext4_init_pageio(void)
{
io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT);
if (io_end_cachep == NULL)
return -ENOMEM;
return 0;
}
void ext4_exit_pageio(void)
{
kmem_cache_destroy(io_end_cachep);
}
/*
* Print an buffer I/O error compatible with the fs/buffer.c. This
* provides compatibility with dmesg scrapers that look for a specific
* buffer I/O error message. We really need a unified error reporting
* structure to userspace ala Digital Unix's uerf system, but it's
* probably not going to happen in my lifetime, due to LKML politics...
*/
static void buffer_io_error(struct buffer_head *bh)
{
printk_ratelimited(KERN_ERR "Buffer I/O error on device %pg, logical block %llu\n",
bh->b_bdev,
(unsigned long long)bh->b_blocknr);
}
static void ext4_finish_bio(struct bio *bio)
{
int i;
struct bio_vec *bvec;
bio_for_each_segment_all(bvec, bio, i) {
struct page *page = bvec->bv_page;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
struct page *data_page = NULL;
#endif
struct buffer_head *bh, *head;
unsigned bio_start = bvec->bv_offset;
unsigned bio_end = bio_start + bvec->bv_len;
unsigned under_io = 0;
unsigned long flags;
if (!page)
continue;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
if (!page->mapping) {
/* The bounce data pages are unmapped. */
data_page = page;
fscrypt_pullback_bio_page(&page, false);
}
#endif
if (bio->bi_status) {
SetPageError(page);
mapping_set_error(page->mapping, -EIO);
}
bh = head = page_buffers(page);
/*
* We check all buffers in the page under BH_Uptodate_Lock
* to avoid races with other end io clearing async_write flags
*/
local_irq_save(flags);
bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
do {
if (bh_offset(bh) < bio_start ||
bh_offset(bh) + bh->b_size > bio_end) {
if (buffer_async_write(bh))
under_io++;
continue;
}
clear_buffer_async_write(bh);
if (bio->bi_status)
buffer_io_error(bh);
} while ((bh = bh->b_this_page) != head);
bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
local_irq_restore(flags);
if (!under_io) {
#ifdef CONFIG_EXT4_FS_ENCRYPTION
if (data_page)
fscrypt_restore_control_page(data_page);
#endif
end_page_writeback(page);
}
}
}
static void ext4_release_io_end(ext4_io_end_t *io_end)
{
struct bio *bio, *next_bio;
BUG_ON(!list_empty(&io_end->list));
BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
WARN_ON(io_end->handle);
for (bio = io_end->bio; bio; bio = next_bio) {
next_bio = bio->bi_private;
ext4_finish_bio(bio);
bio_put(bio);
}
kmem_cache_free(io_end_cachep, io_end);
}
/*
* Check a range of space and convert unwritten extents to written. Note that
* we are protected from truncate touching same part of extent tree by the
* fact that truncate code waits for all DIO to finish (thus exclusion from
* direct IO is achieved) and also waits for PageWriteback bits. Thus we
* cannot get to ext4_ext_truncate() before all IOs overlapping that range are
* completed (happens from ext4_free_ioend()).
*/
static int ext4_end_io(ext4_io_end_t *io)
{
struct inode *inode = io->inode;
loff_t offset = io->offset;
ssize_t size = io->size;
handle_t *handle = io->handle;
int ret = 0;
ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
"list->prev 0x%p\n",
io, inode->i_ino, io->list.next, io->list.prev);
io->handle = NULL; /* Following call will use up the handle */
ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
ext4_msg(inode->i_sb, KERN_EMERG,
"failed to convert unwritten extents to written "
"extents -- potential data loss! "
"(inode %lu, offset %llu, size %zd, error %d)",
inode->i_ino, offset, size, ret);
}
ext4_clear_io_unwritten_flag(io);
ext4_release_io_end(io);
return ret;
}
static void dump_completed_IO(struct inode *inode, struct list_head *head)
{
#ifdef EXT4FS_DEBUG
struct list_head *cur, *before, *after;
ext4_io_end_t *io, *io0, *io1;
if (list_empty(head))
return;
ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
list_for_each_entry(io, head, list) {
cur = &io->list;
before = cur->prev;
io0 = container_of(before, ext4_io_end_t, list);
after = cur->next;
io1 = container_of(after, ext4_io_end_t, list);
ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
io, inode->i_ino, io0, io1);
}
#endif
}
/* Add the io_end to per-inode completed end_io list. */
static void ext4_add_complete_io(ext4_io_end_t *io_end)
{
struct ext4_inode_info *ei = EXT4_I(io_end->inode);
struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb);
struct workqueue_struct *wq;
unsigned long flags;
/* Only reserved conversions from writeback should enter here */
WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
WARN_ON(!io_end->handle && sbi->s_journal);
spin_lock_irqsave(&ei->i_completed_io_lock, flags);
wq = sbi->rsv_conversion_wq;
if (list_empty(&ei->i_rsv_conversion_list))
queue_work(wq, &ei->i_rsv_conversion_work);
list_add_tail(&io_end->list, &ei->i_rsv_conversion_list);
spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
}
static int ext4_do_flush_completed_IO(struct inode *inode,
struct list_head *head)
{
ext4_io_end_t *io;
struct list_head unwritten;
unsigned long flags;
struct ext4_inode_info *ei = EXT4_I(inode);
int err, ret = 0;
spin_lock_irqsave(&ei->i_completed_io_lock, flags);
dump_completed_IO(inode, head);
list_replace_init(head, &unwritten);
spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
while (!list_empty(&unwritten)) {
io = list_entry(unwritten.next, ext4_io_end_t, list);
BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
list_del_init(&io->list);
err = ext4_end_io(io);
if (unlikely(!ret && err))
ret = err;
}
return ret;
}
/*
* work on completed IO, to convert unwritten extents to extents
*/
void ext4_end_io_rsv_work(struct work_struct *work)
{
struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info,
i_rsv_conversion_work);
ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list);
}
ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
{
ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
if (io) {
io->inode = inode;
INIT_LIST_HEAD(&io->list);
atomic_set(&io->count, 1);
}
return io;
}
void ext4_put_io_end_defer(ext4_io_end_t *io_end)
{
if (atomic_dec_and_test(&io_end->count)) {
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) {
ext4_release_io_end(io_end);
return;
}
ext4_add_complete_io(io_end);
}
}
int ext4_put_io_end(ext4_io_end_t *io_end)
{
int err = 0;
if (atomic_dec_and_test(&io_end->count)) {
if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
err = ext4_convert_unwritten_extents(io_end->handle,
io_end->inode, io_end->offset,
io_end->size);
io_end->handle = NULL;
ext4_clear_io_unwritten_flag(io_end);
}
ext4_release_io_end(io_end);
}
return err;
}
ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end)
{
atomic_inc(&io_end->count);
return io_end;
}
/* BIO completion function for page writeback */
static void ext4_end_bio(struct bio *bio)
{
ext4_io_end_t *io_end = bio->bi_private;
sector_t bi_sector = bio->bi_iter.bi_sector;
char b[BDEVNAME_SIZE];
if (WARN_ONCE(!io_end, "io_end is NULL: %s: sector %Lu len %u err %d\n",
bio_devname(bio, b),
(long long) bio->bi_iter.bi_sector,
(unsigned) bio_sectors(bio),
bio->bi_status)) {
ext4_finish_bio(bio);
bio_put(bio);
return;
}
bio->bi_end_io = NULL;
if (bio->bi_status) {
struct inode *inode = io_end->inode;
ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu "
"(offset %llu size %ld starting block %llu)",
bio->bi_status, inode->i_ino,
(unsigned long long) io_end->offset,
(long) io_end->size,
(unsigned long long)
bi_sector >> (inode->i_blkbits - 9));
mapping_set_error(inode->i_mapping,
blk_status_to_errno(bio->bi_status));
}
if (io_end->flag & EXT4_IO_END_UNWRITTEN) {
/*
* Link bio into list hanging from io_end. We have to do it
* atomically as bio completions can be racing against each
* other.
*/
bio->bi_private = xchg(&io_end->bio, bio);
ext4_put_io_end_defer(io_end);
} else {
/*
* Drop io_end reference early. Inode can get freed once
* we finish the bio.
*/
ext4_put_io_end_defer(io_end);
ext4_finish_bio(bio);
bio_put(bio);
}
}
void ext4_io_submit(struct ext4_io_submit *io)
{
struct bio *bio = io->io_bio;
if (bio) {
int io_op_flags = io->io_wbc->sync_mode == WB_SYNC_ALL ?
REQ_SYNC : 0;
io->io_bio->bi_write_hint = io->io_end->inode->i_write_hint;
bio_set_op_attrs(io->io_bio, REQ_OP_WRITE, io_op_flags);
submit_bio(io->io_bio);
}
io->io_bio = NULL;
}
void ext4_io_submit_init(struct ext4_io_submit *io,
struct writeback_control *wbc)
{
io->io_wbc = wbc;
io->io_bio = NULL;
io->io_end = NULL;
}
static int io_submit_init_bio(struct ext4_io_submit *io,
struct buffer_head *bh)
{
struct bio *bio;
bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
if (!bio)
return -ENOMEM;
wbc_init_bio(io->io_wbc, bio);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio_set_dev(bio, bh->b_bdev);
bio->bi_end_io = ext4_end_bio;
bio->bi_private = ext4_get_io_end(io->io_end);
io->io_bio = bio;
io->io_next_block = bh->b_blocknr;
return 0;
}
static int io_submit_add_bh(struct ext4_io_submit *io,
struct inode *inode,
struct page *page,
struct buffer_head *bh)
{
int ret;
if (io->io_bio && bh->b_blocknr != io->io_next_block) {
submit_and_retry:
ext4_io_submit(io);
}
if (io->io_bio == NULL) {
ret = io_submit_init_bio(io, bh);
if (ret)
return ret;
io->io_bio->bi_write_hint = inode->i_write_hint;
}
ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh));
if (ret != bh->b_size)
goto submit_and_retry;
wbc_account_io(io->io_wbc, page, bh->b_size);
io->io_next_block++;
return 0;
}
int ext4_bio_write_page(struct ext4_io_submit *io,
struct page *page,
int len,
struct writeback_control *wbc,
bool keep_towrite)
{
struct page *data_page = NULL;
struct inode *inode = page->mapping->host;
unsigned block_start;
struct buffer_head *bh, *head;
int ret = 0;
int nr_submitted = 0;
int nr_to_submit = 0;
BUG_ON(!PageLocked(page));
BUG_ON(PageWriteback(page));
if (keep_towrite)
set_page_writeback_keepwrite(page);
else
set_page_writeback(page);
ClearPageError(page);
/*
* Comments copied from block_write_full_page:
*
* The page straddles i_size. It must be zeroed out on each and every
* writepage invocation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
if (len < PAGE_SIZE)
zero_user_segment(page, len, PAGE_SIZE);
/*
* In the first loop we prepare and mark buffers to submit. We have to
* mark all buffers in the page before submitting so that
* end_page_writeback() cannot be called from ext4_bio_end_io() when IO
* on the first buffer finishes and we are still working on submitting
* the second buffer.
*/
bh = head = page_buffers(page);
do {
block_start = bh_offset(bh);
if (block_start >= len) {
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
continue;
}
if (!buffer_dirty(bh) || buffer_delay(bh) ||
!buffer_mapped(bh) || buffer_unwritten(bh)) {
/* A hole? We can safely clear the dirty bit */
if (!buffer_mapped(bh))
clear_buffer_dirty(bh);
if (io->io_bio)
ext4_io_submit(io);
continue;
}
if (buffer_new(bh)) {
clear_buffer_new(bh);
clean_bdev_bh_alias(bh);
}
set_buffer_async_write(bh);
nr_to_submit++;
} while ((bh = bh->b_this_page) != head);
bh = head = page_buffers(page);
if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode) &&
nr_to_submit) {
gfp_t gfp_flags = GFP_NOFS;
retry_encrypt:
data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
page->index, gfp_flags);
if (IS_ERR(data_page)) {
ret = PTR_ERR(data_page);
if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
if (io->io_bio) {
ext4_io_submit(io);
congestion_wait(BLK_RW_ASYNC, HZ/50);
}
gfp_flags |= __GFP_NOFAIL;
goto retry_encrypt;
}
data_page = NULL;
goto out;
}
}
/* Now submit buffers to write */
do {
if (!buffer_async_write(bh))
continue;
ret = io_submit_add_bh(io, inode,
data_page ? data_page : page, bh);
if (ret) {
/*
* We only get here on ENOMEM. Not much else
* we can do but mark the page as dirty, and
* better luck next time.
*/
break;
}
nr_submitted++;
clear_buffer_dirty(bh);
} while ((bh = bh->b_this_page) != head);
/* Error stopped previous loop? Clean up buffers... */
if (ret) {
out:
if (data_page)
fscrypt_restore_control_page(data_page);
printk_ratelimited(KERN_ERR "%s: ret = %d\n", __func__, ret);
redirty_page_for_writepage(wbc, page);
do {
clear_buffer_async_write(bh);
bh = bh->b_this_page;
} while (bh != head);
}
unlock_page(page);
/* Nothing submitted - we have to end page writeback */
if (!nr_submitted)
end_page_writeback(page);
return ret;
}