On 30/10/2019 03.20, kbuild test robot wrote:
Hi Konstantin,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v5.4-rc5 next-20191029]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Konstantin-Khlebnikov/fs-warn-if-stale-pagecache-is-left-after-direct-write/20191030-073543
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 23fdb198ae81f47a574296dab5167c5e136a02ba
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-14) 7.4.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
All errors (new ones prefixed by >>):
mm/filemap.c: In function 'generic_file_direct_write':
mm/filemap.c:3229:3: error: implicit declaration of function 'dio_warn_stale_pagecache'; did you mean 'truncate_pagecache'? [-Werror=implicit-function-declaration]
dio_warn_stale_pagecache(file);
^~~~~~~~~~~~~~~~~~~~~~~~
truncate_pagecache
cc1: some warnings being treated as errors
This config has CONFIG_BLOCK=n while O_DIRECT is still here.
For example, NFS has it too.
I'll move dio_warn_stale_pagecache() into different file.
vim +3229 mm/filemap.c
3163
3164 ssize_t
3165 generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
3166 {
3167 struct file *file = iocb->ki_filp;
3168 struct address_space *mapping = file->f_mapping;
3169 struct inode *inode = mapping->host;
3170 loff_t pos = iocb->ki_pos;
3171 ssize_t written;
3172 size_t write_len;
3173 pgoff_t end;
3174
3175 write_len = iov_iter_count(from);
3176 end = (pos + write_len - 1) >> PAGE_SHIFT;
3177
3178 if (iocb->ki_flags & IOCB_NOWAIT) {
3179 /* If there are pages to writeback, return */
3180 if (filemap_range_has_page(inode->i_mapping, pos,
3181 pos + write_len - 1))
3182 return -EAGAIN;
3183 } else {
3184 written = filemap_write_and_wait_range(mapping, pos,
3185 pos + write_len - 1);
3186 if (written)
3187 goto out;
3188 }
3189
3190 /*
3191 * After a write we want buffered reads to be sure to go to disk to get
3192 * the new data. We invalidate clean cached page from the region we're
3193 * about to write. We do this *before* the write so that we can return
3194 * without clobbering -EIOCBQUEUED from ->direct_IO().
3195 */
3196 written = invalidate_inode_pages2_range(mapping,
3197 pos >> PAGE_SHIFT, end);
3198 /*
3199 * If a page can not be invalidated, return 0 to fall back
3200 * to buffered write.
3201 */
3202 if (written) {
3203 if (written == -EBUSY)
3204 return 0;
3205 goto out;
3206 }
3207
3208 written = mapping->a_ops->direct_IO(iocb, from);
3209
3210 /*
3211 * Finally, try again to invalidate clean pages which might have been
3212 * cached by non-direct readahead, or faulted in by get_user_pages()
3213 * if the source of the write was an mmap'ed region of the file
3214 * we're writing. Either one is a pretty crazy thing to do,
3215 * so we don't support it 100%. If this invalidation
3216 * fails, tough, the write still worked...
3217 *
3218 * Most of the time we do not need this since dio_complete() will do
3219 * the invalidation for us. However there are some file systems that
3220 * do not end up with dio_complete() being called, so let's not break
3221 * them by removing it completely.
3222 *
3223 * Noticeable case is a blkdev_direct_IO().
3224 *
3225 * Skip invalidation for async writes or if mapping has no pages.
3226 */
3227 if (written > 0 && mapping->nrpages &&
3228 invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, end))
3229 dio_warn_stale_pagecache(file);
3230
3231 if (written > 0) {
3232 pos += written;
3233 write_len -= written;
3234 if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
3235 i_size_write(inode, pos);
3236 mark_inode_dirty(inode);
3237 }
3238 iocb->ki_pos = pos;
3239 }
3240 iov_iter_revert(from, write_len - iov_iter_count(from));
3241 out:
3242 return written;
3243 }
3244 EXPORT_SYMBOL(generic_file_direct_write);
3245
---
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