search for: page_mkwrit

The fault code has been calling file_update_time after ->page_mkwrite after it drops the page lock, but this is annoying because this calls mark_inode_dirty which can fail in Btrfs, so we want to be able to do these updates in ->page_mkwrite so we can get an error back to the user. So get rid of the file_update_time calls in the fault code and push it into every...

...urs/days/weeks/months ... obviously the race window is big enough here. It affects many fs (ext4, xfs, ...) in different ways. I think ext4 is the most obvious because of the kernel log trace it leaves behind. Bottom line is for set_page_dirty to be safe you need the following: lock_page() page_mkwrite() set_pte_with_write() unlock_page() Now when loosing the write permission on the pte you will first get a mmu notifier callback so anyone that abide by mmu notifier is fine as long as they only write to the page if they found a pte with write as it means the above sequence did happen and...

...urs/days/weeks/months ... obviously the race window is big enough here. It affects many fs (ext4, xfs, ...) in different ways. I think ext4 is the most obvious because of the kernel log trace it leaves behind. Bottom line is for set_page_dirty to be safe you need the following: lock_page() page_mkwrite() set_pte_with_write() unlock_page() Now when loosing the write permission on the pte you will first get a mmu notifier callback so anyone that abide by mmu notifier is fine as long as they only write to the page if they found a pte with write as it means the above sequence did happen and...

...the > race window is big enough here. It affects many fs (ext4, xfs, ...) > in different ways. I think ext4 is the most obvious because of the > kernel log trace it leaves behind. > > Bottom line is for set_page_dirty to be safe you need the following: > lock_page() > page_mkwrite() > set_pte_with_write() > unlock_page() I also wondered why ext4 writepage doesn't recreate the bh if they got dropped by the VM and page->private is 0. I mean, page->index and page->mapping are still there, that's enough info for writepage itself to take a slow pa...

...wrt stable page writes. One workaround would be to use ext4 instead, or avoid the use of ext3.ko + DIF/DIX. Hopefully it doesn''t take long to sort out. Another thing I noticed is that there are several filesystems that call wait_on_page_writeback before returning VM_FAULT_LOCKED in their page_mkwrite delegates. It might be possible to convert some of these to wait_for_stable_pages unless there''s some other reason that we always want to wait for writeback. Finally, if a filesystem wants the VM to help it provide stable pages, it''s now possible to use the *_require_stable_pag...

...big enough here. It affects many fs (ext4, xfs, ...) >> in different ways. I think ext4 is the most obvious because of the >> kernel log trace it leaves behind. >> >> Bottom line is for set_page_dirty to be safe you need the following: >> lock_page() >> page_mkwrite() >> set_pte_with_write() >> unlock_page() > I also wondered why ext4 writepage doesn't recreate the bh if they got > dropped by the VM and page->private is 0. I mean, page->index and > page->mapping are still there, that's enough info for writepage...

...big enough here. It affects many fs (ext4, xfs, ...) >> in different ways. I think ext4 is the most obvious because of the >> kernel log trace it leaves behind. >> >> Bottom line is for set_page_dirty to be safe you need the following: >> lock_page() >> page_mkwrite() >> set_pte_with_write() >> unlock_page() > I also wondered why ext4 writepage doesn't recreate the bh if they got > dropped by the VM and page->private is 0. I mean, page->index and > page->mapping are still there, that's enough info for writepage...

On Thu, Mar 07, 2019 at 10:34:39AM -0500, Michael S. Tsirkin wrote: > On Thu, Mar 07, 2019 at 10:45:57AM +0800, Jason Wang wrote: > > > > On 2019/3/7 ??12:31, Michael S. Tsirkin wrote: > > > > +static void vhost_set_vmap_dirty(struct vhost_vmap *used) > > > > +{ > > > > + int i; > > > > + > > > > + for (i = 0; i <

...int partial = 0; > @@ -2151,7 +2151,6 @@ int block_commit_write(struct page *page, unsigned int from, unsigned int to) > */ > if (!partial) > SetPageUptodate(page); > - return 0; > } > EXPORT_SYMBOL(block_commit_write); > > @@ -2577,11 +2576,11 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > end = PAGE_SIZE; > > ret = __block_write_begin(page, 0, end, get_block); > - if (!ret) > - ret = block_commit_write(page, 0, end); > - > - if (unlikely(ret < 0)) > + if (unlikely(ret)) > goto out_unlock; &...

Here is the original set of fixes, split out into 14 individual ones. In addition to splitting them out, I also changed the ones that were HAS_* to NO_* as requested. The last two patches are needed to build on openSUSE 10.3 which is based on 2.6.22. I used it as a sanity check and found those failures. -Jeff -- Jeff Mahoney SUSE Labs

...t_write(struct page *page, unsigned from, unsigned to) +void block_commit_write(struct page *page, unsigned from, unsigned to) { struct folio *folio = page_folio(page); __block_commit_write(folio, from, to); - return 0; } EXPORT_SYMBOL(block_commit_write); @@ -2647,11 +2645,11 @@ int block_page_mkwrite(struct vm_area_st end = size - folio_pos(folio); ret = __block_write_begin_int(folio, 0, end, get_block, NULL); - if (!ret) - ret = __block_commit_write(folio, 0, end); + if (unlikely(ret)) + goto out_unlock; + + __block_commit_write(folio, 0, end); - if (unlikely(ret < 0)) - goto...

Changelog: v1--v2: 1. Re-order patches to avoid breaking compilation. Bean Huo (5): fs/buffer: clean up block_commit_write ext4: No need to check return value of block_commit_write() fs/ocfs2: No need to check return value of block_commit_write() udf: No need to check return value of block_commit_write() fs/buffer.c: convert block_commit_write to return void fs/buffer.c

Found 15 patches (out of 162) that appeared relevant to ocfs2 1.4. Please review. Sunil

*** BLURB HERE *** Bean Huo (5): fs/buffer: clean up block_commit_write fs/buffer.c: convert block_commit_write to return void ext4: No need to check return value of block_commit_write() fs/ocfs2: No need to check return value of block_commit_write() udf: No need to check return value of block_commit_write() fs/buffer.c | 24 +++++++-----------------

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. I started with the Xen version at http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/ca05cf1a9bdc Differences to that Xen version, for those who care: * Rewritten on top of fb deferred

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. I started with the Xen version at http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/ca05cf1a9bdc Differences to that Xen version, for those who care: * Rewritten on top of fb deferred

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. I started with the Xen version at http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/ca05cf1a9bdc Differences to that Xen version, for those who care: * Rewritten on top of fb deferred

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. Differences since last post: * Required patch fixing 32-on-64 xen-blkfront included. * Cleanup when xenkbd_probe() fails fixed. * Don't store event channel in device info. I started

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. Differences since last post: * Required patch fixing 32-on-64 xen-blkfront included. * Cleanup when xenkbd_probe() fails fixed. * Don't store event channel in device info. I started

This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. Differences since last post: * Required patch fixing 32-on-64 xen-blkfront included. * Cleanup when xenkbd_probe() fails fixed. * Don't store event channel in device info. I started