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| author | Mikulas Patocka <mpatocka@redhat.com> | 2020-09-05 15:13:02 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-09-05 20:00:05 +0300 |
| commit | b17164e258e3888d376a7434415013175d637377 (patch) | |
| tree | 21c52e660f8f8f53a47a52ddd5c974ae5796bb29 /fs | |
| parent | 1ef6ea0efe8e68d0299dad44c39dc6ad9e5d1f39 (diff) | |
| download | linux-b17164e258e3888d376a7434415013175d637377.tar.xz | |
xfs: don't update mtime on COW faults
When running in a dax mode, if the user maps a page with MAP_PRIVATE and
PROT_WRITE, the xfs filesystem would incorrectly update ctime and mtime
when the user hits a COW fault.
This breaks building of the Linux kernel. How to reproduce:
1. extract the Linux kernel tree on dax-mounted xfs filesystem
2. run make clean
3. run make -j12
4. run make -j12
at step 4, make would incorrectly rebuild the whole kernel (although it
was already built in step 3).
The reason for the breakage is that almost all object files depend on
objtool. When we run objtool, it takes COW page fault on its .data
section, and these faults will incorrectly update the timestamp of the
objtool binary. The updated timestamp causes make to rebuild the whole
tree.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_file.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index c31cd3be9fb2..a29f78a663ca 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1223,6 +1223,14 @@ __xfs_filemap_fault( return ret; } +static inline bool +xfs_is_write_fault( + struct vm_fault *vmf) +{ + return (vmf->flags & FAULT_FLAG_WRITE) && + (vmf->vma->vm_flags & VM_SHARED); +} + static vm_fault_t xfs_filemap_fault( struct vm_fault *vmf) @@ -1230,7 +1238,7 @@ xfs_filemap_fault( /* DAX can shortcut the normal fault path on write faults! */ return __xfs_filemap_fault(vmf, PE_SIZE_PTE, IS_DAX(file_inode(vmf->vma->vm_file)) && - (vmf->flags & FAULT_FLAG_WRITE)); + xfs_is_write_fault(vmf)); } static vm_fault_t @@ -1243,7 +1251,7 @@ xfs_filemap_huge_fault( /* DAX can shortcut the normal fault path on write faults! */ return __xfs_filemap_fault(vmf, pe_size, - (vmf->flags & FAULT_FLAG_WRITE)); + xfs_is_write_fault(vmf)); } static vm_fault_t |