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| author | Matthew Wilcox <willy@linux.intel.com> | 2015-09-08 14:59:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-08 15:35:28 -0700 |
| commit | 84c4e5e675408b6fb7d74eec7da9a4a5698b50af (patch) | |
| tree | 061bb263cd0d084e8e31fee41bf6e47c3397d7b6 | |
| parent | ae18d6dcf57b56b984ff27fd55b4e2caf5bfbd44 (diff) | |
| download | x86-pkeys-84c4e5e675408b6fb7d74eec7da9a4a5698b50af.tar.gz | |
dax: improve comment about truncate race
Jan Kara pointed out I should be more explicit here about the perils of
racing against truncate. The comment is mostly the same as for the PTE
case.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/dax.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/dax.c b/fs/dax.c index 2deed64b7eea7..c694117a70620 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -553,7 +553,12 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) goto fallback; - /* Guard against a race with truncate */ + /* + * If a truncate happened while we were allocating blocks, we may + * leave blocks allocated to the file that are beyond EOF. We can't + * take i_mutex here, so just leave them hanging; they'll be freed + * when the file is deleted. + */ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (pgoff >= size) { result = VM_FAULT_SIGBUS; |