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c63e56a4a6
overlayfs file open (ovl_maybe_lookup_lowerdata) and overlay file llseek take the ovl_inode_lock, without holding upper sb_writers. In case of nested lower overlay that uses same upper fs as this overlay, lockdep will warn about (possibly false positive) circular lock dependency when doing open/llseek of lower ovl file during copy up with our upper sb_writers held, because the locking ordering seems reverse to the locking order in ovl_copy_up_start(): - lower ovl_inode_lock - upper sb_writers Let the copy up "transaction" keeps an elevated mnt write count on upper mnt, but leaves taking upper sb_writers to lower level helpers only when they actually need it. This allows to avoid holding upper sb_writers during lower file open/llseek and prevents the lockdep warning. Minimizing the scope of upper sb_writers during copy up is also needed for fixing another possible deadlocks by a following patch. Signed-off-by: Amir Goldstein <amir73il@gmail.com> |
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| .. | ||
| copy_up.c | ||
| dir.c | ||
| export.c | ||
| file.c | ||
| inode.c | ||
| Kconfig | ||
| Makefile | ||
| namei.c | ||
| overlayfs.h | ||
| ovl_entry.h | ||
| params.c | ||
| params.h | ||
| readdir.c | ||
| super.c | ||
| util.c | ||