From: Amir Goldstein <amir73il@gmail.com> mainline inclusion from mainline-v6.7-rc1 commit d08d3b3c2caf6c482703bbc5efaa7b9ae95dea20 category: feature bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBHLU4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- ovl_get_write_access() gets write access to upper mnt without taking freeze protection on upper sb and ovl_start_write() only takes freeze protection on upper sb. These helpers will be used to breakup the large ovl_want_write() scope during copy up into finer grained freeze protection scopes. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/overlayfs/overlayfs.h | 4 ++++ fs/overlayfs/util.c | 26 ++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 981967e507b3..95c4bc67dbe3 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -406,6 +406,10 @@ static inline int ovl_do_getattr(const struct path *path, struct kstat *stat, } /* util.c */ +int ovl_get_write_access(struct dentry *dentry); +void ovl_put_write_access(struct dentry *dentry); +void ovl_start_write(struct dentry *dentry); +void ovl_end_write(struct dentry *dentry); int ovl_want_write(struct dentry *dentry); void ovl_drop_write(struct dentry *dentry); struct dentry *ovl_workdir(struct dentry *dentry); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 3bc4a6bc582e..f543956d23b4 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -17,12 +17,38 @@ #include <linux/ratelimit.h> #include "overlayfs.h" +/* Get write access to upper mnt - may fail if upper sb was remounted ro */ +int ovl_get_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + return mnt_get_write_access(ovl_upper_mnt(ofs)); +} + +/* Get write access to upper sb - may block if upper sb is frozen */ +void ovl_start_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_start_write(ovl_upper_mnt(ofs)->mnt_sb); +} + int ovl_want_write(struct dentry *dentry) { struct ovl_fs *ofs = OVL_FS(dentry->d_sb); return mnt_want_write(ovl_upper_mnt(ofs)); } +void ovl_put_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + mnt_put_write_access(ovl_upper_mnt(ofs)); +} + +void ovl_end_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_end_write(ovl_upper_mnt(ofs)->mnt_sb); +} + void ovl_drop_write(struct dentry *dentry) { struct ovl_fs *ofs = OVL_FS(dentry->d_sb); -- 2.39.2