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| author | Konstantin Belousov <kib@FreeBSD.org> | 2022-12-28 18:13:01 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2022-12-29 20:55:39 +0000 |
| commit | 37b9fb169686e867987c8a1a9868f81137b9df2b (patch) | |
| tree | 254d1aa0bc05e70c725033de0baf1560b155b1f8 | |
| parent | 4ac8f4067096a9d4a00e41cd53bd5c4fa295fd15 (diff) | |
| download | src-37b9fb169686e867987c8a1a9868f81137b9df2b.tar.gz src-37b9fb169686e867987c8a1a9868f81137b9df2b.zip | |
Add descrip_check_write_mp() helper
... which verifies that given file table does not have file descriptors
referencing vnodes on the specified mount point. It is up to the caller
to ensure that the check is not racy.
Reviewed by: mckusick
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D37896
| -rw-r--r-- | sys/kern/kern_descrip.c | 23 | ||||
| -rw-r--r-- | sys/sys/filedesc.h | 2 |
2 files changed, 25 insertions, 0 deletions
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index 63a7f8b2a6d7..0be59e930dd4 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -4172,6 +4172,29 @@ mountcheckdirs(struct vnode *olddp, struct vnode *newdp) vrele(olddp); } +int +descrip_check_write_mp(struct filedesc *fdp, struct mount *mp) +{ + struct file *fp; + struct vnode *vp; + int error, i; + + error = 0; + FILEDESC_SLOCK(fdp); + FILEDESC_FOREACH_FP(fdp, i, fp) { + if (fp->f_type != DTYPE_VNODE || + (atomic_load_int(&fp->f_flag) & FWRITE) == 0) + continue; + vp = fp->f_vnode; + if (vp->v_mount == mp) { + error = EDEADLK; + break; + } + } + FILEDESC_SUNLOCK(fdp); + return (error); +} + struct filedesc_to_leader * filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader) diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h index 52bd3c97a9ac..ffea8d7e0195 100644 --- a/sys/sys/filedesc.h +++ b/sys/sys/filedesc.h @@ -225,6 +225,7 @@ enum { #define falloc(td, resultfp, resultfd, flags) \ falloc_caps(td, resultfp, resultfd, flags, NULL) +struct mount; struct thread; static __inline void @@ -241,6 +242,7 @@ void filecaps_free(struct filecaps *fcaps); int closef(struct file *fp, struct thread *td); void closef_nothread(struct file *fp); +int descrip_check_write_mp(struct filedesc *fdp, struct mount *mp); int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, int openerror, int *indxp); int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, |