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fifofs: fifo vnode might be relocked before VOP_OPEN() is called

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(cherry picked from commit 10db189649)
This commit is contained in:
Konstantin Belousov 2021-07-22 13:27:43 +03:00
parent a3c7e571c0
commit 2a56a5c2c2
1 changed files with 14 additions and 2 deletions
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16
sys/fs/fifofs/fifo_vnops.c
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@ -282,9 +282,21 @@ fifo_close(ap)
struct pipe *cpipe;
vp = ap->a_vp;
fip = vp->v_fifoinfo;
cpipe = fip->fi_pipe;
ASSERT_VOP_ELOCKED(vp, "fifo_close");
fip = vp->v_fifoinfo;
/*
* During open, it is possible that the fifo vnode is relocked
* after the vnode is instantiated but before VOP_OPEN() is
* done. For instance, vn_open_vnode() might need to upgrade
* vnode lock, or ffs_vput_pair() needs to unlock vp to sync
* dvp. In this case, reclaim can observe us with v_fifoinfo
* equal to NULL.
*/
if (fip == NULL)
return (0);
cpipe = fip->fi_pipe;
if (ap->a_fflag & FREAD) {
fip->fi_readers--;
if (fip->fi_readers == 0) {