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Use correct VFS locking rather than unconditionally grabbing Giant around

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namei() calls in kern_alternate_path().

Reviewed by:	csjp
MFC after:	1 week
This commit is contained in:
John Baldwin 2005-09-21 19:49:42 +00:00
parent 50757d2fce
commit e12560dd4b
1 changed files with 8 additions and 12 deletions
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20
sys/kern/vfs_lookup.c
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@ -972,9 +972,6 @@ kern_alternate_path(struct thread *td, const char *prefix, char *path,
goto keeporig;
}
/* XXX: VFS_LOCK_GIANT? */
mtx_lock(&Giant);
/*
* We know that there is a / somewhere in this pathname.
* Search backwards for it, to find the file's parent dir
@ -987,17 +984,17 @@ kern_alternate_path(struct thread *td, const char *prefix, char *path,
for (cp = &ptr[len] - 1; *cp != '/'; cp--);
*cp = '\0';
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td);
NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, buf, td);
error = namei(&nd);
*cp = '/';
if (error != 0)
goto nd_failed;
goto keeporig;
} else {
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td);
NDINIT(&nd, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, buf, td);
error = namei(&nd);
if (error != 0)
goto nd_failed;
goto keeporig;
/*
* We now compare the vnode of the prefix to the one
@ -1007,7 +1004,8 @@ kern_alternate_path(struct thread *td, const char *prefix, char *path,
* root directory and never finding it, because "/" resolves
* to the emulation root directory. This is expensive :-(
*/
NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, td);
NDINIT(&ndroot, LOOKUP, FOLLOW | MPSAFE, UIO_SYSSPACE, prefix,
td);
/* We shouldn't ever get an error from this namei(). */
error = namei(&ndroot);
@ -1017,15 +1015,13 @@ kern_alternate_path(struct thread *td, const char *prefix, char *path,
NDFREE(&ndroot, NDF_ONLY_PNBUF);
vrele(ndroot.ni_vp);
VFS_UNLOCK_GIANT(NDHASGIANT(&ndroot));
}
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
nd_failed:
/* XXX: VFS_UNLOCK_GIANT? */
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(NDHASGIANT(&nd));
keeporig:
/* If there was an error, use the original path name. */