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ceph: set dn offset when spliced

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We want to assign an offset when the dentry goes from null to linked, which
is always done by splice_dentry().  Notably, we should NOT assign an
offset when a dentry is first created and is still null.

BUG if we try to splice a non-null dentry (we shouldn't).

Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil
2010-05-03 22:08:02 -07:00
parent 1b7facc41b
commit 1cd3935bed
2 changed files with 56 additions and 52 deletions
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95
fs/ceph/inode.c
View File

@ -803,50 +803,6 @@ out_unlock:
return;
}
/*
* splice a dentry to an inode.
* caller must hold directory i_mutex for this to be safe.
*
* we will only rehash the resulting dentry if @prehash is
* true; @prehash will be set to false (for the benefit of
* the caller) if we fail.
*/
static struct dentry *splice_dentry(struct dentry *dn, struct inode *in,
bool *prehash)
{
struct dentry *realdn;
/* dn must be unhashed */
if (!d_unhashed(dn))
d_drop(dn);
realdn = d_materialise_unique(dn, in);
if (IS_ERR(realdn)) {
pr_err("splice_dentry error %p inode %p ino %llx.%llx\n",
dn, in, ceph_vinop(in));
if (prehash)
*prehash = false; /* don't rehash on error */
dn = realdn; /* note realdn contains the error */
goto out;
} else if (realdn) {
dout("dn %p (%d) spliced with %p (%d) "
"inode %p ino %llx.%llx\n",
dn, atomic_read(&dn->d_count),
realdn, atomic_read(&realdn->d_count),
realdn->d_inode, ceph_vinop(realdn->d_inode));
dput(dn);
dn = realdn;
} else {
BUG_ON(!ceph_dentry(dn));
dout("dn %p attached to %p ino %llx.%llx\n",
dn, dn->d_inode, ceph_vinop(dn->d_inode));
}
if ((!prehash || *prehash) && d_unhashed(dn))
d_rehash(dn);
out:
return dn;
}
/*
* Set dentry's directory position based on the current dir's max, and
* order it in d_subdirs, so that dcache_readdir behaves.
@ -878,6 +834,52 @@ static void ceph_set_dentry_offset(struct dentry *dn)
spin_unlock(&dcache_lock);
}
/*
* splice a dentry to an inode.
* caller must hold directory i_mutex for this to be safe.
*
* we will only rehash the resulting dentry if @prehash is
* true; @prehash will be set to false (for the benefit of
* the caller) if we fail.
*/
static struct dentry *splice_dentry(struct dentry *dn, struct inode *in,
bool *prehash)
{
struct dentry *realdn;
BUG_ON(dn->d_inode);
/* dn must be unhashed */
if (!d_unhashed(dn))
d_drop(dn);
realdn = d_materialise_unique(dn, in);
if (IS_ERR(realdn)) {
pr_err("splice_dentry error %p inode %p ino %llx.%llx\n",
dn, in, ceph_vinop(in));
if (prehash)
*prehash = false; /* don't rehash on error */
dn = realdn; /* note realdn contains the error */
goto out;
} else if (realdn) {
dout("dn %p (%d) spliced with %p (%d) "
"inode %p ino %llx.%llx\n",
dn, atomic_read(&dn->d_count),
realdn, atomic_read(&realdn->d_count),
realdn->d_inode, ceph_vinop(realdn->d_inode));
dput(dn);
dn = realdn;
} else {
BUG_ON(!ceph_dentry(dn));
dout("dn %p attached to %p ino %llx.%llx\n",
dn, dn->d_inode, ceph_vinop(dn->d_inode));
}
if ((!prehash || *prehash) && d_unhashed(dn))
d_rehash(dn);
ceph_set_dentry_offset(dn);
out:
return dn;
}
/*
* Incorporate results into the local cache. This is either just
* one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
@ -1030,6 +1032,9 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
ceph_invalidate_dentry_lease(dn);
/* take overwritten dentry's readdir offset */
dout("dn %p gets %p offset %lld (old offset %lld)\n",
req->r_old_dentry, dn, ceph_dentry(dn)->offset,
ceph_dentry(req->r_old_dentry)->offset);
ceph_dentry(req->r_old_dentry)->offset =
ceph_dentry(dn)->offset;
@ -1074,7 +1079,6 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
goto done;
}
req->r_dentry = dn; /* may have spliced */
ceph_set_dentry_offset(dn);
igrab(in);
} else if (ceph_ino(in) == vino.ino &&
ceph_snap(in) == vino.snap) {
@ -1117,7 +1121,6 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
err = PTR_ERR(dn);
goto done;
}
ceph_set_dentry_offset(dn);
req->r_dentry = dn; /* may have spliced */
igrab(in);
rinfo->head->is_dentry = 1; /* fool notrace handlers */