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authorSage Weil <sage@newdream.net>2010-08-24 08:44:16 -0700
committerSage Weil <sage@newdream.net>2010-08-24 16:24:18 -0700
commit7d8cb26d7dcb911f110b7762bd5941e8f009d6c3 (patch)
tree2adf2f6303cc96ff14c951dc6966f68a0fc3cf25 /fs
parent07a27e226d1ed210d2d4218bd0642b40f5405c6a (diff)
downloadblackbird-op-linux-7d8cb26d7dcb911f110b7762bd5941e8f009d6c3.tar.gz
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ceph: maintain i_head_snapc when any caps are dirty, not just for data
We used to use i_head_snapc to keep track of which snapc the current epoch of dirty data was dirtied under. It is used by queue_cap_snap to set up the cap_snap. However, since we queue cap snaps for any dirty caps, not just for dirty file data, we need to keep a valid i_head_snapc anytime we have dirty|flushing caps. This fixes a NULL pointer deref in queue_cap_snap when writing back dirty caps without data (e.g., snaptest-authwb.sh). Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs')
-rw-r--r--fs/ceph/addr.c4
-rw-r--r--fs/ceph/caps.c20
-rw-r--r--fs/ceph/snap.c6
-rw-r--r--fs/ceph/super.h3
4 files changed, 26 insertions, 7 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 420d46974ec8..4cfce1ee31fa 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -87,7 +87,7 @@ static int ceph_set_page_dirty(struct page *page)
/* dirty the head */
spin_lock(&inode->i_lock);
- if (ci->i_wrbuffer_ref_head == 0)
+ if (ci->i_head_snapc == NULL)
ci->i_head_snapc = ceph_get_snap_context(snapc);
++ci->i_wrbuffer_ref_head;
if (ci->i_wrbuffer_ref == 0)
@@ -346,7 +346,7 @@ static struct ceph_snap_context *get_oldest_context(struct inode *inode,
break;
}
}
- if (!snapc && ci->i_head_snapc) {
+ if (!snapc && ci->i_wrbuffer_ref_head) {
snapc = ceph_get_snap_context(ci->i_head_snapc);
dout(" head snapc %p has %d dirty pages\n",
snapc, ci->i_wrbuffer_ref_head);
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index ba5bbf318fe1..a2069b6680ae 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1143,6 +1143,10 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
for (i = 0; i < CEPH_CAP_BITS; i++)
if (flushing & (1 << i))
ci->i_cap_flush_tid[i] = flush_tid;
+
+ follows = ci->i_head_snapc->seq;
+ } else {
+ follows = 0;
}
keep = cap->implemented;
@@ -1156,7 +1160,6 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
mtime = inode->i_mtime;
atime = inode->i_atime;
time_warp_seq = ci->i_time_warp_seq;
- follows = ci->i_snap_realm->cached_context->seq;
uid = inode->i_uid;
gid = inode->i_gid;
mode = inode->i_mode;
@@ -1332,7 +1335,11 @@ void __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
ceph_cap_string(was | mask));
ci->i_dirty_caps |= mask;
if (was == 0) {
- dout(" inode %p now dirty\n", &ci->vfs_inode);
+ if (!ci->i_head_snapc)
+ ci->i_head_snapc = ceph_get_snap_context(
+ ci->i_snap_realm->cached_context);
+ dout(" inode %p now dirty snapc %p\n", &ci->vfs_inode,
+ ci->i_head_snapc);
BUG_ON(!list_empty(&ci->i_dirty_item));
spin_lock(&mdsc->cap_dirty_lock);
list_add(&ci->i_dirty_item, &mdsc->cap_dirty);
@@ -2190,7 +2197,9 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
if (ci->i_head_snapc == snapc) {
ci->i_wrbuffer_ref_head -= nr;
- if (!ci->i_wrbuffer_ref_head) {
+ if (ci->i_wrbuffer_ref_head == 0 &&
+ ci->i_dirty_caps == 0 && ci->i_flushing_caps == 0) {
+ BUG_ON(!ci->i_head_snapc);
ceph_put_snap_context(ci->i_head_snapc);
ci->i_head_snapc = NULL;
}
@@ -2483,6 +2492,11 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
dout(" inode %p now clean\n", inode);
BUG_ON(!list_empty(&ci->i_dirty_item));
drop = 1;
+ if (ci->i_wrbuffer_ref_head == 0) {
+ BUG_ON(!ci->i_head_snapc);
+ ceph_put_snap_context(ci->i_head_snapc);
+ ci->i_head_snapc = NULL;
+ }
} else {
BUG_ON(list_empty(&ci->i_dirty_item));
}
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 6bdbf3ae7082..4868b9dcac5a 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -458,6 +458,8 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
CEPH_CAP_FILE_EXCL|CEPH_CAP_FILE_WR))) {
struct ceph_snap_context *snapc = ci->i_head_snapc;
+ dout("queue_cap_snap %p cap_snap %p queuing under %p\n", inode,
+ capsnap, snapc);
igrab(inode);
atomic_set(&capsnap->nref, 1);
@@ -489,7 +491,9 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
capsnap->dirty_pages = ci->i_wrbuffer_ref_head;
ci->i_wrbuffer_ref_head = 0;
capsnap->context = snapc;
- ci->i_head_snapc = NULL;
+ ci->i_head_snapc =
+ ceph_get_snap_context(ci->i_snap_realm->cached_context);
+ dout(" new snapc is %p\n", ci->i_head_snapc);
list_add_tail(&capsnap->ci_item, &ci->i_cap_snaps);
if (used & CEPH_CAP_FILE_WR) {
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b33929d8f287..c33897ae5725 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -344,7 +344,8 @@ struct ceph_inode_info {
unsigned i_cap_exporting_issued;
struct ceph_cap_reservation i_cap_migration_resv;
struct list_head i_cap_snaps; /* snapped state pending flush to mds */
- struct ceph_snap_context *i_head_snapc; /* set if wr_buffer_head > 0 */
+ struct ceph_snap_context *i_head_snapc; /* set if wr_buffer_head > 0 or
+ dirty|flushing caps */
unsigned i_snap_caps; /* cap bits for snapped files */
int i_nr_by_mode[CEPH_FILE_MODE_NUM]; /* open file counts */
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