linux-stable.git/fs/ceph/snap.c, branch v4.4.263

ceph: fix ci->i_head_snapc leak

2019-05-16T17:44:43+00:00

commit 37659182bff1eeaaeadcfc8f853c6d2b6dbc3f47 upstream.

We missed two places that i_wrbuffer_ref_head, i_wr_ref, i_dirty_caps
and i_flushing_caps may change. When they are all zeros, we should free
i_head_snapc.

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/38224
Reported-and-tested-by: Luis Henriques 
Signed-off-by: "Yan, Zheng" 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

ceph: avoid repeatedly adding inode to mdsc->snap_flush_list

2019-03-23T07:44:15+00:00

commit 04242ff3ac0abbaa4362f97781dac268e6c3541a upstream.

Otherwise, mdsc->snap_flush_list may get corrupted.

Cc: stable@vger.kernel.org
Signed-off-by: "Yan, Zheng" 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov 
Signed-off-by: Greg Kroah-Hartman

ceph: fix queuing inode to mdsdir's snaprealm

2015-09-08T20:14:29+00:00

During MDS failovers, MClientSnap message may cause kclient to move
some inodes from root directory's snaprealm to mdsdir's snaprealm
and queue snapshots for these inodes. For a FS has never created any
snapshot, both root directory's snaprealm and mdsdir's snaprealm
share the same snapshot contexts (both are ceph_empty_snapc). This
confuses ceph_put_wrbuffer_cap_refs(), make it unable to distinguish
snapshot buffers from head buffers.

The fix is do not use ceph_empty_snapc as snaprealm's cached context.

Signed-off-by: Yan, Zheng

ceph: make sure syncfs flushes all cap snaps

2015-06-25T08:49:29+00:00

Signed-off-by: Yan, Zheng

ceph: avoid sending unnessesary FLUSHSNAP message

2015-06-25T08:49:28+00:00

when a snap notification contains no new snapshot, we can avoid
sending FLUSHSNAP message to MDS. But we still need to create
cap_snap in some case because it's required by write path and
page writeback path

Signed-off-by: Yan, Zheng

ceph: set i_head_snapc when getting CEPH_CAP_FILE_WR reference

2015-06-25T08:49:28+00:00

In most cases that snap context is needed, we are holding
reference of CEPH_CAP_FILE_WR. So we can set ceph inode's
i_head_snapc when getting the CEPH_CAP_FILE_WR reference,
and make codes get snap context from i_head_snapc. This makes
the code simpler.

Another benefit of this change is that we can handle snap
notification more elegantly. Especially when snap context
is updated while someone else is doing write. The old queue
cap_snap code may set cap_snap's context to ether the old
context or the new snap context, depending on if i_head_snapc
is set. The new queue capp_snap code always set cap_snap's
context to the old snap context.

Signed-off-by: Yan, Zheng

ceph: use empty snap context for uninline_data and get_pool_perm

2015-06-25T08:49:28+00:00

Cached_context in ceph_snap_realm is directly accessed by
uninline_data() and get_pool_perm(). This is racy in theory.
both uninline_data() and get_pool_perm() do not modify existing
object, they only create new object. So we can pass the empty
snap context to them.  Unlike cached_context in ceph_snap_realm,
we do not need to protect the empty snap context.

Signed-off-by: Yan, Zheng

ceph: improve reference tracking for snaprealm

2015-02-19T10:31:38+00:00

When snaprealm is created, its initial reference count is zero.
But in some rare cases, the newly created snaprealm is not referenced
by anyone. This causes snaprealm with zero reference count not freed.

The fix is set reference count of newly snaprealm to 1. The reference
is return the function who requests to create the snaprealm. When the
function finishes its job, it releases the reference.

Signed-off-by: Yan, Zheng

ceph: flush inline version

2014-12-17T17:09:53+00:00

After converting inline data to normal data, client need to flush
the new i_inline_version (CEPH_INLINE_NONE) to MDS. This commit makes
cap messages (sent to MDS) contain inline_version and inline_data.
Client always converts inline data to normal data before data write,
so the inline data length part is always zero.

Signed-off-by: Yan, Zheng

ceph: introduce global empty snap context

2014-12-17T17:09:51+00:00

Current snaphost code does not properly handle moving inode from one
empty snap realm to another empty snap realm. After changing inode's
snap realm, some dirty pages' snap context can be not equal to inode's
i_head_snap. This can trigger BUG() in ceph_put_wrbuffer_cap_refs()

The fix is introduce a global empty snap context for all empty snap
realm. This avoids triggering the BUG() for filesystem with no snapshot.

Fixes: http://tracker.ceph.com/issues/9928

Signed-off-by: Yan, Zheng 
Reviewed-by: Ilya Dryomov