linux.git/fs/ceph/snap.c, branch v3.13

ceph: use ceph_create_snap_context()

2013-05-02T04:20:09+00:00

Now that we have a library routine to create snap contexts, use it.

This is part of:
    http://tracker.ceph.com/issues/4857

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

ceph: define snap counts as u32 everywhere

2012-07-31T01:15:47+00:00

There are two structures in which a count of snapshots are
maintained:

    struct ceph_snap_context {
	...
        u32 num_snaps;
	...
    }
and
    struct ceph_snap_realm {
	...
        u32 num_prior_parent_snaps;   /*  had prior to parent_since */
	...
        u32 num_snaps;
	...
    }

These fields never take on negative values (e.g., to hold special
meaning), and so are really inherently unsigned.  Furthermore they
take their value from over-the-wire or on-disk formatted 32-bit
values.

So change their definition to have type u32, and change some spots
elsewhere in the code to account for this change.

Signed-off-by: Alex Elder 
Reviewed-by: Josh Durgin

introduce SIZE_MAX

2012-06-01T00:49:26+00:00

ULONG_MAX is often used to check for integer overflow when calculating
allocation size.  While ULONG_MAX happens to work on most systems, there
is no guarantee that `size_t' must be the same size as `long'.

This patch introduces SIZE_MAX, the maximum value of `size_t', to improve
portability and readability for allocation size validation.

Signed-off-by: Xi Wang 
Acked-by: Alex Elder 
Cc: David Airlie 
Cc: Pekka Enberg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ceph: fix overflow check in build_snap_context()

2012-03-22T15:47:45+00:00

The overflow check for a + n * b should be (n > (ULONG_MAX - a) / b),
rather than (n > ULONG_MAX / b - a).

Signed-off-by: Xi Wang 
Signed-off-by: Sage Weil

ceph: use i_ceph_lock instead of i_lock

2011-12-07T18:46:44+00:00

We have been using i_lock to protect all kinds of data structures in the
ceph_inode_info struct, including lists of inodes that we need to iterate
over while avoiding races with inode destruction.  That requires grabbing
a reference to the inode with the list lock protected, but igrab() now
takes i_lock to check the inode flags.

Changing the list lock ordering would be a painful process.

However, using a ceph-specific i_ceph_lock in the ceph inode instead of
i_lock is a simple mechanical change and avoids the ordering constraints
imposed by igrab().

Reported-by: Amon Ott 
Signed-off-by: Sage Weil

ceph: only queue capsnap if caps are dirty

2011-07-26T18:26:41+00:00

We used to go into this branch if i_wrbuffer_ref_head was non-zero.  This
was an ancient check from before we were careful about dealing with all
kinds of caps (and not just dirty pages).  It is cleaner to only queue a
capsnap if there is an actual dirty cap.  If we are racing with...
something...we will end up here with ci->i_wrbuffer_refs but no dirty
caps.

Reviewed-by: Yehuda Sadeh 
Signed-off-by: Sage Weil

ceph: fix snap writeback when racing with writes

2011-07-26T18:26:31+00:00

There are two problems that come up when we try to queue a capsnap while a
write is in progress:

 - The FILE_WR cap is held, but not yet dirty, so we may queue a capsnap
   with dirty == 0.  That will crash later in __ceph_flush_snaps().  Or
   on the FILE_WR cap if a write is in progress.
 - We may not have i_head_snapc set, which causes problems pretty quickly.
   Look to the snaprealm in this case.

Reviewed-by: Yehuda Sadeh 
Signed-off-by: Sage Weil

ceph: use ihold when we already have an inode ref

2011-06-08T04:34:11+00:00

We should use ihold whenever we already have a stable inode ref, even
when we aren't holding i_lock.  This avoids adding new and unnecessary
locking dependencies.

Signed-off-by: Sage Weil

ceph: fix list_add in ceph_put_snap_realm

2011-05-11T17:44:36+00:00

Signed-off-by: Henry C Chang 
Signed-off-by: Sage Weil

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi