08 Dec, 2011

1 commit

  • 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

    Sage Weil
     

27 Jul, 2011

2 commits

  • 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

    Sage Weil
     
  • 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

    Sage Weil
     

08 Jun, 2011

1 commit


12 May, 2011

1 commit


31 Mar, 2011

1 commit


29 Mar, 2011

1 commit

  • Fix the incorrect use of igrab() inside the i_lock in NFS and Ceph‥

    If we are already holding the i_lock, we have a reference to the
    inode so we can safely use ihold() to gain an extra reference. This
    avoids hangs due to lock recursion on the i_lock now that the
    inode_lock is gone and igrab() uses the i_lock itself.

    Signed-off-by: Dave Chinner
    Cc: Al Viro
    Cc: linux-fsdevel@vger.kernel.org
    Cc: Ryan Mallon
    Signed-off-by: Linus Torvalds

    Dave Chinner
     

05 Feb, 2011

1 commit

  • We were forming a dirty list, and then queueing cap_snaps for each realm
    _and_ its children, regardless of whether the children were already in the
    dirty list. This meant we did it twice for some realms. Which in turn
    meant we corrupted mdsc->snap_flush_list when the cap_snap was re-added to
    the list it was already on, and could trigger an infinite loop.

    We were also using recursion to do reach all the children, a no-no when
    stack is limited.

    Instead, (re)queue any children on the dirty list, avoiding processing
    anything twice and avoiding any recursion.

    Signed-off-by: Sage Weil

    Sage Weil
     

21 Oct, 2010

1 commit

  • This factors out protocol and low-level storage parts of ceph into a
    separate libceph module living in net/ceph and include/linux/ceph. This
    is mostly a matter of moving files around. However, a few key pieces
    of the interface change as well:

    - ceph_client becomes ceph_fs_client and ceph_client, where the latter
    captures the mon and osd clients, and the fs_client gets the mds client
    and file system specific pieces.
    - Mount option parsing and debugfs setup is correspondingly broken into
    two pieces.
    - The mon client gets a generic handler callback for otherwise unknown
    messages (mds map, in this case).
    - The basic supported/required feature bits can be expanded (and are by
    ceph_fs_client).

    No functional change, aside from some subtle error handling cases that got
    cleaned up in the refactoring process.

    Signed-off-by: Sage Weil

    Yehuda Sadeh
     

17 Sep, 2010

2 commits

  • Sending multiple flushsnap messages is problematic because we ignore
    the response if the tid doesn't match, and the server may only respond to
    each one once. It's also a waste.

    So, skip cap_snaps that are already on the flushing list, unless the caller
    tells us to resend (because we are reconnecting).

    Signed-off-by: Sage Weil

    Sage Weil
     
  • The cap_snap creation/queueing relies on both the current i_head_snapc
    _and_ the i_snap_realm pointers being correct, so that the new cap_snap
    can properly reference the old context and the new i_head_snapc can be
    updated to reference the new snaprealm's context. To fix this, we:

    - move inodes completely to the new (split) realm so that i_snap_realm
    is correct, and
    - generate the new snapc's _before_ queueing the cap_snaps in
    ceph_update_snap_trace().

    Signed-off-by: Sage Weil

    Sage Weil
     

15 Sep, 2010

1 commit


25 Aug, 2010

1 commit

  • 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 Weil
     

23 Aug, 2010

2 commits

  • When a realm is updated, we need to queue writeback on inodes in that
    realm _and_ its children. Otherwise, if the inode gets cowed on the
    server, we can get a hang later due to out-of-sync cap/snap state.

    Signed-off-by: Sage Weil

    Sage Weil
     
  • When we snapshot dirty metadata that needs to be written back to the MDS,
    include dirty xattr metadata. Make the capsnap reference the encoded
    xattr blob so that it will be written back in the FLUSHSNAP op.

    Also fix the capsnap creation guard to include dirty auth or file bits,
    not just tests specific to dirty file data or file writes in progress
    (this fixes auth metadata writeback).

    Signed-off-by: Sage Weil

    Sage Weil
     

18 May, 2010

1 commit

  • ceph_sb_to_client and ceph_client are really identical, we need to dump
    one; while function ceph_client is confusing with "struct ceph_client",
    ceph_sb_to_client's definition is more clear; so we'd better switch all
    call to ceph_sb_to_client.

    -static inline struct ceph_client *ceph_client(struct super_block *sb)
    -{
    - return sb->s_fs_info;
    -}

    Signed-off-by: Cheng Renquan
    Signed-off-by: Sage Weil

    Cheng Renquan
     

04 May, 2010

1 commit

  • The snap realm split was checking i_snap_realm, not the list_head, to
    determine if an inode belonged in the new realm. The check always failed,
    which meant we always moved the inode, corrupting the old realm's list and
    causing various crashes.

    Also wait to release old realm reference to avoid possibility of use after
    free.

    Signed-off-by: Sage Weil

    Sage Weil
     

15 Apr, 2010

1 commit

  • * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
    ceph: use separate class for ceph sockets' sk_lock
    ceph: reserve one more caps space when doing readdir
    ceph: queue_cap_snap should always queue dirty context
    ceph: fix dentry reference leak in dcache readdir
    ceph: decode v5 of osdmap (pool names) [protocol change]
    ceph: fix ack counter reset on connection reset
    ceph: fix leaked inode ref due to snap metadata writeback race
    ceph: fix snap context reference leaks
    ceph: allow writeback of snapped pages older than 'oldest' snapc
    ceph: fix dentry rehashing on virtual .snap dir

    Linus Torvalds
     

14 Apr, 2010

1 commit

  • This simplifies the calling convention, and fixes a bug where we queue a
    capsnap with a context other than i_head_snapc (the one that matches the
    dirty pages). The result was a BUG at fs/ceph/caps.c:2178 on writeback
    completion when a capsnap matching the writeback snapc could not be found.

    Signed-off-by: Sage Weil

    Sage Weil
     

02 Apr, 2010

1 commit

  • We create a ceph_cap_snap if there is dirty cap metadata (for writeback to
    mds) OR dirty pages (for writeback to osd). It is thus possible that the
    metadata has been written back to the MDS but the OSD data has not when
    the cap_snap is created. This results in a cap_snap with dirty(caps) == 0.
    The problem is that cap writeback to the MDS isn't necessary, and a
    FLUSHSNAP cap op gets no ack from the MDS. This leaves the cap_snap
    attached to the inode along with its inode reference.

    Fix the problem by dropping the cap_snap if it becomes 'complete' (all
    pages written out) and dirty(caps) == 0 in ceph_put_wrbuffer_cap_refs().

    Also, BUG() in __ceph_flush_snaps() if we encounter a cap_snap with
    dirty(caps) == 0.

    Signed-off-by: Sage Weil

    Sage Weil
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

23 Mar, 2010

1 commit

  • We were rebuilding the snap context when it was not necessary
    (i.e. when the realm seq hadn't changed _and_ the parent seq
    was still older), which caused page snapc pointers to not match
    the realm's snapc pointer (even though the snap context itself
    was identical). This confused begin_write and put it into an
    endless loop.

    The correct logic is: rebuild snapc if _my_ realm seq changed, or
    if my parent realm's seq is newer than mine (and thus mine needs
    to be rebuilt too).

    Signed-off-by: Sage Weil

    Sage Weil
     

21 Mar, 2010

1 commit


24 Feb, 2010

1 commit


17 Feb, 2010

1 commit


22 Dec, 2009

1 commit


22 Nov, 2009

1 commit


07 Oct, 2009

1 commit

  • Ceph snapshots rely on client cooperation in determining which
    operations apply to which snapshots, and appropriately flushing
    snapshotted data and metadata back to the OSD and MDS clusters.
    Because snapshots apply to subtrees of the file hierarchy and can be
    created at any time, there is a fair bit of bookkeeping required to
    make this work.

    Portions of the hierarchy that belong to the same set of snapshots
    are described by a single 'snap realm.' A 'snap context' describes
    the set of snapshots that exist for a given file or directory.

    Signed-off-by: Sage Weil

    Sage Weil