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2012-04-05qed: remove incoming live migration blockerBenoƮt Canet
Signed-off-by: Benoit Canet <benoit.canet@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-09qed: add .bdrv_co_write_zeroes() supportStefan Hajnoczi
Zero writes are a dedicated interface for writing regions of zeroes into the image file. If clusters are not yet allocated it is possible to use an efficient metadata representation which keeps the image file compact and does not store individual zero bytes. Implementing this for the QED image format is fairly straightforward. The only issue is that when a zero write touches an existing cluster we have to allocate a bounce buffer and perform a regular write. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-02-09qed: replace is_write with flags fieldStefan Hajnoczi
Per-request attributes like read/write are currently implemented as bool fields in the QEDAIOCB struct. This becomes unwiedly as the number of attributes grows. For example, the qed_aio_setup() function would have to take multiple bool arguments and at call sites it would be hard to distinguish the meaning of each bool. Instead use a flags field with bitmask constants. This will be used when zero write support is added. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-21qed: add migration blocker (v2)Anthony Liguori
Now when you try to migrate with qed, you get: (qemu) migrate tcp:localhost:1025 Block format 'qed' used by device 'ide0-hd0' does not support feature 'live migration' (qemu) Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-05-18qed: Periodically flush and clear need check bitStefan Hajnoczi
One strategy to limit the startup delay of consistency check when opening image files is to ensure that the file is marked dirty for as little time as possible. QED currently marks the image dirty when the first allocating write request is issued and clears the dirty bit again when the image is cleanly closed. In practice that means the image is marked dirty for most of a guest's lifetime and prone to being in a dirty state upon crash or power failure. It is safe to clear the dirty bit after all allocating write requests have completed and a flush has been performed. This patch adds a timer after the last allocating write request completes. When the timer fires it will flush and then clear the dirty bit. The timer is set to 5 seconds and is cancelled upon arrival of a new allocating write request. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-04-27qed: Fix consistency check on 32-bit hostsStefan Hajnoczi
The qed_bytes_to_clusters() function is normally used with size_t lengths. Consistency check used it with file size length and therefore failed on 32-bit hosts when the image file is 4 GB or more. Make qed_bytes_to_clusters() explicitly 64-bit and update consistency check to keep 64-bit cluster counts. Reported-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-04-13qed: Add support for zero clustersAnthony Liguori
Zero clusters are similar to unallocated clusters except instead of reading their value from a backing file when one is available, the cluster is always read as zero. This implements read support only. At this stage, QED will never write a zero cluster. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17qed: Consistency check supportStefan Hajnoczi
This patch adds support for the qemu-img check command. It also introduces a dirty bit in the qed header to mark modified images as needing a check. This bit is cleared when the image file is closed cleanly. If an image file is opened and it has the dirty bit set, a consistency check will run and try to fix corrupted table offsets. These corruptions may occur if there is power loss while an allocating write is performed. Once the image is fixed it opens as normal again. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17qed: Read/write supportStefan Hajnoczi
This patch implements the read/write state machine. Operations are fully asynchronous and multiple operations may be active at any time. Allocating writes lock tables to ensure metadata updates do not interfere with each other. If two allocating writes need to update the same L2 table they will run sequentially. If two allocating writes need to update different L2 tables they will run in parallel. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17qed: Table, L2 cache, and cluster functionsStefan Hajnoczi
This patch adds code to look up data cluster offsets in the image via the L1/L2 tables. The L2 tables are writethrough cached in memory for performance (each read/write requires a lookup so it is essential to cache the tables). With cluster lookup code in place it is possible to implement bdrv_is_allocated() to query the number of contiguous allocated/unallocated clusters. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-17qed: Add QEMU Enhanced Disk image formatStefan Hajnoczi
This patch introduces the qed on-disk layout and implements image creation. Later patches add read/write and other functionality. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>