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Alex Elder 3e83b65bb9 rbd: don't create sysfs entries for non-mapped snapshots 
When an rbd image gets mapped a device entry gets created for it
under /sys/bus/rbd/devices/<id>/.  Inside that directory there are
sysfs files that contain information about the image: its size,
feature bits, major device number, and so on.

Additionally, if that image has any snapshots, a device entry gets
created for each of those as a "child" of the mapped device.  Each
of these is a subdirectory of the mapped device, and each directory
contains a few files with information about the snapshot (its
snapshot id, size, and feature mask).

There is no clear benefit to having those device entries for the
snapshots.  The information provided via sysfs of of little real
value--and all of it is available via rbd CLI commands.  If we
still wanted to see the kernel's view of this information it could
be done much more simply by including it in a single sysfs file for
the mapped image.

But there *is* a clear cost to supporting them.  Every time a snapshot
context changes, these entries need to be updated (deleted snapshots
removed, new snapshots created).  The rbd driver is notified of
changes to the snapshot context via callbacks from an osd, and care
must be taken to coordinate removal of snapshot data structures
with the possibility of one these notifications occurring.

Things would be considerably simpler if we just didn't have to
maintain device entries for the snapshots.

So get rid of them.

The ability to map a snapshot of an rbd image will remain; the only
thing lost will be the ability to query these sysfs directories for
information about snapshots of mapped images.

This resolves:
    http://tracker.ceph.com/issues/4796

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
2013-05-01 21:19:25 -07:00
..
ABI rbd: don't create sysfs entries for non-mapped snapshots 2013-05-01 21:19:25 -07:00
accounting doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c 2012-11-26 14:22:21 +01:00
acpi ACPI / Documentation: refer to correct file for acpi_platform_device_ids[] table 2013-02-13 13:43:02 +01:00
aoe aoe: allow user to disable target failure timeout 2012-12-17 17:15:25 -08:00
arm fbdev changes for 3.8: 2012-12-15 13:03:48 -08:00
arm64 arm64: Add simple earlyprintk support 2013-01-22 17:51:01 +00:00
auxdisplay
backlight backlight: lp855x_bl: support new LP8557 device 2013-02-21 17:22:25 -08:00
blackfin
block cfq-iosched: enable full blkcg hierarchy support 2013-01-09 08:05:11 -08:00
blockdev nbd: update documentation and link to mailinglist 2013-02-27 19:10:22 -08:00
bus-devices ARM: OMAP2+: gpmc: generic timing calculation 2012-11-09 18:07:11 +05:30
cdrom
cgroups Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block 2013-02-28 12:52:24 -08:00
connector
console
cpu-freq cpufreq: Update Documentation for cpus and related_cpus 2013-02-02 00:01:16 +01:00
cpuidle Honor state disabling in the cpuidle ladder governor 2012-09-04 01:35:44 +02:00
cris
crypto KEYS: Document asymmetric key type 2012-10-08 13:50:12 +10:30
development-process
device-mapper md updates for 3.9 2013-03-05 17:22:08 -08:00
devicetree This is the first batch of MFD fixes for 3.9. 2013-03-15 17:34:01 -07:00
DocBook tty: Documentation: fix a path in a DocBook template 2013-04-03 11:45:38 -07:00
driver-model lib: devres: Introduce devm_ioremap_resource() 2013-01-22 09:41:43 -08:00
dvb [media] get_dvb_firmware: Fix the location of firmware for Terratec HTC 2013-01-01 11:18:26 -02:00
early-userspace
EDID drm: Load EDID: Explain better how to write your own EDID firmware 2013-01-20 19:22:19 +10:00
extcon
fault-injection doc: fix quite a few typos within Documentation 2012-11-19 14:28:24 +01:00
fb
filesystems Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
firmware_class firmware loader: document firmware cache mechanism 2012-11-14 15:07:18 -08:00
frv
hid HID: remove x bit from sensor doc 2012-12-14 08:48:59 +01:00
hwmon hwmon: (lm75) Fix tcn75 prefix 2013-03-18 21:19:49 +01:00
i2c i2c: Fix my e-mail address in drivers and documentation 2013-03-22 11:18:34 +01:00
i2o
ia64 doc: aliasing-test: close fd on write error 2012-09-01 09:57:10 -07:00
ide
infiniband IB/ipoib: Add rtnl_link_ops support 2012-09-20 16:49:17 -04:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-03-11 07:49:37 -07:00
ioctl wanrouter: completely decouple obsolete code from kernel. 2013-01-31 19:20:33 -05:00
isdn
ja_JP
kbuild Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2013-02-27 12:28:30 -08:00
kdump
ko_KR
laptops Documentation/laptops: remove depends on CONFIG_EXPERIMENTAL 2013-01-21 14:52:42 -08:00
leds Documentation: leds: update LP55xx family devices 2013-02-06 15:59:30 -08:00
m68k
make
memory-devices
metag metag: Basic documentation 2013-03-02 20:09:50 +00:00
mips
misc-devices doc: fix quite a few typos within Documentation 2012-11-19 14:28:24 +01:00
mmc mmc: core: Extend sysfs to ext_csd parameters for RPMB support 2012-12-06 13:54:48 -05:00
mn10300
mtd
namespaces userns: Recommend use of memory control groups. 2013-01-26 22:20:06 -08:00
netlabel
networking ipvs: add backup_only flag to avoid loops 2013-03-19 21:21:51 +09:00
nfc NFC: Update pn544 documentation 2013-01-10 01:27:46 +01:00
parisc
PCI PCI/MSI: Enable multiple MSIs with pci_enable_msi_block_auto() 2013-01-24 17:25:13 +01:00
pcmcia
power PM / OPP: improve introductory documentation 2013-03-04 14:23:11 +01:00
powerpc powerpc: Documentation for transactional memory on powerpc 2013-02-15 17:02:25 +11:00
pps
prctl seccomp: Make syscall skipping and nr changes more consistent 2012-10-02 21:14:29 +10:00
pti
ptp
rapidio
RCU Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD 2012-11-16 09:59:58 -08:00
s390
scheduler sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW 2012-09-13 16:52:04 +02:00
scsi [SCSI] qla2xxx: Update copyright dates information in LICENSE.qla2xxx file. 2013-04-06 11:31:30 +01:00
security Documentation: fix Documentation/security/00-INDEX 2012-12-17 17:15:22 -08:00
serial tty: Update serial core API documentation 2013-01-15 21:57:44 -08:00
sh
sound Revert "ALSA: hda - Allow power_save_controller option override DCAPS" 2013-04-04 15:35:39 +02:00
spi Documentation: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
sysctl Documentation/sysctl/kernel.txt: document /proc/sys/shmall 2013-01-04 16:11:46 -08:00
target target: Simplify fabric sense data length handling 2012-09-17 17:12:58 -07:00
thermal Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2013-02-28 19:48:26 -08:00
timers
trace Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-03-11 07:54:29 -07:00
usb USB: report submission of active URBs 2012-11-11 18:10:46 -08:00
vDSO
video4linux [media] radio-si470x doc: add info about v4l2-ctl and sox+alsa 2013-02-13 17:33:20 -02:00
virtual Merge tag 'kvm-3.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2013-02-24 13:07:18 -08:00
vm ksm: add some comments 2013-02-23 17:50:23 -08:00
w1 w1: w1_therm: Add force-pullup option for "broken" sensors 2013-02-18 13:55:24 -08:00
watchdog watchdog: core: dt: add support for the timeout-sec dt property 2013-03-01 12:48:36 +01:00
wimax
x86 Merge branch 'x86/microcode' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-22 19:22:52 -08:00
xtensa xtensa: initialize atomctl SR 2012-12-18 21:10:22 -08:00
zh_CN Driver core patches for 3.9-rc1 2013-02-21 12:05:51 -08:00
.gitignore
00-INDEX ImgTec Meta architecture changes for v3.9-rc1 2013-03-03 12:06:09 -08:00
applying-patches.txt
atomic_ops.txt Documentation: Memory barrier semantics of atomic_xchg() 2013-01-08 14:14:55 -08:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
Changes
circular-buffers.txt
clk.txt
coccinelle.txt coccicheck: Allow the user to give a V= (verbose) argument 2013-02-22 11:39:13 +01:00
CodingStyle Documentation: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:38:03 -08:00
cpu-hotplug.txt doc: Add x86 CPU0 online/offline feature 2012-11-14 09:39:44 -08:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt firmware: remove last vestiges of dabusb 2012-11-21 13:03:01 -08:00
digsig.txt
DMA-API-HOWTO.txt Documentation/DMA-API-HOWTO.txt: fix typo 2013-02-27 19:10:23 -08:00
DMA-API.txt dma-debug: New interfaces to debug dma mapping errors 2012-10-24 17:06:43 +02:00
DMA-attributes.txt common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute 2012-11-29 03:30:34 -08:00
dma-buf-sharing.txt dma-buf: implement vmap refcounting in the interface logic 2013-02-27 15:13:36 +05:30
DMA-ISA-LPC.txt
dmaengine.txt
dontdiff x86: remove offsets.h from .gitignore and dontdiff 2012-11-19 14:10:53 +01:00
dynamic-debug-howto.txt dynamic_debug: dynamic hex dump 2013-01-17 12:19:09 -08:00
edac.txt
eisa.txt
email-clients.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt gpiolib: provide provision to register pin ranges 2012-11-11 19:06:00 +01:00
highuid.txt
HOWTO HOWTO: fix double words typo 2012-12-10 15:54:27 +01:00
hw_random.txt
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt Documentation: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:38:03 -08:00
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi: add options to disable openfirmware and PCI scanning 2013-02-27 19:10:21 -08:00
IRQ-affinity.txt
IRQ-domain.txt irqdomain: update documentation 2012-12-05 23:52:10 +00:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt Kernel-doc: Convention: Use a "Return" section to describe return values 2012-11-27 21:08:57 +01:00
kernel-docs.txt
kernel-parameters.txt Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-04-20 18:40:36 -07:00
kmemcheck.txt
kmemleak.txt
kobject.txt Documentation: Fix "struct kobj_type" to include newer members. 2012-09-04 16:06:34 -07:00
kprobes.txt
kref.txt kref: Add kref_get_unless_zero documentation 2012-11-28 18:36:06 +10:00
ldm.txt
local_ops.txt
lockdep-design.txt
lockstat.txt locking/stat: Fix a typo 2013-02-19 08:42:37 +01:00
lockup-watchdogs.txt
logo.gif
logo.txt
magic-number.txt wanrouter: completely decouple obsolete code from kernel. 2013-01-31 19:20:33 -05:00
Makefile
ManagementStyle
md.txt
media-framework.txt [media] Documentation/media-framework.txt: fix a sentence 2013-02-08 13:27:13 -02:00
memory-barriers.txt Documentation: Memory barrier semantics of atomic_xchg() 2013-01-08 14:14:55 -08:00
memory-hotplug.txt hotplug: update nodemasks management 2012-12-12 17:38:33 -08:00
mono.txt
mutex-design.txt
nommu-mmap.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt percpu-rw-semaphore: fix documentation typos 2012-09-26 19:56:15 +02:00
pi-futex.txt
pinctrl.txt drivers/pinctrl: grab default handles from device core 2013-01-23 16:39:51 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt Randy has moved 2013-03-08 15:05:34 -08:00
pwm.txt pwm: add devm_pwm_get() and devm_pwm_put() 2012-09-10 17:05:45 +02:00
ramoops.txt pstore/ftrace: Convert to its own enable/disable debugfs knob 2012-09-06 22:16:58 -07:00
rbtree.txt rbtree: move augmented rbtree functionality to rbtree_augmented.h 2012-10-09 16:22:40 +09:00
remoteproc.txt remoteproc: add rproc_report_crash function to notify rproc crashes 2012-09-18 12:53:22 +03:00
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt Documentation: remove __dev* attributes. 2013-01-03 15:57:16 -08:00
rt-mutex-design.txt
rt-mutex.txt
rtc.txt rtc-proc: permit the /proc/driver/rtc device to use other devices 2012-10-06 03:05:01 +09:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
smsc_ece1099.txt mfd: smsc: Add support for smsc gpio io/keypad driver 2012-10-01 15:27:48 +02:00
sparse.txt Documentation/sparse.txt: document context annotations for lock checking 2012-12-17 17:15:23 -08:00
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt
static-keys.txt
SubmitChecklist
SubmittingDrivers
SubmittingPatches Randy has moved 2013-03-08 15:05:34 -08:00
svga.txt
sysfs-rules.txt
sysrq.txt sparc64: Add global PMU register dumping via sysrq. 2012-10-16 09:34:01 -07:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt vfio: Trivial Documentation correction 2012-09-21 10:48:03 -06:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt
xz.txt
zorro.txt