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-rw-r--r--include/linux/drbd_limits.h251
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diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
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+++ b/include/linux/drbd_limits.h
@@ -0,0 +1,251 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ drbd_limits.h
+ This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
+*/
+
+/*
+ * Our current limitations.
+ * Some of them are hard limits,
+ * some of them are arbitrary range limits, that make it easier to provide
+ * feedback about nonsense settings for certain configurable values.
+ */
+
+#ifndef DRBD_LIMITS_H
+#define DRBD_LIMITS_H 1
+
+#define DEBUG_RANGE_CHECK 0
+
+#define DRBD_MINOR_COUNT_MIN 1
+#define DRBD_MINOR_COUNT_MAX 255
+#define DRBD_MINOR_COUNT_DEF 32
+#define DRBD_MINOR_COUNT_SCALE '1'
+
+#define DRBD_VOLUME_MAX 65535
+
+#define DRBD_DIALOG_REFRESH_MIN 0
+#define DRBD_DIALOG_REFRESH_MAX 600
+#define DRBD_DIALOG_REFRESH_SCALE '1'
+
+/* valid port number */
+#define DRBD_PORT_MIN 1
+#define DRBD_PORT_MAX 0xffff
+#define DRBD_PORT_SCALE '1'
+
+/* startup { */
+ /* if you want more than 3.4 days, disable */
+#define DRBD_WFC_TIMEOUT_MIN 0
+#define DRBD_WFC_TIMEOUT_MAX 300000
+#define DRBD_WFC_TIMEOUT_DEF 0
+#define DRBD_WFC_TIMEOUT_SCALE '1'
+
+#define DRBD_DEGR_WFC_TIMEOUT_MIN 0
+#define DRBD_DEGR_WFC_TIMEOUT_MAX 300000
+#define DRBD_DEGR_WFC_TIMEOUT_DEF 0
+#define DRBD_DEGR_WFC_TIMEOUT_SCALE '1'
+
+#define DRBD_OUTDATED_WFC_TIMEOUT_MIN 0
+#define DRBD_OUTDATED_WFC_TIMEOUT_MAX 300000
+#define DRBD_OUTDATED_WFC_TIMEOUT_DEF 0
+#define DRBD_OUTDATED_WFC_TIMEOUT_SCALE '1'
+/* }*/
+
+/* net { */
+ /* timeout, unit centi seconds
+ * more than one minute timeout is not useful */
+#define DRBD_TIMEOUT_MIN 1
+#define DRBD_TIMEOUT_MAX 600
+#define DRBD_TIMEOUT_DEF 60 /* 6 seconds */
+#define DRBD_TIMEOUT_SCALE '1'
+
+ /* If backing disk takes longer than disk_timeout, mark the disk as failed */
+#define DRBD_DISK_TIMEOUT_MIN 0 /* 0 = disabled */
+#define DRBD_DISK_TIMEOUT_MAX 6000 /* 10 Minutes */
+#define DRBD_DISK_TIMEOUT_DEF 0 /* disabled */
+#define DRBD_DISK_TIMEOUT_SCALE '1'
+
+ /* active connection retries when C_WF_CONNECTION */
+#define DRBD_CONNECT_INT_MIN 1
+#define DRBD_CONNECT_INT_MAX 120
+#define DRBD_CONNECT_INT_DEF 10 /* seconds */
+#define DRBD_CONNECT_INT_SCALE '1'
+
+ /* keep-alive probes when idle */
+#define DRBD_PING_INT_MIN 1
+#define DRBD_PING_INT_MAX 120
+#define DRBD_PING_INT_DEF 10
+#define DRBD_PING_INT_SCALE '1'
+
+ /* timeout for the ping packets.*/
+#define DRBD_PING_TIMEO_MIN 1
+#define DRBD_PING_TIMEO_MAX 300
+#define DRBD_PING_TIMEO_DEF 5
+#define DRBD_PING_TIMEO_SCALE '1'
+
+ /* max number of write requests between write barriers */
+#define DRBD_MAX_EPOCH_SIZE_MIN 1
+#define DRBD_MAX_EPOCH_SIZE_MAX 20000
+#define DRBD_MAX_EPOCH_SIZE_DEF 2048
+#define DRBD_MAX_EPOCH_SIZE_SCALE '1'
+
+ /* I don't think that a tcp send buffer of more than 10M is useful */
+#define DRBD_SNDBUF_SIZE_MIN 0
+#define DRBD_SNDBUF_SIZE_MAX (10<<20)
+#define DRBD_SNDBUF_SIZE_DEF 0
+#define DRBD_SNDBUF_SIZE_SCALE '1'
+
+#define DRBD_RCVBUF_SIZE_MIN 0
+#define DRBD_RCVBUF_SIZE_MAX (10<<20)
+#define DRBD_RCVBUF_SIZE_DEF 0
+#define DRBD_RCVBUF_SIZE_SCALE '1'
+
+ /* @4k PageSize -> 128kB - 512MB */
+#define DRBD_MAX_BUFFERS_MIN 32
+#define DRBD_MAX_BUFFERS_MAX 131072
+#define DRBD_MAX_BUFFERS_DEF 2048
+#define DRBD_MAX_BUFFERS_SCALE '1'
+
+ /* @4k PageSize -> 4kB - 512MB */
+#define DRBD_UNPLUG_WATERMARK_MIN 1
+#define DRBD_UNPLUG_WATERMARK_MAX 131072
+#define DRBD_UNPLUG_WATERMARK_DEF (DRBD_MAX_BUFFERS_DEF/16)
+#define DRBD_UNPLUG_WATERMARK_SCALE '1'
+
+ /* 0 is disabled.
+ * 200 should be more than enough even for very short timeouts */
+#define DRBD_KO_COUNT_MIN 0
+#define DRBD_KO_COUNT_MAX 200
+#define DRBD_KO_COUNT_DEF 7
+#define DRBD_KO_COUNT_SCALE '1'
+/* } */
+
+/* syncer { */
+ /* FIXME allow rate to be zero? */
+#define DRBD_RESYNC_RATE_MIN 1
+/* channel bonding 10 GbE, or other hardware */
+#define DRBD_RESYNC_RATE_MAX (4 << 20)
+#define DRBD_RESYNC_RATE_DEF 250
+#define DRBD_RESYNC_RATE_SCALE 'k' /* kilobytes */
+
+#define DRBD_AL_EXTENTS_MIN 67
+ /* we use u16 as "slot number", (u16)~0 is "FREE".
+ * If you use >= 292 kB on-disk ring buffer,
+ * this is the maximum you can use: */
+#define DRBD_AL_EXTENTS_MAX 0xfffe
+#define DRBD_AL_EXTENTS_DEF 1237
+#define DRBD_AL_EXTENTS_SCALE '1'
+
+#define DRBD_MINOR_NUMBER_MIN -1
+#define DRBD_MINOR_NUMBER_MAX ((1 << 20) - 1)
+#define DRBD_MINOR_NUMBER_DEF -1
+#define DRBD_MINOR_NUMBER_SCALE '1'
+
+/* } */
+
+/* drbdsetup XY resize -d Z
+ * you are free to reduce the device size to nothing, if you want to.
+ * the upper limit with 64bit kernel, enough ram and flexible meta data
+ * is 1 PiB, currently. */
+/* DRBD_MAX_SECTORS */
+#define DRBD_DISK_SIZE_MIN 0
+#define DRBD_DISK_SIZE_MAX (1 * (2LLU << 40))
+#define DRBD_DISK_SIZE_DEF 0 /* = disabled = no user size... */
+#define DRBD_DISK_SIZE_SCALE 's' /* sectors */
+
+#define DRBD_ON_IO_ERROR_DEF EP_DETACH
+#define DRBD_FENCING_DEF FP_DONT_CARE
+#define DRBD_AFTER_SB_0P_DEF ASB_DISCONNECT
+#define DRBD_AFTER_SB_1P_DEF ASB_DISCONNECT
+#define DRBD_AFTER_SB_2P_DEF ASB_DISCONNECT
+#define DRBD_RR_CONFLICT_DEF ASB_DISCONNECT
+#define DRBD_ON_NO_DATA_DEF OND_IO_ERROR
+#define DRBD_ON_CONGESTION_DEF OC_BLOCK
+#define DRBD_READ_BALANCING_DEF RB_PREFER_LOCAL
+
+#define DRBD_MAX_BIO_BVECS_MIN 0
+#define DRBD_MAX_BIO_BVECS_MAX 128
+#define DRBD_MAX_BIO_BVECS_DEF 0
+#define DRBD_MAX_BIO_BVECS_SCALE '1'
+
+#define DRBD_C_PLAN_AHEAD_MIN 0
+#define DRBD_C_PLAN_AHEAD_MAX 300
+#define DRBD_C_PLAN_AHEAD_DEF 20
+#define DRBD_C_PLAN_AHEAD_SCALE '1'
+
+#define DRBD_C_DELAY_TARGET_MIN 1
+#define DRBD_C_DELAY_TARGET_MAX 100
+#define DRBD_C_DELAY_TARGET_DEF 10
+#define DRBD_C_DELAY_TARGET_SCALE '1'
+
+#define DRBD_C_FILL_TARGET_MIN 0
+#define DRBD_C_FILL_TARGET_MAX (1<<20) /* 500MByte in sec */
+#define DRBD_C_FILL_TARGET_DEF 100 /* Try to place 50KiB in socket send buffer during resync */
+#define DRBD_C_FILL_TARGET_SCALE 's' /* sectors */
+
+#define DRBD_C_MAX_RATE_MIN 250
+#define DRBD_C_MAX_RATE_MAX (4 << 20)
+#define DRBD_C_MAX_RATE_DEF 102400
+#define DRBD_C_MAX_RATE_SCALE 'k' /* kilobytes */
+
+#define DRBD_C_MIN_RATE_MIN 0
+#define DRBD_C_MIN_RATE_MAX (4 << 20)
+#define DRBD_C_MIN_RATE_DEF 250
+#define DRBD_C_MIN_RATE_SCALE 'k' /* kilobytes */
+
+#define DRBD_CONG_FILL_MIN 0
+#define DRBD_CONG_FILL_MAX (10<<21) /* 10GByte in sectors */
+#define DRBD_CONG_FILL_DEF 0
+#define DRBD_CONG_FILL_SCALE 's' /* sectors */
+
+#define DRBD_CONG_EXTENTS_MIN DRBD_AL_EXTENTS_MIN
+#define DRBD_CONG_EXTENTS_MAX DRBD_AL_EXTENTS_MAX
+#define DRBD_CONG_EXTENTS_DEF DRBD_AL_EXTENTS_DEF
+#define DRBD_CONG_EXTENTS_SCALE DRBD_AL_EXTENTS_SCALE
+
+#define DRBD_PROTOCOL_DEF DRBD_PROT_C
+
+#define DRBD_DISK_BARRIER_DEF 0
+#define DRBD_DISK_FLUSHES_DEF 1
+#define DRBD_DISK_DRAIN_DEF 1
+#define DRBD_MD_FLUSHES_DEF 1
+#define DRBD_TCP_CORK_DEF 1
+#define DRBD_AL_UPDATES_DEF 1
+
+/* We used to ignore the discard_zeroes_data setting.
+ * To not change established (and expected) behaviour,
+ * by default assume that, for discard_zeroes_data=0,
+ * we can make that an effective discard_zeroes_data=1,
+ * if we only explicitly zero-out unaligned partial chunks. */
+#define DRBD_DISCARD_ZEROES_IF_ALIGNED_DEF 1
+
+/* Some backends pretend to support WRITE SAME,
+ * but fail such requests when they are actually submitted.
+ * This is to tell DRBD to not even try. */
+#define DRBD_DISABLE_WRITE_SAME_DEF 0
+
+#define DRBD_ALLOW_TWO_PRIMARIES_DEF 0
+#define DRBD_ALWAYS_ASBP_DEF 0
+#define DRBD_USE_RLE_DEF 1
+#define DRBD_CSUMS_AFTER_CRASH_ONLY_DEF 0
+
+#define DRBD_AL_STRIPES_MIN 1
+#define DRBD_AL_STRIPES_MAX 1024
+#define DRBD_AL_STRIPES_DEF 1
+#define DRBD_AL_STRIPES_SCALE '1'
+
+#define DRBD_AL_STRIPE_SIZE_MIN 4
+#define DRBD_AL_STRIPE_SIZE_MAX 16777216
+#define DRBD_AL_STRIPE_SIZE_DEF 32
+#define DRBD_AL_STRIPE_SIZE_SCALE 'k' /* kilobytes */
+
+#define DRBD_SOCKET_CHECK_TIMEO_MIN 0
+#define DRBD_SOCKET_CHECK_TIMEO_MAX DRBD_PING_TIMEO_MAX
+#define DRBD_SOCKET_CHECK_TIMEO_DEF 0
+#define DRBD_SOCKET_CHECK_TIMEO_SCALE '1'
+
+#define DRBD_RS_DISCARD_GRANULARITY_MIN 0
+#define DRBD_RS_DISCARD_GRANULARITY_MAX (1<<20) /* 1MiByte */
+#define DRBD_RS_DISCARD_GRANULARITY_DEF 0 /* disabled by default */
+#define DRBD_RS_DISCARD_GRANULARITY_SCALE '1' /* bytes */
+
+#endif