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openSUSE:Evergreen:11.1:kernel-2.6.32
mdadm
super1-do-metadata-IO-in-sector_size-units.patch
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File super1-do-metadata-IO-in-sector_size-units.patch of Package mdadm
From ae8b146d524dd162f159f27938ed14df037e3ff8 Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@suse.de> Date: Tue, 3 Mar 2009 15:44:26 +1100 Subject: [PATCH 2/2] super1 - do metadata IO in sector_size units. If the sector size is > 512, we need to be more careful about alignment. The largest known sector size is 4096 and (fortunately) both the superblock and (in many cases) the bitmap are 4096-byte aligned. So there should be no data-overlap problems. The exception is when the bitmap is squeezed into the 3K after the superblock. This arrangement cannot currently be supported on 4K sector-size devices. Signed-off-by: NeilBrown <neilb@suse.de> --- super1.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 files changed, 64 insertions(+), 7 deletions(-) Index: mdadm-3.0-devel2/super1.c =================================================================== --- mdadm-3.0-devel2.orig/super1.c +++ mdadm-3.0-devel2/super1.c @@ -141,6 +141,64 @@ static unsigned int calc_sb_1_csum(struc return __cpu_to_le32(csum); } +static char abuf[4096+4096]; +static int aread(int fd, void *buf, int len) +{ + /* aligned read. + * On devices with a 4K sector size, we need to read + * the full sector and copy relevant bits into + * the buffer + */ + int bsize; + char *b; + int n; + if (ioctl(fd, BLKSSZGET, &bsize) != 0 || + bsize <= len) + return read(fd, buf, len); + if (bsize > 4096) + return -1; + b = (char*)(((long)(abuf+4096))&~4095UL); + + n = read(fd, b, bsize); + if (n <= 0) + return n; + lseek(fd, len - n, 1); + if (n > len) + n = len; + memcpy(buf, b, n); + return n; +} + +static int awrite(int fd, void *buf, int len) +{ + /* aligned write. + * On devices with a 4K sector size, we need to write + * the full sector. We pre-read if the sector is larger + * than the write. + * The address must be sector-aligned. + */ + int bsize; + char *b; + int n; + if (ioctl(fd, BLKSSZGET, &bsize) != 0 || + bsize <= len) + return write(fd, buf, len); + if (bsize > 4096) + return -1; + b = (char*)(((long)(abuf+4096))&~4095UL); + + n = read(fd, b, bsize); + if (n <= 0) + return n; + lseek(fd, -n, 1); + memcpy(b, buf, len); + n = write(fd, b, bsize); + if (n <= 0) + return n; + lseek(fd, len - n, 1); + return len; +} + #ifndef MDASSEMBLE static void examine_super1(struct supertype *st, char *homehost) { @@ -881,7 +939,7 @@ static int store_super1(struct supertype sbsize = sizeof(*sb) + 2 * __le32_to_cpu(sb->max_dev); sbsize = (sbsize+511)&(~511UL); - if (write(fd, sb, sbsize) != sbsize) + if (awrite(fd, sb, sbsize) != sbsize) return 4; if (sb->feature_map & __cpu_to_le32(MD_FEATURE_BITMAP_OFFSET)) { @@ -889,8 +947,8 @@ static int store_super1(struct supertype (((char*)sb)+1024); if (__le32_to_cpu(bm->magic) == BITMAP_MAGIC) { locate_bitmap1(st, fd); - if (write(fd, bm, ROUND_UP(sizeof(*bm),512)) != - ROUND_UP(sizeof(*bm),512)) + if (awrite(fd, bm, sizeof(*bm)) != + sizeof(*bm)) return 5; } } @@ -1187,7 +1245,7 @@ static int load_super1(struct supertype return 1; } - if (read(fd, super, 1024) != 1024) { + if (aread(fd, super, 1024) != 1024) { if (devname) fprintf(stderr, Name ": Cannot read superblock on %s\n", devname); @@ -1232,7 +1290,7 @@ static int load_super1(struct supertype * should get that written out. */ locate_bitmap1(st, fd); - if (read(fd, ((char*)super)+1024, 512) + if (aread(fd, ((char*)super)+1024, 512) != 512) goto no_bitmap; @@ -1470,8 +1528,7 @@ static int write_bitmap1(struct supertyp int rv = 0; int towrite, n; - char abuf[4096+512]; - char *buf = (char*)(((long)(abuf+512))&~511UL); + char *buf = (char*)(((long)(abuf+4096))&~4095UL); locate_bitmap1(st, fd);
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