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Date: Mon, 17 May 2010 16:44:55 -0500
From: Eric Sandeen <sandeen@...hat.com>
To: ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH V2] mke2fs: account for physical as well as logical sector
size
Eric Sandeen wrote:
> Some devices, notably 4k sector drives, may have a 512 logical
> sector size, mapped onto a 4k physical sector size.
>
> When mke2fs is ratcheting down the blocksize for small filesystems,
> or when a blocksize is specified on the commandline, we should not
> willingly go below the physical sector size of the device.
>
> When a blocksize is specified, we -must- not go below
> the logical sector size of the device.
>
> Add a new library function, ext2fs_get_device_phys_sectsize()
> to get the physical sector size if possible, and adjust the
> logic in mke2fs to enforce the above rules.
>
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
ping on this one?
-Eric
> ---
>
> (V2: just forgot to update the subject after changing the patch)
>
> diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> index 213a819..9c06048 100644
> --- a/lib/ext2fs/ext2fs.h
> +++ b/lib/ext2fs/ext2fs.h
> @@ -1086,6 +1086,7 @@ extern errcode_t ext2fs_get_device_size2(const char *file, int blocksize,
>
> /* getsectsize.c */
> errcode_t ext2fs_get_device_sectsize(const char *file, int *sectsize);
> +errcode_t ext2fs_get_device_phys_sectsize(const char *file, int *sectsize);
>
> /* i_block.c */
> errcode_t ext2fs_iblk_add_blocks(ext2_filsys fs, struct ext2_inode *inode,
> diff --git a/lib/ext2fs/getsectsize.c b/lib/ext2fs/getsectsize.c
> index ae9139d..0c7fa82 100644
> --- a/lib/ext2fs/getsectsize.c
> +++ b/lib/ext2fs/getsectsize.c
> @@ -26,15 +26,20 @@
> #include <linux/fd.h>
> #endif
>
> -#if defined(__linux__) && defined(_IO) && !defined(BLKSSZGET)
> +#if defined(__linux__) && defined(_IO)
> +#if !defined(BLKSSZGET)
> #define BLKSSZGET _IO(0x12,104)/* get block device sector size */
> #endif
> +#if !defined(BLKPBSZGET)
> +#define BLKPBSZGET _IO(0x12,123)/* get block physical sector size */
> +#endif
> +#endif
>
> #include "ext2_fs.h"
> #include "ext2fs.h"
>
> /*
> - * Returns the number of blocks in a partition
> + * Returns the logical sector size of a device
> */
> errcode_t ext2fs_get_device_sectsize(const char *file, int *sectsize)
> {
> @@ -58,3 +63,29 @@ errcode_t ext2fs_get_device_sectsize(const char *file, int *sectsize)
> close(fd);
> return 0;
> }
> +
> +/*
> + * Returns the physical sector size of a device
> + */
> +errcode_t ext2fs_get_device_phys_sectsize(const char *file, int *sectsize)
> +{
> + int fd;
> +
> +#ifdef HAVE_OPEN64
> + fd = open64(file, O_RDONLY);
> +#else
> + fd = open(file, O_RDONLY);
> +#endif
> + if (fd < 0)
> + return errno;
> +
> +#ifdef BLKPBSZGET
> + if (ioctl(fd, BLKPBSZGET, sectsize) >= 0) {
> + close(fd);
> + return 0;
> + }
> +#endif
> + *sectsize = 0;
> + close(fd);
> + return 0;
> +}
> diff --git a/lib/ext2fs/tst_getsectsize.c b/lib/ext2fs/tst_getsectsize.c
> index cb1b8c6..31599d2 100644
> --- a/lib/ext2fs/tst_getsectsize.c
> +++ b/lib/ext2fs/tst_getsectsize.c
> @@ -27,7 +27,7 @@
>
> int main(int argc, char **argv)
> {
> - int sectsize;
> + int lsectsize, psectsize;
> int retval;
>
> if (argc < 2) {
> @@ -35,13 +35,19 @@ int main(int argc, char **argv)
> exit(1);
> }
>
> - retval = ext2fs_get_device_sectsize(argv[1], §size);
> + retval = ext2fs_get_device_sectsize(argv[1], &lsectsize);
> if (retval) {
> com_err(argv[0], retval,
> "while calling ext2fs_get_device_sectsize");
> exit(1);
> }
> - printf("Device %s has a hardware sector size of %d.\n",
> - argv[1], sectsize);
> + retval = ext2fs_get_device_phys_sectsize(argv[1], &psectsize);
> + if (retval) {
> + com_err(argv[0], retval,
> + "while calling ext2fs_get_device_phys_sectsize");
> + exit(1);
> + }
> + printf("Device %s has logical/physical sector size of %d/%d.\n",
> + argv[1], lsectsize, psectsize);
> exit(0);
> }
> diff --git a/misc/mke2fs.c b/misc/mke2fs.c
> index 94b4c81..1a1307b 100644
> --- a/misc/mke2fs.c
> +++ b/misc/mke2fs.c
> @@ -1068,7 +1068,7 @@ static void PRS(int argc, char *argv[])
> int inode_size = 0;
> unsigned long flex_bg_size = 0;
> double reserved_ratio = 5.0;
> - int sector_size = 0;
> + int lsector_size = 0, psector_size = 0;
> int show_version_only = 0;
> unsigned long long num_inodes = 0; /* unsigned long long to catch too-large input */
> errcode_t retval;
> @@ -1586,16 +1586,25 @@ got_size:
> ((tmp = getenv("MKE2FS_FIRST_META_BG"))))
> fs_param.s_first_meta_bg = atoi(tmp);
>
> - /* Get the hardware sector size, if available */
> - retval = ext2fs_get_device_sectsize(device_name, §or_size);
> + /* Get the hardware sector sizes, if available */
> + retval = ext2fs_get_device_sectsize(device_name, &lsector_size);
> if (retval) {
> com_err(program_name, retval,
> _("while trying to determine hardware sector size"));
> exit(1);
> }
> + retval = ext2fs_get_device_phys_sectsize(device_name, &psector_size);
> + if (retval) {
> + com_err(program_name, retval,
> + _("while trying to determine physical sector size"));
> + exit(1);
> + }
> + /* Older kernels may not have physical/logical distinction */
> + if (!psector_size)
> + psector_size = lsector_size;
>
> if ((tmp = getenv("MKE2FS_DEVICE_SECTSIZE")) != NULL)
> - sector_size = atoi(tmp);
> + psector_size = atoi(tmp);
>
> if (blocksize <= 0) {
> use_bsize = get_int_from_profile(fs_types, "blocksize", 4096);
> @@ -1606,14 +1615,25 @@ got_size:
> (use_bsize > 4096))
> use_bsize = 4096;
> }
> - if (sector_size && use_bsize < sector_size)
> - use_bsize = sector_size;
> + if (psector_size && use_bsize < psector_size)
> + use_bsize = psector_size;
> if ((blocksize < 0) && (use_bsize < (-blocksize)))
> use_bsize = -blocksize;
> blocksize = use_bsize;
> ext2fs_blocks_count_set(&fs_param,
> ext2fs_blocks_count(&fs_param) /
> (blocksize / 1024));
> + } else {
> + if (blocksize < lsector_size || /* Impossible */
> + (!force && (blocksize < psector_size))) { /* Suboptimal */
> + com_err(program_name, EINVAL,
> + _("while setting blocksize; too small for device\n"));
> + exit(1);
> + } else if (blocksize < psector_size) {
> + fprintf(stderr, _("Warning: specified blocksize %d is "
> + "less than device physical sectorsize %d, "
> + "forced to continue\n"), blocksize, psector_size);
> + }
> }
>
> if (inode_ratio == 0) {
>
> --
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