Re: [PATCH] partitions/msdos.c
On Sat, 19 Mar 2005, Werner Almesberger wrote: Andries Brouwer wrote: The two variants are: (i) partition tells the kernel to do the partition table reading, and (ii) partition uses partx to read the partition table and tells the kernel one-by-one about the partitions found this way. I guess, once you've reached the point where the kernel is unable to find partitions without user-space help, you may as well do everything in user space. I agree. This is userspace job. This can be done very easily using device-mapper. I think EVMS does something similar. I even asked on LKML some time ago about option for disabling kernel partition driver (maybe for some devices) from kernel command line to allow other tools do the job (because now I have unusable /dev/sda1 and usable /dev/evms/sda1 and this leads to stupid mistakes). But there were no replies. Grzegorz Kulewski - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
Andries Brouwer wrote: > In other words, we need the user space command `partition', > where "partition -t dos /dev/sda" reads a DOS-type partition > table. So if you e.g. hotplug a new device, its partitions won't be accessible before you (or some hotplug manager, etc.) run "partition" ? > The two variants are: (i) partition tells the kernel > to do the partition table reading, and (ii) partition uses partx > to read the partition table and tells the kernel one-by-one > about the partitions found this way. I guess, once you've reached the point where the kernel is unable to find partitions without user-space help, you may as well do everything in user space. > Since this is a fundamental change, Pretty much, yes. Except for a few embedded systems (*), this would mark the end of kernels that can do anything useful without initrd or initramfs. (*) Oh, regarding the other exception, ceterum censeo nfsroot esse delendam. > a long transition period > is needed, and that period could start with a kernel boot parameter > telling the kernel not to do partition table parsing on a particular > disk, or a particular type of disks, or all disks. ... and allow "partition" to override partitions previously auto-detected by the kernel. That way, you can phase in "partition" without needing to change your kernel setup. Besides, the ability to correct past mistakes would also be useful if auto-detection from user space yields garbage. - Werner -- _ / Werner Almesberger, Buenos Aires, Argentina [EMAIL PROTECTED] / /_http://www.almesberger.net// - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sun, Feb 27, 2005 at 12:40:53AM +0100, Andries Brouwer wrote: > (Concerning the "size" version: it occurred to me that there is one > very minor objection: For extended partitions so far the size did > not normally play a role. Only the starting sector was significant. > If, at some moment we decide also to check the size, then a weaker > check, namely only checking for non-extended partitions, might be > better at first.) I recently encountered a disk that had clipping enabled. If you go for the size implementation be careful that people can still run a program to unclip the disk after the disk has been detected and the partition rejected Roger. -- ** [EMAIL PROTECTED] ** http://www.BitWizard.nl/ ** +31-15-2600998 ** *-- BitWizard writes Linux device drivers for any device you may have! --* Q: It doesn't work. A: Look buddy, doesn't work is an ambiguous statement. Does it sit on the couch all day? Is it unemployed? Please be specific! Define 'it' and what it isn't doing. - Adapted from lxrbot FAQ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
> "Linus" == Linus Torvalds <[EMAIL PROTECTED]> writes: Linus> On Sun, 27 Feb 2005, Uwe Bonnes wrote: >> on a Suse 9.2 System with Suse Hotplug, the phantom partition was >> somehow recognized as Reiserfs, and then the Hotplug mechanism trying >> to mount the bogus partition as a Reiser Filesystem ended in an >> Oops... Linus> Heh. That oops would be interesting in itself, since it implies Linus> that reiserfs is not doing very well on the sanity-checking Linus> front. Linus> But yes, point taken. I have to admit, I saw the oops only with a glimpse of the eye, trying to do other tasks at that moment about a week ago. The oops also left no trace in the syslog. As syslog is on a reiserfs partition, perhaps reiserfs refused no write anything after the oops. Trying to reproduce by mounting the bogus sda4 partition of the usb stick on two different setups, now reiserfs clearly refuses to mount it. Perhaps the oops was unrelated. Find appended an oops happening yesterday, related to reiserfs too. Probably totally useless, as run on a custom Suse kernel. A reiserfsck after the oops corrected some errors, perhaps introduced by the oops one week earlier. I don't understand what to do about the missing ksyms.. B.t.w.: While I have you attention, can I point you to http://www.ussg.iu.edu/hypermail/linux/kernel/0410.1/1246.html where I reported a Linux missbehaviour and a possible patch. I tried to get the attention of several kernel developpers, to no avail so long ... Cheers -- Uwe Bonnes[EMAIL PROTECTED] Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt - Tel. 06151 162516 Fax. 06151 164321 -- ==undecoded excerpt from the syslog=== Feb 26 18:47:40 r50 kernel: Unable to handle kernel paging request at virtual address 8a5e65b8 Feb 26 18:47:40 r50 kernel: printing eip: Feb 26 18:47:40 r50 kernel: c01d1482 Feb 26 18:47:40 r50 kernel: *pde = Feb 26 18:47:40 r50 kernel: Oops: [#1] Feb 26 18:47:40 r50 kernel: Modules linked in: usb_storage nvram usbserial parport_pc lp parport cpufreq_userspace speedstep_centrino freq_table thermal processor fan button battery ac edd snd_pcm_oss snd_mixer_oss snd_intel8x0 snd_ac97_codec snd_pcm snd_timer snd soundcore snd_page_alloc ipv6 pcmcia joydev sg st sd_mod sr_mod scsi_mod ide_cd cdrom subfs nls_utf8 ntfs i2c_i801 i2c_core cinergyT2 dvb_core e1000 ehci_hcd hw_random uhci_hcd ohci1394 ieee1394 yenta_socket rsrc_nonstatic pcmcia_core intel_agp agpgart evdev dm_mod usbcore reiserfs Feb 26 18:47:40 r50 kernel: CPU:0 Feb 26 18:47:40 r50 kernel: EIP:0060:[]Tainted: G U VLI Feb 26 18:47:40 r50 kernel: EFLAGS: 00010202 (2.6.11-rc4-bk2) Feb 26 18:47:40 r50 kernel: EIP is at memcpy+0x12/0x30 Feb 26 18:47:40 r50 kernel: eax: 0004 ebx: df47b058 ecx: 0004 edx: 0010 Feb 26 18:47:40 r50 kernel: esi: 8a5e65b8 edi: df47b058 ebp: c35d7b34 esp: c35d7af4 Feb 26 18:47:40 r50 kernel: ds: 007b es: 007b ss: 0068 Feb 26 18:47:40 r50 kernel: Process xauth (pid: 30301, threadinfo=c35d6000 task=c73d5aa0) Feb 26 18:47:40 r50 kernel: Stack: dfb3c000 df451458 c35d7c94 e0a5acf4 7a5a c35d7c94 df6a9ad8 e0a70707 Feb 26 18:47:40 r50 kernel:df6a9ad8 7a5a 0004 df451458 c35d7c94 df6a9ad8 df451458 0005 Feb 26 18:47:41 r50 kernel:c35d7c94 c15cf424 df451458 0004 c35d7ea8 0027 0001 c35d7c94 Feb 26 18:47:41 r50 kernel: Call Trace: Feb 26 18:47:41 r50 kernel: [] replace_key+0x34/0x70 [reiserfs] Feb 26 18:47:41 r50 kernel: [] internal_shift_left+0xa7/0xd0 [reiserfs] Feb 26 18:47:41 r50 kernel: [] balance_internal_when_delete+0x1ca/0x220 [reiserfs] Feb 26 18:47:41 r50 kernel: [] balance_internal+0x5bd/0x800 [reiserfs] Feb 26 18:47:41 r50 kernel: [] io_schedule+0xe/0x20 Feb 26 18:47:41 r50 kernel: [] bh_lru_install+0x89/0xb0 Feb 26 18:47:41 r50 kernel: [] mark_page_accessed+0x28/0x30 Feb 26 18:47:41 r50 kernel: [] dc_check_balance_internal+0x37b/0x390 [reiserfs] Feb 26 18:47:41 r50 kernel: [] do_balance+0xc7/0xf0 [reiserfs] Feb 26 18:47:41 r50 kernel: [] fix_nodes+0x31c/0x360 [reiserfs] Feb 26 18:47:41 r50 kernel: [] reiserfs_cut_from_item+0x32e/0x4e0 [reiserfs] Feb 26 18:47:41 r50 kernel: [] reiserfs_do_truncate+0x2e3/0x540 [reiserfs] Feb 26 18:47:41 r50 kernel: [] reiserfs_delete_object+0x28/0x60 [reiserfs] Feb 26 18:47:41 r50 kernel: [] reiserfs_delete_inode+0x68/0xe0 [reiserfs] Feb 26 18:47:41 r50 kernel: [] truncate_inode_pages+0x9/0x10 Feb 26 18:47:41 r50 kernel: [] reiserfs_delete_inode+0x0/0xe0 [reiserfs] Feb 26 18:47:41 r50 kernel: [] generic_delete_inode+0xa4/0x130 Feb 26 18:47:41 r50 kernel: [] iput+0x4d/0x70 Feb 26 18:47:41 r50 kernel: [] sys_unlink+0xba/0x130 Feb 26 18:47:41 r50 kernel: [] do_munmap+0xcd/0x100 Feb 26 18:47:41 r50 kernel: [] sysenter_past_esp+0x52/0x79 Feb 26 18:47:41 r50 kernel: Code: e0 ff ff 21 e2 3b 42 18 73 06 8b 50 fd 31 c0 c3 31 d2 b8
Re: [PATCH] partitions/msdos.c
On Sun, Feb 27, 2005 at 01:47:43AM +0100, Uwe Bonnes wrote: > on a Suse 9.2 System with Suse Hotplug, the phantom partition was somehow > recognized as Reiserfs, and then the Hotplug mechanism trying to mount the > bogus partition as a Reiser Filesystem ended in an Oops... Always report the oops. It is well-known that mounting garbage may crash the kernel. Earlier the reply was "don't do that then". Nowadays we have more layers of software trying to probe and do automatic things, and the kernel must survive attempts to mount garbage. Andries - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sun, 27 Feb 2005, Uwe Bonnes wrote: > > on a Suse 9.2 System with Suse Hotplug, the phantom partition was somehow > recognized as Reiserfs, and then the Hotplug mechanism trying to mount the > bogus partition as a Reiser Filesystem ended in an Oops... Heh. That oops would be interesting in itself, since it implies that reiserfs is not doing very well on the sanity-checking front. But yes, point taken. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
> "Linus" == Linus Torvalds <[EMAIL PROTECTED]> writes: Linus> On Sun, 27 Feb 2005, Andries Brouwer wrote: >> (Concerning the "size" version: it occurred to me that there is one >> very minor objection: For extended partitions so far the size did not >> normally play a role. Only the starting sector was significant. If, >> at some moment we decide also to check the size, then a weaker check, >> namely only checking for non-extended partitions, might be better at >> first.) Linus> Yes. I agree - checking the size is likely _more_ dangerous and Linus> likely to break something silly than checking the ID for zero. Linus> So your patch it is. I'll put it in immediately after doing a Linus> 2.6.11 (no need to worry about getting into 2.6.11, since afaik Linus> the worst problem right now is an extra partition that isn't Linus> usable). Well, on a Suse 9.2 System with Suse Hotplug, the phantom partition was somehow recognized as Reiserfs, and then the Hotplug mechanism trying to mount the bogus partition as a Reiser Filesystem ended in an Oops... -- Uwe Bonnes[EMAIL PROTECTED] Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt - Tel. 06151 162516 Fax. 06151 164321 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sat, Feb 26, 2005 at 03:46:03PM -0800, Linus Torvalds wrote:
> We should probably do the same for the
> extended partition case, just to be consistent.
True.
diff -uprN -X /linux/dontdiff a/fs/partitions/msdos.c b/fs/partitions/msdos.c
--- a/fs/partitions/msdos.c 2004-12-29 03:39:55.0 +0100
+++ b/fs/partitions/msdos.c 2005-02-27 01:10:06.0 +0100
@@ -114,6 +114,9 @@ parse_extended(struct parsed_partitions
*/
for (i=0; i<4; i++, p++) {
u32 offs, size, next;
+
+ if (SYS_IND(p) == 0)
+ continue;
if (!NR_SECTS(p) || is_extended_partition(p))
continue;
@@ -430,6 +433,8 @@ int msdos_partition(struct parsed_partit
for (slot = 1 ; slot <= 4 ; slot++, p++) {
u32 start = START_SECT(p)*sector_size;
u32 size = NR_SECTS(p)*sector_size;
+ if (SYS_IND(p) == 0)
+ continue;
if (!size)
continue;
if (is_extended_partition(p)) {
-
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Re: [PATCH] partitions/msdos.c
On Sun, 27 Feb 2005, Andries Brouwer wrote: > > (Concerning the "size" version: it occurred to me that there is one > very minor objection: For extended partitions so far the size did > not normally play a role. Only the starting sector was significant. > If, at some moment we decide also to check the size, then a weaker > check, namely only checking for non-extended partitions, might be > better at first.) Yes. I agree - checking the size is likely _more_ dangerous and likely to break something silly than checking the ID for zero. So your patch it is. I'll put it in immediately after doing a 2.6.11 (no need to worry about getting into 2.6.11, since afaik the worst problem right now is an extra partition that isn't usable). Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sun, 27 Feb 2005, Uwe Bonnes wrote: > > /dev/sda4 3512348 6003585 698791990+ 0 Empty > Partition 4 has different physical/logical beginnings (non-Linux?): > phys=(0, 0, 0) logical=(3512347, 6, 16) > Partition 4 has different physical/logical endings: > phys=(0, 0, 0) logical=(6003584, 7, 6) > Partition 4 does not end on cylinder boundary. Yeah, your case could check for zero in the physical sector stuff too, but I'm not sure that matters, since nobody really cares about the physical values and they've long been too limited to matter. So I'm not at all convinced that adding a few more checks for zero would be any better than checking the one zero that Andries does. I think Andries' patch is fine. We should probably do the same for the extended partition case, just to be consistent. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sat, Feb 26, 2005 at 03:12:28PM -0800, Linus Torvalds wrote: > > The default fdisk will assign type 83 to a newly created partition. > > Ok. Is that a "it has done so for the last 5 years" thing? The last twelve years. > > (About type 0: DOS has used type 0 as definition of unused. It is not > > bad if Linux uses DOS-conventions for a DOS-type partition table.) > > Agreed. At the same time, I could well imagine that some people might use > such a type exactly to make DOS ignore it (but I assume the same is true > of the regular 0x83 type too, so maybe I'm just being difficult). > > There's certainly a good argument for fixing a known problem (Uwe) and a > small enough risk of it breaking anything else. Yes. Andries (Concerning the "size" version: it occurred to me that there is one very minor objection: For extended partitions so far the size did not normally play a role. Only the starting sector was significant. If, at some moment we decide also to check the size, then a weaker check, namely only checking for non-extended partitions, might be better at first.) (Yes, disk capacity is not always known - see e.g. ll_rw_blk.c: /* Test device or partition size, when known. */ See also sd.c, with the strange sdkp->capacity = 0x20; /* 1 GB - random */ In such cases we just access the blocks user space tells us to access.) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
> "Linus" == Linus Torvalds <[EMAIL PROTECTED]> writes: Linus> On Sat, 26 Feb 2005, Linus Torvalds wrote: >> Would it not make more sense to just sanity-check the size itself, >> and throw it out if the partition size (plus start) is bigger than >> the disk size? Linus> Something like this (TOTALLY UNTESTED AS USUAL!)? Yes, no phantom partitions also with your approach. Linus> What does fdisk and other tools do on that disk? Just out of Linus> interest.. To be honest: r50:~ # fdisk /dev/sda Command (m for help): p Disk /dev/sda: 65 MB, 65536000 bytes 17 heads, 33 sectors/track, 228 cylinders Units = cylinders of 561 * 512 = 287232 bytes Device Boot Start End Blocks Id System /dev/sda1 1 229 63981+ 6 FAT16 Partition 1 has different physical/logical beginnings (non-Linux?): phys=(0, 1, 1) logical=(0, 1, 5) Partition 1 has different physical/logical endings: phys=(125, 16, 33) logical=(228, 2, 26) /dev/sda4 3512348 6003585 698791990+ 0 Empty Partition 4 has different physical/logical beginnings (non-Linux?): phys=(0, 0, 0) logical=(3512347, 6, 16) Partition 4 has different physical/logical endings: phys=(0, 0, 0) logical=(6003584, 7, 6) Partition 4 does not end on cylinder boundary. -- Uwe Bonnes[EMAIL PROTECTED] Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt - Tel. 06151 162516 Fax. 06151 164321 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sat, 26 Feb 2005, Andries Brouwer wrote: > > The default fdisk will assign type 83 to a newly created partition. Ok. Is that a "it has done so for the last 5 years" thing? > (About type 0: DOS has used type 0 as definition of unused. It is not > bad if Linux uses DOS-conventions for a DOS-type partition table.) Agreed. At the same time, I could well imagine that some people might use such a type exactly to make DOS ignore it (but I assume the same is true of the regular 0x83 type too, so maybe I'm just being difficult). There's certainly a good argument for fixing a known problem (Uwe) and a small enough risk of it breaking anything else. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sat, Feb 26, 2005 at 02:28:45PM -0800, Linus Torvalds wrote: > Would it not make more sense to just sanity-check the size itself, and > throw it out if the partition size (plus start) is bigger than the disk > size? I don't mind. > There might well be people use use partition type 0, just because they > just never _set_ the partition type.. I don't think Linux has ever cared > about any type except for the "extended partition" type, so checking for > zero doesn't seem very safe.. The default fdisk will assign type 83 to a newly created partition. One has to change it by hand to 0. So, I do not think testing against 0 is so bad. A heuristic, You give another heuristic. Probably there will be a point in time where we need both. (About type 0: DOS has used type 0 as definition of unused. It is not bad if Linux uses DOS-conventions for a DOS-type partition table.) Andries - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
On Sat, 26 Feb 2005, Linus Torvalds wrote:
>
> Would it not make more sense to just sanity-check the size itself, and
> throw it out if the partition size (plus start) is bigger than the disk
> size?
Something like this (TOTALLY UNTESTED AS USUAL!)?
What does fdisk and other tools do on that disk? Just out of interest..
Linus
---
= fs/partitions/msdos.c 1.26 vs edited =
--- 1.26/fs/partitions/msdos.c 2004-11-09 12:43:17 -08:00
+++ edited/fs/partitions/msdos.c2005-02-26 14:33:33 -08:00
@@ -381,6 +381,7 @@
int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
{
int sector_size = bdev_hardsect_size(bdev) / 512;
+ sector_t nr_sectors;
Sector sect;
unsigned char *data;
struct partition *p;
@@ -426,11 +427,12 @@
* On the second pass look inside *BSD, Unixware and Solaris partitions.
*/
+ nr_sectors = get_capacity(bdev->bd_disk);
state->next = 5;
for (slot = 1 ; slot <= 4 ; slot++, p++) {
u32 start = START_SECT(p)*sector_size;
u32 size = NR_SECTS(p)*sector_size;
- if (!size)
+ if (!size || size > nr_sectors)
continue;
if (is_extended_partition(p)) {
/* prevent someone doing mkfs or mkswap on an
-
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Re: [PATCH] partitions/msdos.c
On Sat, 26 Feb 2005, Uwe Bonnes wrote: > > Andrew, > > Andries> I think nobody uses such partitions seriously, but nevertheless > Andries> this should probably live in -mm for a while to see if anybody > Andries> complains. > > the partition table of the USB stick in question is valid: > > 1B0: 00 00 00 00 00 00 00 00 53 3F 3C B9 00 00 00 01 S?<. > 1C0: 01 00 06 10 21 7D 25 00 00 00 DB F3 01 00 00 00 !}%. > 1D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >* > 1F0: 00 00 00 00 00 00 00 54 72 75 6D 70 4D 53 55 AA ...TrumpMSU. > > Entry 1 is a FAT partition of exactly the size of the stick, and entries 2 > to 4 are empty, marked by id zero. However the manufacturer decided to put a > name string "Trump" ( /sbin/lsusb gives > Bus 004 Device 012: ID 090a:1bc0 Trumpion Microelectronics, Inc.) just before > the "55 AA" partition table magic and our code reads this string as a > (bogus) size for the fourth entry, taking it for real. Would it not make more sense to just sanity-check the size itself, and throw it out if the partition size (plus start) is bigger than the disk size? We already do that within extended partitions, ie we do if (offs + size > this_size) continue; to just ignore crap. For some reason we don't do this for the primary one (possibly because we don't trust disk size reporting, I guess). There might well be people use use partition type 0, just because they just never _set_ the partition type.. I don't think Linux has ever cared about any type except for the "extended partition" type, so checking for zero doesn't seem very safe.. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] partitions/msdos.c
> "Andries" == Andries Brouwer <[EMAIL PROTECTED]> writes: Andrew, Andries> I think nobody uses such partitions seriously, but nevertheless Andries> this should probably live in -mm for a while to see if anybody Andries> complains. the partition table of the USB stick in question is valid: 1B0: 00 00 00 00 00 00 00 00 53 3F 3C B9 00 00 00 01 S?<. 1C0: 01 00 06 10 21 7D 25 00 00 00 DB F3 01 00 00 00 !}%. 1D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 * 1F0: 00 00 00 00 00 00 00 54 72 75 6D 70 4D 53 55 AA ...TrumpMSU. Entry 1 is a FAT partition of exactly the size of the stick, and entries 2 to 4 are empty, marked by id zero. However the manufacturer decided to put a name string "Trump" ( /sbin/lsusb gives Bus 004 Device 012: ID 090a:1bc0 Trumpion Microelectronics, Inc.) just before the "55 AA" partition table magic and our code reads this string as a (bogus) size for the fourth entry, taking it for real. Please consider the patch for the main kernel distribution. Cheers -- Uwe Bonnes[EMAIL PROTECTED] Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt - Tel. 06151 162516 Fax. 06151 164321 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] partitions/msdos.c
A well-known kernel bug is that it guesses at the partition type
and the partitions on any disk it encounters. This is bad because
needless I/O is done, slowing down the boot, sometimes quite a lot,
especially when I/O errors occur. And it is bad because sometimes
we guess wrong.
In other words, we need the user space command `partition',
where "partition -t dos /dev/sda" reads a DOS-type partition
table. (And "partition /dev/sda" tries all known heuristics
to decide what type of partitioning might be present.)
The two variants are: (i) partition tells the kernel
to do the partition table reading, and (ii) partition uses partx
to read the partition table and tells the kernel one-by-one
about the partitions found this way.
Since this is a fundamental change, a long transition period
is needed, and that period could start with a kernel boot parameter
telling the kernel not to do partition table parsing on a particular
disk, or a particular type of disks, or all disks.
This could have been the intro to a patch doing that, but is not.
(It is just an RFC.)
The tiny patch below prompted the above - it was suggested by Uwe Bonnes
who encountered USB devices without partition table where our present
heuristics did not suffice to stop partition table parsing.
It causes the kernel to ignore partitions of type 0. A band-aid.
I think nobody uses such partitions seriously, but nevertheless this
should probably live in -mm for a while to see if anybody complains.
Andries
diff -uprN -X /linux/dontdiff a/fs/partitions/msdos.c b/fs/partitions/msdos.c
--- a/fs/partitions/msdos.c 2004-12-29 03:39:55.0 +0100
+++ b/fs/partitions/msdos.c 2005-02-26 22:21:06.0 +0100
@@ -430,6 +430,8 @@ int msdos_partition(struct parsed_partit
for (slot = 1 ; slot <= 4 ; slot++, p++) {
u32 start = START_SECT(p)*sector_size;
u32 size = NR_SECTS(p)*sector_size;
+ if (SYS_IND(p) == 0)
+ continue;
if (!size)
continue;
if (is_extended_partition(p)) {
-
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