* [PATCH] fix CONFIG_DEVFS=y root=<number>
@ 2003-01-04 8:01 Milton Miller
2003-01-04 8:36 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Milton Miller @ 2003-01-04 8:01 UTC (permalink / raw)
To: linux-kernel; +Cc: Helge Hafting, Andrew Morton
Based on a patch by Adam J. Richter <adam@yggdrasil.com> [1], this fixes
the problem since 2.5.47 with mounting a devfs=y system with root=<number>
sys_get_dents64 returns -EINVAL if there is not space for an entry, so
we need to activate the loop code to expand the buffer.
[1] http://marc.theaimsgroup.com/?l=linux-kernel&m=103762980207529&w=2
Tested with 2.5.53-um2
diff -Nru a/init/do_mounts.c b/init/do_mounts.c
--- a/init/do_mounts.c Sat Jan 4 00:14:34 2003
+++ b/init/do_mounts.c Sat Jan 4 00:14:34 2003
@@ -333,7 +333,7 @@
for (bytes = 0, p = buf; bytes < len; bytes += n, p+=n) {
n = sys_getdents64(fd, p, len - bytes);
if (n < 0)
- return -1;
+ return n;
if (n == 0)
return bytes;
}
@@ -361,7 +361,7 @@
return p;
}
kfree(p);
- if (n < 0)
+ if (n < 0 && n != -EINVAL)
break;
}
close(fd);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] fix CONFIG_DEVFS=y root=<number> 2003-01-04 8:01 [PATCH] fix CONFIG_DEVFS=y root=<number> Milton Miller @ 2003-01-04 8:36 ` Andrew Morton 2003-01-05 7:46 ` Milton Miller 0 siblings, 1 reply; 3+ messages in thread From: Andrew Morton @ 2003-01-04 8:36 UTC (permalink / raw) To: Milton Miller; +Cc: linux-kernel, Helge Hafting Milton Miller wrote: > > Based on a patch by Adam J. Richter <adam@yggdrasil.com> [1], this fixes > the problem since 2.5.47 with mounting a devfs=y system with root=<number> > > sys_get_dents64 returns -EINVAL if there is not space for an entry, so > we need to activate the loop code to expand the buffer. > Yes, I agree. argh, why did you make me look at that code. I really shouldn't do this, but I can't help myself! How does this look? Patch from Milton Miller <miltonm@bga.com> There's some init-time code which is supposed to read a devfs directory by expanding the bufer until the whole directory fits. But the logic is wrong and it only works if the whole directory fits into 512 bytes. So fix that up, and also clean up some coding in there, and rationalise the duplicated definition of linux_dirent64. fs/readdir.c | 12 +----------- include/linux/dirent.h | 13 +++++++++++++ init/do_mounts.c | 29 +++++++++++++++++------------ 3 files changed, 31 insertions(+), 23 deletions(-) --- 25/init/do_mounts.c~devfs-mount-fix Sat Jan 4 00:19:53 2003 +++ 25-akpm/init/do_mounts.c Sat Jan 4 00:33:39 2003 @@ -13,6 +13,7 @@ #include <linux/suspend.h> #include <linux/root_dev.h> #include <linux/mount.h> +#include <linux/dirent.h> #include <linux/security.h> #include <linux/nfs_fs.h> @@ -324,22 +325,32 @@ static int __init mount_nfs_root(void) #endif #ifdef CONFIG_DEVFS_FS + +/* + * If the dir will fit in *buf, return its length. If it won't fit, return + * zero. Return -ve on error. + */ static int __init do_read_dir(int fd, void *buf, int len) { long bytes, n; char *p = buf; lseek(fd, 0, 0); - for (bytes = 0, p = buf; bytes < len; bytes += n, p+=n) { - n = sys_getdents64(fd, p, len - bytes); + for (bytes = 0; bytes < len; bytes += n) { + n = sys_getdents64(fd, p + n, len - bytes); if (n < 0) - return -1; + return n; if (n == 0) return bytes; } return 0; } +/* + * Try to read all of a directory. Returns the contents at *p, which + * is kmalloced memory. Returns the number of bytes read at *len. Returns + * NULL on error. + */ static void * __init read_dir(char *path, int *len) { int size; @@ -349,7 +360,7 @@ static void * __init read_dir(char *path if (fd < 0) return NULL; - for (size = 1<<9; size < (1<<18); size <<= 1) { + for (size = 1 << 9; size <= (1 << MAX_ORDER); size <<= 1) { void *p = kmalloc(size, GFP_KERNEL); int n; if (!p) @@ -361,6 +372,8 @@ static void * __init read_dir(char *path return p; } kfree(p); + if (n == -EINVAL) + continue; /* Try a larger buffer */ if (n < 0) break; } @@ -369,14 +382,6 @@ static void * __init read_dir(char *path } #endif -struct linux_dirent64 { - u64 d_ino; - s64 d_off; - unsigned short d_reclen; - unsigned char d_type; - char d_name[0]; -}; - static int __init find_in_devfs(char *path, dev_t dev) { #ifdef CONFIG_DEVFS_FS --- 25/include/linux/dirent.h~devfs-mount-fix Sat Jan 4 00:20:21 2003 +++ 25-akpm/include/linux/dirent.h Sat Jan 4 00:20:56 2003 @@ -16,4 +16,17 @@ struct dirent64 { char d_name[256]; }; +#ifdef __KERNEL__ + +struct linux_dirent64 { + u64 d_ino; + s64 d_off; + unsigned short d_reclen; + unsigned char d_type; + char d_name[0]; +}; + +#endif /* __KERNEL__ */ + + #endif --- 25/fs/readdir.c~devfs-mount-fix Sat Jan 4 00:21:11 2003 +++ 25-akpm/fs/readdir.c Sat Jan 4 00:28:08 2003 @@ -11,6 +11,7 @@ #include <linux/file.h> #include <linux/smp_lock.h> #include <linux/fs.h> +#include <linux/dirent.h> #include <linux/security.h> #include <asm/uaccess.h> @@ -194,17 +195,6 @@ out: return error; } -/* - * And even better one including d_type field and 64bit d_ino and d_off. - */ -struct linux_dirent64 { - u64 d_ino; - s64 d_off; - unsigned short d_reclen; - unsigned char d_type; - char d_name[0]; -}; - #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) struct getdents_callback64 { _ ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] fix CONFIG_DEVFS=y root=<number> 2003-01-04 8:36 ` Andrew Morton @ 2003-01-05 7:46 ` Milton Miller 0 siblings, 0 replies; 3+ messages in thread From: Milton Miller @ 2003-01-05 7:46 UTC (permalink / raw) To: Andrew Morton; +Cc: linux-kernel init/do_mounts.c: In function `do_read_dir': init/do_mounts.c:335: warning: `n' might be used uninitialized in this function and it loops trying to intrepret the directory listing :( After some searching, I realized the directory contents read in were garbage, looked at that code closer, and found the cause of the problem: for (bytes = 0; bytes < len; bytes += n) { - n = sys_getdents64(fd, p + n, len - bytes); + n = sys_getdents64(fd, p + bytes, len - bytes); updated patch below: # Patch from Milton Miller <miltonm@bga.com> # Based on discovery work by Adam J. Richter <adam@yggdrasil.com> # Cleanups by Andrew Morton (akpm@digeo.com) # # There's some init-time code which is supposed to read a devfs directory by # expanding the bufer until the whole directory fits. But the logic is wrong # and it only works if the whole directory fits into 512 bytes. # # So fix that up, and also clean up some coding in there, and rationalise the # duplicated definition of linux_dirent64. # -------------------------------------------- # diff -Nru a/fs/readdir.c b/fs/readdir.c --- a/fs/readdir.c Sun Jan 5 01:35:40 2003 +++ b/fs/readdir.c Sun Jan 5 01:35:40 2003 @@ -11,6 +11,7 @@ #include <linux/file.h> #include <linux/smp_lock.h> #include <linux/fs.h> +#include <linux/dirent.h> #include <linux/security.h> #include <asm/uaccess.h> @@ -193,17 +194,6 @@ out: return error; } - -/* - * And even better one including d_type field and 64bit d_ino and d_off. - */ -struct linux_dirent64 { - u64 d_ino; - s64 d_off; - unsigned short d_reclen; - unsigned char d_type; - char d_name[0]; -}; #define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) diff -Nru a/include/linux/dirent.h b/include/linux/dirent.h --- a/include/linux/dirent.h Sun Jan 5 01:35:40 2003 +++ b/include/linux/dirent.h Sun Jan 5 01:35:40 2003 @@ -16,4 +16,17 @@ char d_name[256]; }; +#ifdef __KERNEL__ + +struct linux_dirent64 { + u64 d_ino; + s64 d_off; + unsigned short d_reclen; + unsigned char d_type; + char d_name[0]; +}; + +#endif /* __KERNEL__ */ + + #endif diff -Nru a/init/do_mounts.c b/init/do_mounts.c --- a/init/do_mounts.c Sun Jan 5 01:35:40 2003 +++ b/init/do_mounts.c Sun Jan 5 01:35:40 2003 @@ -13,6 +13,7 @@ #include <linux/suspend.h> #include <linux/root_dev.h> #include <linux/mount.h> +#include <linux/dirent.h> #include <linux/security.h> #include <linux/nfs_fs.h> @@ -324,22 +325,32 @@ #endif #ifdef CONFIG_DEVFS_FS + +/* + * If the dir will fit in *buf, return its length. If it won't fit, return + * zero. Return -ve on error. + */ static int __init do_read_dir(int fd, void *buf, int len) { long bytes, n; char *p = buf; lseek(fd, 0, 0); - for (bytes = 0, p = buf; bytes < len; bytes += n, p+=n) { - n = sys_getdents64(fd, p, len - bytes); + for (bytes = 0; bytes < len; bytes += n) { + n = sys_getdents64(fd, p + bytes, len - bytes); if (n < 0) - return -1; + return n; if (n == 0) return bytes; } return 0; } +/* + * Try to read all of a directory. Returns the contents at *p, which + * is kmalloced memory. Returns the number of bytes read at *len. Returns + * NULL on error. + */ static void * __init read_dir(char *path, int *len) { int size; @@ -349,7 +360,7 @@ if (fd < 0) return NULL; - for (size = 1<<9; size < (1<<18); size <<= 1) { + for (size = 1 << 9; size <= (1 << MAX_ORDER); size <<= 1) { void *p = kmalloc(size, GFP_KERNEL); int n; if (!p) @@ -361,6 +372,8 @@ return p; } kfree(p); + if (n == -EINVAL) + continue; /* Try a larger buffer */ if (n < 0) break; } @@ -368,14 +381,6 @@ return NULL; } #endif - -struct linux_dirent64 { - u64 d_ino; - s64 d_off; - unsigned short d_reclen; - unsigned char d_type; - char d_name[0]; -}; static int __init find_in_devfs(char *path, dev_t dev) { ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2003-01-05 7:38 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2003-01-04 8:01 [PATCH] fix CONFIG_DEVFS=y root=<number> Milton Miller 2003-01-04 8:36 ` Andrew Morton 2003-01-05 7:46 ` Milton Miller
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