* [PATCH v3] mtd: Do not corrupt backing device of device node inode
@ 2010-05-05 8:21 ` Kirill A. Shutemov
0 siblings, 0 replies; 7+ messages in thread
From: Kirill A. Shutemov @ 2010-05-05 8:21 UTC (permalink / raw)
To: David Woodhouse
Cc: Jan Kara, Alexander Viro, David Howells, Alexander Shishkin,
Artem Bityutskiy, linux-mtd, linux-fsdevel, linux-kernel,
Kirill A. Shutemov
We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
backing device of device node inode, since file->f_mapping is equal to
inode->i_mapping (see __dentry_open() in fs/open.c).
Let's introduce separate inode for MTD device with appropriate backing
device.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Jan Kara <jack@suse.cz>
---
Changelog
v2 -> v3:
- Rebase to mtd.git.
v1 -> v2:
- Fix error handling based on comments by Jan Kara.
---
drivers/mtd/mtdchar.c | 77 ++++++++++++++++++++++++++++++++++++++++++-----
drivers/mtd/mtdcore.c | 3 ++
include/linux/mtd/mtd.h | 3 ++
3 files changed, 75 insertions(+), 8 deletions(-)
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index c355491..a2bb3ce 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -15,12 +15,15 @@
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/compat.h>
+#include <linux/mount.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/compatmac.h>
#include <asm/uaccess.h>
+#define MTD_INODE_FS_MAGIC 0x11307854
+static struct vfsmount *mtd_inode_mnt __read_mostly;
/*
* Data structure to hold the pointer to the mtd device as well
@@ -85,11 +88,30 @@ static int mtd_open(struct inode *inode, struct file *file)
goto out;
}
- if (mtd->backing_dev_info)
- file->f_mapping->backing_dev_info = mtd->backing_dev_info;
+ if (!mtd->inode) {
+ mtd->inode = new_inode(mtd_inode_mnt->mnt_sb);
+ if (!mtd->inode) {
+ put_mtd_device(mtd);
+ ret = -ENOMEM;
+ goto out;
+ }
+ mtd->inode->i_mode = S_IFCHR;
+ mtd->inode->i_rdev = inode->i_rdev;
+ if (mtd->backing_dev_info) {
+ mtd->inode->i_data.backing_dev_info =
+ mtd->backing_dev_info;
+ }
+ }
+
+ spin_lock(&inode_lock);
+ __iget(mtd->inode);
+ spin_unlock(&inode_lock);
+
+ file->f_mapping = mtd->inode->i_mapping;
/* You can't open it RW if it's not a writeable device */
if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
+ iput(mtd->inode);
put_mtd_device(mtd);
ret = -EACCES;
goto out;
@@ -97,6 +119,7 @@ static int mtd_open(struct inode *inode, struct file *file)
mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
if (!mfi) {
+ iput(mtd->inode);
put_mtd_device(mtd);
ret = -ENOMEM;
goto out;
@@ -122,6 +145,8 @@ static int mtd_close(struct inode *inode, struct file *file)
if ((file->f_mode & FMODE_WRITE) && mtd->sync)
mtd->sync(mtd);
+ iput(mtd->inode);
+
put_mtd_device(mtd);
file->private_data = NULL;
kfree(mfi);
@@ -951,22 +976,58 @@ static const struct file_operations mtd_fops = {
#endif
};
+static int mtd_inodefs_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data,
+ struct vfsmount *mnt)
+{
+ return get_sb_pseudo(fs_type, "mtd_inode:", NULL, MTD_INODE_FS_MAGIC,
+ mnt);
+}
+
+static struct file_system_type mtd_inodefs_type = {
+ .name = "mtd_inodefs",
+ .get_sb = mtd_inodefs_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
static int __init init_mtdchar(void)
{
- int status;
+ int ret;
- status = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
+ ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
"mtd", &mtd_fops);
- if (status < 0) {
- printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
- MTD_CHAR_MAJOR);
+ if (ret < 0) {
+ pr_notice("Can't allocate major number %d for "
+ "Memory Technology Devices.\n", MTD_CHAR_MAJOR);
+ return ret;
+ }
+
+ ret = register_filesystem(&mtd_inodefs_type);
+ if (ret) {
+ pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
+ goto err_unregister_chdev;
}
- return status;
+ mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
+ if (IS_ERR(mtd_inode_mnt)) {
+ ret = PTR_ERR(mtd_inode_mnt);
+ pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
+ goto err_unregister_filesystem;
+ }
+
+ return ret;
+
+err_unregister_filesystem:
+ unregister_filesystem(&mtd_inodefs_type);
+err_unregister_chdev:
+ unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
+ return ret;
}
static void __exit cleanup_mtdchar(void)
{
+ mntput(mtd_inode_mnt);
+ unregister_filesystem(&mtd_inodefs_type);
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
}
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 70a7858..fa424ad 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -369,6 +369,9 @@ int del_mtd_device (struct mtd_info *mtd)
mtd->index, mtd->name, mtd->usecount);
ret = -EBUSY;
} else {
+ if (mtd->inode)
+ iput(mtd->inode);
+
device_unregister(&mtd->dev);
idr_remove(&mtd_idr, mtd->index);
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 5326435..d66409a 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -12,6 +12,7 @@
#include <linux/uio.h>
#include <linux/notifier.h>
#include <linux/device.h>
+#include <linux/fs.h>
#include <linux/mtd/compatmac.h>
#include <mtd/mtd-abi.h>
@@ -174,6 +175,8 @@ struct mtd_info {
*/
struct backing_dev_info *backing_dev_info;
+ /* inode for mtd device */
+ struct inode *inode;
int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
--
1.7.0.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v3] mtd: Do not corrupt backing device of device node inode
@ 2010-05-05 8:21 ` Kirill A. Shutemov
0 siblings, 0 replies; 7+ messages in thread
From: Kirill A. Shutemov @ 2010-05-05 8:21 UTC (permalink / raw)
To: David Woodhouse
Cc: Jan Kara, Artem Bityutskiy, linux-kernel, David Howells,
Alexander Shishkin, linux-mtd, Alexander Viro, linux-fsdevel,
Kirill A. Shutemov
We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
backing device of device node inode, since file->f_mapping is equal to
inode->i_mapping (see __dentry_open() in fs/open.c).
Let's introduce separate inode for MTD device with appropriate backing
device.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Jan Kara <jack@suse.cz>
---
Changelog
v2 -> v3:
- Rebase to mtd.git.
v1 -> v2:
- Fix error handling based on comments by Jan Kara.
---
drivers/mtd/mtdchar.c | 77 ++++++++++++++++++++++++++++++++++++++++++-----
drivers/mtd/mtdcore.c | 3 ++
include/linux/mtd/mtd.h | 3 ++
3 files changed, 75 insertions(+), 8 deletions(-)
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index c355491..a2bb3ce 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -15,12 +15,15 @@
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/compat.h>
+#include <linux/mount.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/compatmac.h>
#include <asm/uaccess.h>
+#define MTD_INODE_FS_MAGIC 0x11307854
+static struct vfsmount *mtd_inode_mnt __read_mostly;
/*
* Data structure to hold the pointer to the mtd device as well
@@ -85,11 +88,30 @@ static int mtd_open(struct inode *inode, struct file *file)
goto out;
}
- if (mtd->backing_dev_info)
- file->f_mapping->backing_dev_info = mtd->backing_dev_info;
+ if (!mtd->inode) {
+ mtd->inode = new_inode(mtd_inode_mnt->mnt_sb);
+ if (!mtd->inode) {
+ put_mtd_device(mtd);
+ ret = -ENOMEM;
+ goto out;
+ }
+ mtd->inode->i_mode = S_IFCHR;
+ mtd->inode->i_rdev = inode->i_rdev;
+ if (mtd->backing_dev_info) {
+ mtd->inode->i_data.backing_dev_info =
+ mtd->backing_dev_info;
+ }
+ }
+
+ spin_lock(&inode_lock);
+ __iget(mtd->inode);
+ spin_unlock(&inode_lock);
+
+ file->f_mapping = mtd->inode->i_mapping;
/* You can't open it RW if it's not a writeable device */
if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
+ iput(mtd->inode);
put_mtd_device(mtd);
ret = -EACCES;
goto out;
@@ -97,6 +119,7 @@ static int mtd_open(struct inode *inode, struct file *file)
mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
if (!mfi) {
+ iput(mtd->inode);
put_mtd_device(mtd);
ret = -ENOMEM;
goto out;
@@ -122,6 +145,8 @@ static int mtd_close(struct inode *inode, struct file *file)
if ((file->f_mode & FMODE_WRITE) && mtd->sync)
mtd->sync(mtd);
+ iput(mtd->inode);
+
put_mtd_device(mtd);
file->private_data = NULL;
kfree(mfi);
@@ -951,22 +976,58 @@ static const struct file_operations mtd_fops = {
#endif
};
+static int mtd_inodefs_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data,
+ struct vfsmount *mnt)
+{
+ return get_sb_pseudo(fs_type, "mtd_inode:", NULL, MTD_INODE_FS_MAGIC,
+ mnt);
+}
+
+static struct file_system_type mtd_inodefs_type = {
+ .name = "mtd_inodefs",
+ .get_sb = mtd_inodefs_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
static int __init init_mtdchar(void)
{
- int status;
+ int ret;
- status = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
+ ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
"mtd", &mtd_fops);
- if (status < 0) {
- printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
- MTD_CHAR_MAJOR);
+ if (ret < 0) {
+ pr_notice("Can't allocate major number %d for "
+ "Memory Technology Devices.\n", MTD_CHAR_MAJOR);
+ return ret;
+ }
+
+ ret = register_filesystem(&mtd_inodefs_type);
+ if (ret) {
+ pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
+ goto err_unregister_chdev;
}
- return status;
+ mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
+ if (IS_ERR(mtd_inode_mnt)) {
+ ret = PTR_ERR(mtd_inode_mnt);
+ pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
+ goto err_unregister_filesystem;
+ }
+
+ return ret;
+
+err_unregister_filesystem:
+ unregister_filesystem(&mtd_inodefs_type);
+err_unregister_chdev:
+ unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
+ return ret;
}
static void __exit cleanup_mtdchar(void)
{
+ mntput(mtd_inode_mnt);
+ unregister_filesystem(&mtd_inodefs_type);
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
}
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 70a7858..fa424ad 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -369,6 +369,9 @@ int del_mtd_device (struct mtd_info *mtd)
mtd->index, mtd->name, mtd->usecount);
ret = -EBUSY;
} else {
+ if (mtd->inode)
+ iput(mtd->inode);
+
device_unregister(&mtd->dev);
idr_remove(&mtd_idr, mtd->index);
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 5326435..d66409a 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -12,6 +12,7 @@
#include <linux/uio.h>
#include <linux/notifier.h>
#include <linux/device.h>
+#include <linux/fs.h>
#include <linux/mtd/compatmac.h>
#include <mtd/mtd-abi.h>
@@ -174,6 +175,8 @@ struct mtd_info {
*/
struct backing_dev_info *backing_dev_info;
+ /* inode for mtd device */
+ struct inode *inode;
int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
--
1.7.0.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v3] mtd: Do not corrupt backing device of device node inode
2010-05-05 8:21 ` Kirill A. Shutemov
(?)
@ 2010-05-05 14:17 ` Artem Bityutskiy
-1 siblings, 0 replies; 7+ messages in thread
From: Artem Bityutskiy @ 2010-05-05 14:17 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: David Woodhouse, Jan Kara, Alexander Viro, David Howells,
Alexander Shishkin, linux-mtd, linux-fsdevel, linux-kernel
On Wed, 2010-05-05 at 11:21 +0300, Kirill A. Shutemov wrote:
> We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
> backing device of device node inode, since file->f_mapping is equal to
> inode->i_mapping (see __dentry_open() in fs/open.c).
>
> Let's introduce separate inode for MTD device with appropriate backing
> device.
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> Acked-by: Jan Kara <jack@suse.cz>
I get the following build error:
[dedekind@eru l2-mtd-2.6]$ make -j8
O=/home/dedekind/tmp/l2-mtd-2.6-x86_64/
GEN /home/dedekind/tmp/l2-mtd-2.6-x86_64/Makefile
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Using /home/dedekind/git/l2-mtd-2.6 as source for kernel
CALL /home/dedekind/git/l2-mtd-2.6/scripts/checksyscalls.sh
CHK include/generated/compile.h
CHK include/linux/version.h
make[3]: `scripts/unifdef' is up to date.
Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready (#2)
MODPOST 146 modules
ERROR: "__iget" [drivers/mtd/mtdchar.ko] undefined!
ERROR: "inode_lock" [drivers/mtd/mtdchar.ko] undefined!
make[2]: *** [__modpost] Error 1
make[1]: *** [modules] Error 2
make: *** [sub-make] Error 2
__iget and inode_lock are not exported...
--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] mtd: Do not corrupt backing device of device node inode
@ 2010-05-05 14:17 ` Artem Bityutskiy
0 siblings, 0 replies; 7+ messages in thread
From: Artem Bityutskiy @ 2010-05-05 14:17 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: David Woodhouse, Jan Kara, Alexander Viro, David Howells,
Alexander Shishkin, linux-mtd, linux-fsdevel, linux-kernel
On Wed, 2010-05-05 at 11:21 +0300, Kirill A. Shutemov wrote:
> We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
> backing device of device node inode, since file->f_mapping is equal to
> inode->i_mapping (see __dentry_open() in fs/open.c).
>
> Let's introduce separate inode for MTD device with appropriate backing
> device.
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> Acked-by: Jan Kara <jack@suse.cz>
I get the following build error:
[dedekind@eru l2-mtd-2.6]$ make -j8
O=/home/dedekind/tmp/l2-mtd-2.6-x86_64/
GEN /home/dedekind/tmp/l2-mtd-2.6-x86_64/Makefile
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Using /home/dedekind/git/l2-mtd-2.6 as source for kernel
CALL /home/dedekind/git/l2-mtd-2.6/scripts/checksyscalls.sh
CHK include/generated/compile.h
CHK include/linux/version.h
make[3]: `scripts/unifdef' is up to date.
Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready (#2)
MODPOST 146 modules
ERROR: "__iget" [drivers/mtd/mtdchar.ko] undefined!
ERROR: "inode_lock" [drivers/mtd/mtdchar.ko] undefined!
make[2]: *** [__modpost] Error 1
make[1]: *** [modules] Error 2
make: *** [sub-make] Error 2
__iget and inode_lock are not exported...
--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] mtd: Do not corrupt backing device of device node inode
@ 2010-05-05 14:17 ` Artem Bityutskiy
0 siblings, 0 replies; 7+ messages in thread
From: Artem Bityutskiy @ 2010-05-05 14:17 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Jan Kara, linux-kernel, David Howells, Alexander Shishkin,
linux-mtd, Alexander Viro, linux-fsdevel, David Woodhouse
On Wed, 2010-05-05 at 11:21 +0300, Kirill A. Shutemov wrote:
> We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
> backing device of device node inode, since file->f_mapping is equal to
> inode->i_mapping (see __dentry_open() in fs/open.c).
>
> Let's introduce separate inode for MTD device with appropriate backing
> device.
>
> Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> Acked-by: Jan Kara <jack@suse.cz>
I get the following build error:
[dedekind@eru l2-mtd-2.6]$ make -j8
O=/home/dedekind/tmp/l2-mtd-2.6-x86_64/
GEN /home/dedekind/tmp/l2-mtd-2.6-x86_64/Makefile
CHK include/linux/version.h
CHK include/generated/utsrelease.h
Using /home/dedekind/git/l2-mtd-2.6 as source for kernel
CALL /home/dedekind/git/l2-mtd-2.6/scripts/checksyscalls.sh
CHK include/generated/compile.h
CHK include/linux/version.h
make[3]: `scripts/unifdef' is up to date.
Building modules, stage 2.
Kernel: arch/x86/boot/bzImage is ready (#2)
MODPOST 146 modules
ERROR: "__iget" [drivers/mtd/mtdchar.ko] undefined!
ERROR: "inode_lock" [drivers/mtd/mtdchar.ko] undefined!
make[2]: *** [__modpost] Error 1
make[1]: *** [modules] Error 2
make: *** [sub-make] Error 2
__iget and inode_lock are not exported...
--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] mtd: Do not corrupt backing device of device node inode
2010-05-05 14:17 ` Artem Bityutskiy
@ 2010-05-05 14:27 ` Jan Kara
-1 siblings, 0 replies; 7+ messages in thread
From: Jan Kara @ 2010-05-05 14:27 UTC (permalink / raw)
To: Artem Bityutskiy
Cc: Kirill A. Shutemov, David Woodhouse, Jan Kara, Alexander Viro,
David Howells, Alexander Shishkin, linux-mtd, linux-fsdevel,
linux-kernel
On Wed 05-05-10 17:17:19, Artem Bityutskiy wrote:
> On Wed, 2010-05-05 at 11:21 +0300, Kirill A. Shutemov wrote:
> > We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
> > backing device of device node inode, since file->f_mapping is equal to
> > inode->i_mapping (see __dentry_open() in fs/open.c).
> >
> > Let's introduce separate inode for MTD device with appropriate backing
> > device.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> > Acked-by: Jan Kara <jack@suse.cz>
>
> I get the following build error:
>
> [dedekind@eru l2-mtd-2.6]$ make -j8
> O=/home/dedekind/tmp/l2-mtd-2.6-x86_64/
> GEN /home/dedekind/tmp/l2-mtd-2.6-x86_64/Makefile
> CHK include/linux/version.h
> CHK include/generated/utsrelease.h
> Using /home/dedekind/git/l2-mtd-2.6 as source for kernel
> CALL /home/dedekind/git/l2-mtd-2.6/scripts/checksyscalls.sh
> CHK include/generated/compile.h
> CHK include/linux/version.h
> make[3]: `scripts/unifdef' is up to date.
> Building modules, stage 2.
> Kernel: arch/x86/boot/bzImage is ready (#2)
> MODPOST 146 modules
> ERROR: "__iget" [drivers/mtd/mtdchar.ko] undefined!
> ERROR: "inode_lock" [drivers/mtd/mtdchar.ko] undefined!
> make[2]: *** [__modpost] Error 1
> make[1]: *** [modules] Error 2
> make: *** [sub-make] Error 2
>
> __iget and inode_lock are not exported...
Ah, right. igrab() should be used instead of __iget inside the
inode_lock.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] mtd: Do not corrupt backing device of device node inode
@ 2010-05-05 14:27 ` Jan Kara
0 siblings, 0 replies; 7+ messages in thread
From: Jan Kara @ 2010-05-05 14:27 UTC (permalink / raw)
To: Artem Bityutskiy
Cc: Jan Kara, linux-kernel, David Howells, Alexander Shishkin,
linux-mtd, Alexander Viro, linux-fsdevel, Kirill A. Shutemov,
David Woodhouse
On Wed 05-05-10 17:17:19, Artem Bityutskiy wrote:
> On Wed, 2010-05-05 at 11:21 +0300, Kirill A. Shutemov wrote:
> > We cannot modify file->f_mapping->backing_dev_info, because it will corrupt
> > backing device of device node inode, since file->f_mapping is equal to
> > inode->i_mapping (see __dentry_open() in fs/open.c).
> >
> > Let's introduce separate inode for MTD device with appropriate backing
> > device.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
> > Acked-by: Jan Kara <jack@suse.cz>
>
> I get the following build error:
>
> [dedekind@eru l2-mtd-2.6]$ make -j8
> O=/home/dedekind/tmp/l2-mtd-2.6-x86_64/
> GEN /home/dedekind/tmp/l2-mtd-2.6-x86_64/Makefile
> CHK include/linux/version.h
> CHK include/generated/utsrelease.h
> Using /home/dedekind/git/l2-mtd-2.6 as source for kernel
> CALL /home/dedekind/git/l2-mtd-2.6/scripts/checksyscalls.sh
> CHK include/generated/compile.h
> CHK include/linux/version.h
> make[3]: `scripts/unifdef' is up to date.
> Building modules, stage 2.
> Kernel: arch/x86/boot/bzImage is ready (#2)
> MODPOST 146 modules
> ERROR: "__iget" [drivers/mtd/mtdchar.ko] undefined!
> ERROR: "inode_lock" [drivers/mtd/mtdchar.ko] undefined!
> make[2]: *** [__modpost] Error 1
> make[1]: *** [modules] Error 2
> make: *** [sub-make] Error 2
>
> __iget and inode_lock are not exported...
Ah, right. igrab() should be used instead of __iget inside the
inode_lock.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2010-05-05 14:27 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-05-05 8:21 [PATCH v3] mtd: Do not corrupt backing device of device node inode Kirill A. Shutemov
2010-05-05 8:21 ` Kirill A. Shutemov
2010-05-05 14:17 ` Artem Bityutskiy
2010-05-05 14:17 ` Artem Bityutskiy
2010-05-05 14:17 ` Artem Bityutskiy
2010-05-05 14:27 ` Jan Kara
2010-05-05 14:27 ` Jan Kara
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