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Date: Tue, 9 Sep 2008 21:58:14 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: Theodore Tso <tytso@....EDU>
Cc: Christoph Hellwig <hch@...radead.org>, adilger@....com,
linux-ext4@...r.kernel.org
Subject: Re: [PATCH] Add extent conversion support to chattr
On Tue, Sep 09, 2008 at 10:39:15AM -0400, Theodore Tso wrote:
> On Tue, Sep 09, 2008 at 07:39:29PM +0530, Aneesh Kumar K.V wrote:
> >
> > Shouldn't other file system give error when we call an ioctl with
> > EXT4_IOC_MIGRATE on the fd ?
>
> Only if by some incredible bad luck the ioctl number (which is after
> all only at 16 bit number) doesn't happen to do something else random,
> like security erase the entire filesystem. :-)
>
> > On ext3 I get the below error
> > [an/chattr@...sprogs-upstream-build]$ ./misc/chattr -E ./misc/e2undo
> > ./misc/chattr: Inappropriate ioctl for device while converting ./misc/e2undo to extent format
> >
>
> #1, it really should be +e, since we are turning on the extent flag,
> and #2, we should give a much more user-understandable error message
> in that case.
something like
From: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH] Add extent conversion support to chattr
This patch adds new option, +e to chattr. The +e option
is used to convert the ext3 format (non extent) file
to ext4 (extent) format. This can be used to migrate
the ext3 file system to ext4 file system.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
lib/e2p/e2p.h | 1 +
lib/e2p/fsetflags.c | 10 ++++++++++
lib/ext2fs/ext2_fs.h | 1 +
misc/chattr.1.in | 9 ++++-----
misc/chattr.c | 17 ++++++++++++++++-
5 files changed, 32 insertions(+), 6 deletions(-)
diff --git a/lib/e2p/e2p.h b/lib/e2p/e2p.h
index 98c97db..8cbf360 100644
--- a/lib/e2p/e2p.h
+++ b/lib/e2p/e2p.h
@@ -60,3 +60,4 @@ char *e2p_os2string(int os_type);
int e2p_string2os(char *str);
unsigned int e2p_percent(int percent, unsigned int base);
+int ext4_migrate(const char * name);
diff --git a/lib/e2p/fsetflags.c b/lib/e2p/fsetflags.c
index 62189c9..d1bb9d9 100644
--- a/lib/e2p/fsetflags.c
+++ b/lib/e2p/fsetflags.c
@@ -80,9 +80,19 @@ int fsetflags (const char * name, unsigned long flags)
if (fd == -1)
return -1;
f = (int) flags;
+ if (f & EXT4_EXTENTS_FL) {
+ /* extent flags is set using migrate ioctl */
+ r = ioctl (fd, EXT4_IOC_MIGRATE, NULL);
+ if (r == -1) {
+ save_errno = errno;
+ goto err_out;
+ }
+ f = (int)flags & ~EXT4_EXTENTS_FL;
+ }
r = ioctl (fd, EXT2_IOC_SETFLAGS, &f);
if (r == -1)
save_errno = errno;
+err_out:
close (fd);
if (save_errno)
errno = save_errno;
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index d7d7bdb..2fe6691 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -316,6 +316,7 @@ struct ext4_new_group_input {
#define EXT2_IOC_GROUP_EXTEND _IOW('f', 7, unsigned long)
#define EXT2_IOC_GROUP_ADD _IOW('f', 8,struct ext2_new_group_input)
#define EXT4_IOC_GROUP_ADD _IOW('f', 8,struct ext4_new_group_input)
+#define EXT4_IOC_MIGRATE _IO('f', 7)
/*
* Structure of an inode on the disk
diff --git a/misc/chattr.1.in b/misc/chattr.1.in
index 960f058..1247090 100644
--- a/misc/chattr.1.in
+++ b/misc/chattr.1.in
@@ -19,7 +19,7 @@ chattr \- change file attributes on a Linux second extended file system
.B chattr
changes the file attributes on a Linux second extended file system.
.PP
-The format of a symbolic mode is +-=[ASacDdIijsTtu].
+The format of a symbolic mode is +-=[ASacDdIijsTtue].
.PP
The operator `+' causes the selected attributes to be added to the
existing attributes of the files; `-' causes them to be removed; and
@@ -74,10 +74,9 @@ although it can be displayed by
.BR lsattr (1).
.PP
The 'e' attribute indicates that the file is using extents for mapping
-the blocks on disk. It may not be set or reset using
-.BR chattr (1),
-although it can be displayed by
-.BR lsattr (1).
+the blocks on disk. Setting extent flag cause the file to be converted
+to extent format. It may not be unset using
+.BR chattr (1).
.PP
The 'I' attribute is used by the htree code to indicate that a directory
is being indexed using hashed trees. It may not be set or reset using
diff --git a/misc/chattr.c b/misc/chattr.c
index 3d67519..c9d6d1e 100644
--- a/misc/chattr.c
+++ b/misc/chattr.c
@@ -82,7 +82,7 @@ static unsigned long sf;
static void usage(void)
{
fprintf(stderr,
- _("Usage: %s [-RVf] [-+=AacDdijsSu] [-v version] files...\n"),
+ _("Usage: %s [-RVf] [-+=AacDdijsSu] [+e] [-v version] files...\n"),
program_name);
exit(1);
}
@@ -105,6 +105,7 @@ static const struct flags_char flags_array[] = {
{ EXT2_UNRM_FL, 'u' },
{ EXT2_NOTAIL_FL, 't' },
{ EXT2_TOPDIR_FL, 'T' },
+ { EXT4_EXTENTS_FL, 'e'},
{ 0, 0 }
};
@@ -199,6 +200,20 @@ static int change_attributes(const char * name)
return -1;
}
+ if (rf & EXT4_EXTENTS_FL) {
+ /* only allowed format is +e */
+ com_err (program_name, errno,
+ _("Cannot remove the extent flag on %s"), name);
+ return -1;
+ }
+
+ if (sf & EXT4_EXTENTS_FL) {
+ /* only allowed format is +e */
+ com_err (program_name, errno,
+ _("Extent flag cannot be the only attribute on %s"), name);
+ return -1;
+ }
+
if (set) {
if (verbose) {
printf (_("Flags of %s set as "), name);
--
tg: (5bf3f80..) an/chattr (depends on: master)
--
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