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Message-Id: <1477073814-27482-1-git-send-email-fabf@skynet.be>
Date: Fri, 21 Oct 2016 20:16:54 +0200
From: Fabian Frederick <fabf@...net.be>
To: tytso@....edu
Cc: Andreas Dilger <adilger.kernel@...ger.ca>,
linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org,
fabf@...net.be
Subject: [PATCH V2 linux-next] ext4: make online resizing conditional
This patch tries to address the following comment in ext4/resize.c
"This could probably be made into a module, because it is not often in use."
Having ext4 resizing in a module would give a lot of depmod
dependency cycles but we can make it an option.
resize.h has been added for more readability.
Tried the following resizing:
dd if=/dev/zero of=ddext4 bs=1M count=100
losetup -f ddext4
mkfs -t ext4 /dev/loop0
losetup -D
dd if=/dev/zero of=ddappend bs=1M count=50
cat ddappend >> ddext4
losetup -f ddext4
mount /dev/loop0 /mnt
resize2fs /dev/loop0
With option disabled:
"Operation not supported While checking for on-line resizing support"
Signed-off-by: Fabian Frederick <fabf@...net.be>
---
V2:
-Fix checkpatch warnings on identifier names like:
WARNING: function definition argument 'struct super_block *'
should also have an identifier name
#130: FILE: fs/ext4/resize.h:8:
+extern int ext4_resize_fs(struct super_block *, ext4_fsblk_t);
-Reorder extern functions in resize.h to match -EOPNOTSUPP definitions
-Rename EXT4_RESIZING to EXT4_RESIZING_ACTIVE
(Andreas Dilger suggested EXT4_RESIZE_ACTIVE but we already have
EXT4_RESIZE_INO in another context)
Other suggestions by Andreas:
-Add comment to s_resize_flags for EXT4_RESIZING_* bits
-Leave the module comment in resize.h
-Use ifdef CONFIG instead of IS_ENABLED()
fs/ext4/Kconfig | 7 +++++++
fs/ext4/Makefile | 3 ++-
fs/ext4/ext4.h | 16 +++-------------
fs/ext4/ioctl.c | 1 +
fs/ext4/resize.c | 6 ++++--
fs/ext4/resize.h | 42 ++++++++++++++++++++++++++++++++++++++++++
6 files changed, 59 insertions(+), 16 deletions(-)
create mode 100644 fs/ext4/resize.h
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index e38039f..2ec35c3 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -122,3 +122,10 @@ config EXT4_DEBUG
If you select Y here, then you will be able to turn on debugging
with a command such as:
echo 1 > /sys/module/ext4/parameters/mballoc_debug
+
+config EXT4_RESIZE
+ bool "EXT4 resize"
+ depends on EXT4_FS
+ default y
+ help
+ Support online ext4 partition resizing.
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 354103f..efe6579 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -5,10 +5,11 @@
obj-$(CONFIG_EXT4_FS) += ext4.o
ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
- ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
+ ioctl.o namei.o super.o symlink.o hash.o extents.o \
ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
mmp.o indirect.o extents_status.o xattr.o xattr_user.o \
xattr_trusted.o inline.o readpage.o sysfs.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
+ext4-$(CONFIG_EXT4_RESIZE) += resize.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 282a51b..542ebc2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1403,7 +1403,9 @@ struct ext4_sb_info {
struct list_head s_orphan;
struct mutex s_orphan_lock;
unsigned long s_resize_flags; /* Flags indicating if there
- is a resizer */
+ * is a resizer using
+ * EXT4_RESIZING_* bits
+ */
unsigned long s_commit_interval;
u32 s_max_batch_time;
u32 s_min_batch_time;
@@ -2555,14 +2557,6 @@ extern int ext4_generic_delete_entry(handle_t *handle,
int csum_size);
extern bool ext4_empty_dir(struct inode *inode);
-/* resize.c */
-extern int ext4_group_add(struct super_block *sb,
- struct ext4_new_group_data *input);
-extern int ext4_group_extend(struct super_block *sb,
- struct ext4_super_block *es,
- ext4_fsblk_t n_blocks_count);
-extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
-
/* super.c */
extern int ext4_seq_options_show(struct seq_file *seq, void *offset);
extern int ext4_calculate_overhead(struct super_block *sb);
@@ -3239,10 +3233,6 @@ static inline void ext4_inode_resume_unlocked_dio(struct inode *inode)
EXT4_WQ_HASH_SZ])
extern wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
-#define EXT4_RESIZING 0
-extern int ext4_resize_begin(struct super_block *sb);
-extern void ext4_resize_end(struct super_block *sb);
-
static inline void ext4_set_io_unwritten_flag(struct inode *inode,
struct ext4_io_end *io_end)
{
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index bf5ae8e..81d28d2 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -18,6 +18,7 @@
#include <asm/uaccess.h>
#include "ext4_jbd2.h"
#include "ext4.h"
+#include "resize.h"
/**
* Swap memory between @a and @b for @len bytes.
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index cf68100..4c7cd75 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include "ext4_jbd2.h"
+#include "resize.h"
int ext4_resize_begin(struct super_block *sb)
{
@@ -45,7 +46,8 @@ int ext4_resize_begin(struct super_block *sb)
return -EPERM;
}
- if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
+ if (test_and_set_bit_lock(EXT4_RESIZING_ACTIVE,
+ &EXT4_SB(sb)->s_resize_flags))
ret = -EBUSY;
return ret;
@@ -53,7 +55,7 @@ int ext4_resize_begin(struct super_block *sb)
void ext4_resize_end(struct super_block *sb)
{
- clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
+ clear_bit_unlock(EXT4_RESIZING_ACTIVE, &EXT4_SB(sb)->s_resize_flags);
smp_mb__after_atomic();
}
diff --git a/fs/ext4/resize.h b/fs/ext4/resize.h
new file mode 100644
index 0000000..df15285
--- /dev/null
+++ b/fs/ext4/resize.h
@@ -0,0 +1,42 @@
+/*
+ * linux/fs/ext4/resize.h
+ *
+ */
+
+#ifdef CONFIG_EXT4_RESIZE
+#define EXT4_RESIZING_ACTIVE 0
+extern int ext4_resize_begin(struct super_block *sb);
+extern void ext4_resize_end(struct super_block *sb);
+extern int ext4_group_add(struct super_block *sb,
+ struct ext4_new_group_data *input);
+extern int ext4_group_extend(struct super_block *sb,
+ struct ext4_super_block *es, ext4_fsblk_t n_blocks_count);
+extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);
+#else
+static int ext4_resize_begin(struct super_block *sb)
+{
+ return -EOPNOTSUPP;
+}
+
+static void ext4_resize_end(struct super_block *sb)
+{
+}
+
+static inline int ext4_group_add(struct super_block *sb,
+ struct ext4_new_group_data *input)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int ext4_group_extend(struct super_block *sb,
+ struct ext4_super_block *es, ext4_fsblk_t n_blocks_count)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int ext4_resize_fs(struct super_block *sb,
+ ext4_fsblk_t n_blocks_count)
+{
+ return -EOPNOTSUPP;
+}
+#endif
--
2.7.4
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