nilfs2: avoid double error caused by nilfs_transaction_end
Pekka Enberg pointed out that double error handlings found after
nilfs_transaction_end() can be avoided by separating abort operation:
OK, I don't understand this. The only way nilfs_transaction_end() can
fail is if we have NILFS_TI_SYNC set and we fail to construct the
segment. But why do we want to construct a segment if we don't commit?
I guess what I'm asking is why don't we have a separate
nilfs_transaction_abort() function that can't fail for the erroneous
case to avoid this double error value tracking thing?
This does the separation and renames nilfs_transaction_end() to
nilfs_transaction_commit() for clarification.
Since, some calls of these functions were used just for exclusion control
against the segment constructor, they are replaced with semaphore
operations.
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 02e91e1..5ce06a0 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -105,7 +105,11 @@
nilfs_transaction_begin(inode->i_sb, &ti, 0);
ret = nilfs_cpfile_change_cpmode(
cpfile, cpmode.cm_cno, cpmode.cm_mode);
- nilfs_transaction_end(inode->i_sb, !ret);
+ if (unlikely(ret < 0)) {
+ nilfs_transaction_abort(inode->i_sb);
+ return ret;
+ }
+ nilfs_transaction_commit(inode->i_sb); /* never fails */
return ret;
}
@@ -125,7 +129,11 @@
nilfs_transaction_begin(inode->i_sb, &ti, 0);
ret = nilfs_cpfile_delete_checkpoint(cpfile, cno);
- nilfs_transaction_end(inode->i_sb, !ret);
+ if (unlikely(ret < 0)) {
+ nilfs_transaction_abort(inode->i_sb);
+ return ret;
+ }
+ nilfs_transaction_commit(inode->i_sb); /* never fails */
return ret;
}
@@ -142,16 +150,17 @@
{
struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_argv argv;
- struct nilfs_transaction_info ti;
int ret;
if (copy_from_user(&argv, argp, sizeof(argv)))
return -EFAULT;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
+ down_read(&nilfs->ns_segctor_sem);
ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
nilfs_ioctl_do_get_cpinfo);
- nilfs_transaction_end(inode->i_sb, 0);
+ up_read(&nilfs->ns_segctor_sem);
+ if (ret < 0)
+ return ret;
if (copy_to_user(argp, &argv, sizeof(argv)))
ret = -EFAULT;
@@ -161,14 +170,13 @@
static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
- struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
+ struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_cpstat cpstat;
- struct nilfs_transaction_info ti;
int ret;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
- ret = nilfs_cpfile_get_stat(cpfile, &cpstat);
- nilfs_transaction_end(inode->i_sb, 0);
+ down_read(&nilfs->ns_segctor_sem);
+ ret = nilfs_cpfile_get_stat(nilfs->ns_cpfile, &cpstat);
+ up_read(&nilfs->ns_segctor_sem);
if (ret < 0)
return ret;
@@ -189,16 +197,17 @@
{
struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_argv argv;
- struct nilfs_transaction_info ti;
int ret;
if (copy_from_user(&argv, argp, sizeof(argv)))
return -EFAULT;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
+ down_read(&nilfs->ns_segctor_sem);
ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
nilfs_ioctl_do_get_suinfo);
- nilfs_transaction_end(inode->i_sb, 0);
+ up_read(&nilfs->ns_segctor_sem);
+ if (ret < 0)
+ return ret;
if (copy_to_user(argp, &argv, sizeof(argv)))
ret = -EFAULT;
@@ -208,14 +217,13 @@
static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
unsigned int cmd, void __user *argp)
{
- struct inode *sufile = NILFS_SB(inode->i_sb)->s_nilfs->ns_sufile;
+ struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_sustat sustat;
- struct nilfs_transaction_info ti;
int ret;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
- ret = nilfs_sufile_get_stat(sufile, &sustat);
- nilfs_transaction_end(inode->i_sb, 0);
+ down_read(&nilfs->ns_segctor_sem);
+ ret = nilfs_sufile_get_stat(nilfs->ns_sufile, &sustat);
+ up_read(&nilfs->ns_segctor_sem);
if (ret < 0)
return ret;
@@ -236,16 +244,17 @@
{
struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_argv argv;
- struct nilfs_transaction_info ti;
int ret;
if (copy_from_user(&argv, argp, sizeof(argv)))
return -EFAULT;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
+ down_read(&nilfs->ns_segctor_sem);
ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
nilfs_ioctl_do_get_vinfo);
- nilfs_transaction_end(inode->i_sb, 0);
+ up_read(&nilfs->ns_segctor_sem);
+ if (ret < 0)
+ return ret;
if (copy_to_user(argp, &argv, sizeof(argv)))
ret = -EFAULT;
@@ -280,16 +289,17 @@
{
struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
struct nilfs_argv argv;
- struct nilfs_transaction_info ti;
int ret;
if (copy_from_user(&argv, argp, sizeof(argv)))
return -EFAULT;
- nilfs_transaction_begin(inode->i_sb, &ti, 0);
+ down_read(&nilfs->ns_segctor_sem);
ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd),
nilfs_ioctl_do_get_bdescs);
- nilfs_transaction_end(inode->i_sb, 0);
+ up_read(&nilfs->ns_segctor_sem);
+ if (ret < 0)
+ return ret;
if (copy_to_user(argp, &argv, sizeof(argv)))
ret = -EFAULT;