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/inode.c b/fs/nilfs2/inode.c
index 289d179..4bf1e2c 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -77,7 +77,6 @@
goto out;
err = nilfs_bmap_insert(ii->i_bmap, (unsigned long)blkoff,
(unsigned long)bh_result);
- nilfs_transaction_end(inode->i_sb, !err);
if (unlikely(err != 0)) {
if (err == -EEXIST) {
/*
@@ -100,8 +99,10 @@
inode->i_ino);
err = -EIO;
}
+ nilfs_transaction_abort(inode->i_sb);
goto out;
}
+ nilfs_transaction_commit(inode->i_sb); /* never fails */
/* Error handling should be detailed */
set_buffer_new(bh_result);
map_bh(bh_result, inode->i_sb, 0); /* dbn must be changed
@@ -203,7 +204,7 @@
err = block_write_begin(file, mapping, pos, len, flags, pagep,
fsdata, nilfs_get_block);
if (unlikely(err))
- nilfs_transaction_end(inode->i_sb, 0);
+ nilfs_transaction_abort(inode->i_sb);
return err;
}
@@ -221,7 +222,7 @@
copied = generic_write_end(file, mapping, pos, len, copied, page,
fsdata);
nilfs_set_file_dirty(NILFS_SB(inode->i_sb), inode, nr_dirty);
- err = nilfs_transaction_end(inode->i_sb, 1);
+ err = nilfs_transaction_commit(inode->i_sb);
return err ? : copied;
}
@@ -641,7 +642,7 @@
nilfs_set_transaction_flag(NILFS_TI_SYNC);
nilfs_set_file_dirty(NILFS_SB(sb), inode, 0);
- nilfs_transaction_end(sb, 1);
+ nilfs_transaction_commit(sb);
/* May construct a logical segment and may fail in sync mode.
But truncate has no return value. */
}
@@ -669,7 +670,7 @@
/* nilfs_free_inode() marks inode buffer dirty */
if (IS_SYNC(inode))
nilfs_set_transaction_flag(NILFS_TI_SYNC);
- nilfs_transaction_end(sb, 1);
+ nilfs_transaction_commit(sb);
/* May construct a logical segment and may fail in sync mode.
But delete_inode has no return value. */
}
@@ -679,7 +680,7 @@
struct nilfs_transaction_info ti;
struct inode *inode = dentry->d_inode;
struct super_block *sb = inode->i_sb;
- int err, err2;
+ int err;
err = inode_change_ok(inode, iattr);
if (err)
@@ -691,8 +692,12 @@
err = inode_setattr(inode, iattr);
if (!err && (iattr->ia_valid & ATTR_MODE))
err = nilfs_acl_chmod(inode);
- err2 = nilfs_transaction_end(sb, 1);
- return err ? : err2;
+ if (likely(!err))
+ err = nilfs_transaction_commit(sb);
+ else
+ nilfs_transaction_abort(sb);
+
+ return err;
}
int nilfs_load_inode_block(struct nilfs_sb_info *sbi, struct inode *inode,
@@ -817,5 +822,5 @@
nilfs_transaction_begin(inode->i_sb, &ti, 0);
if (likely(inode->i_ino != NILFS_SKETCH_INO))
nilfs_mark_inode_dirty(inode);
- nilfs_transaction_end(inode->i_sb, 1); /* never fails */
+ nilfs_transaction_commit(inode->i_sb); /* never fails */
}
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;
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 6ab8475..e0a632b 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -123,7 +123,10 @@
brelse(bh);
failed_unlock:
- nilfs_transaction_end(sb, !err);
+ if (likely(!err))
+ err = nilfs_transaction_commit(sb);
+ else
+ nilfs_transaction_abort(sb);
if (writer)
nilfs_put_writer(nilfs);
out:
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index 95d1b29..df70dad 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -109,7 +109,7 @@
{
struct inode *inode;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
if (err)
@@ -123,8 +123,12 @@
mark_inode_dirty(inode);
err = nilfs_add_nondir(dentry, inode);
}
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
}
static int
@@ -132,7 +136,7 @@
{
struct inode *inode;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
if (!new_valid_dev(rdev))
return -EINVAL;
@@ -147,8 +151,12 @@
mark_inode_dirty(inode);
err = nilfs_add_nondir(dentry, inode);
}
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
}
static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
@@ -158,7 +166,7 @@
struct super_block *sb = dir->i_sb;
unsigned l = strlen(symname)+1;
struct inode *inode;
- int err, err2;
+ int err;
if (l > sb->s_blocksize)
return -ENAMETOOLONG;
@@ -184,8 +192,12 @@
err = nilfs_add_nondir(dentry, inode);
out:
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
out_fail:
inode_dec_link_count(inode);
@@ -198,7 +210,7 @@
{
struct inode *inode = old_dentry->d_inode;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
if (inode->i_nlink >= NILFS_LINK_MAX)
return -EMLINK;
@@ -212,15 +224,19 @@
atomic_inc(&inode->i_count);
err = nilfs_add_nondir(dentry, inode);
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
}
static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct inode *inode;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
if (dir->i_nlink >= NILFS_LINK_MAX)
return -EMLINK;
@@ -252,8 +268,12 @@
d_instantiate(dentry, inode);
out:
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
out_fail:
inode_dec_link_count(inode);
@@ -270,7 +290,7 @@
struct nilfs_dir_entry *de;
struct page *page;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
if (err)
@@ -300,15 +320,19 @@
inode_dec_link_count(inode);
err = 0;
out:
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
}
static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
struct nilfs_transaction_info ti;
- int err, err2;
+ int err;
err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
if (err)
@@ -323,8 +347,12 @@
inode_dec_link_count(dir);
}
}
- err2 = nilfs_transaction_end(dir->i_sb, !err);
- return err ? : err2;
+ if (!err)
+ err = nilfs_transaction_commit(dir->i_sb);
+ else
+ nilfs_transaction_abort(dir->i_sb);
+
+ return err;
}
static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -404,7 +432,7 @@
inode_dec_link_count(old_dir);
}
- err = nilfs_transaction_end(old_dir->i_sb, 1);
+ err = nilfs_transaction_commit(old_dir->i_sb);
return err;
out_dir:
@@ -416,7 +444,7 @@
kunmap(old_page);
page_cache_release(old_page);
out:
- nilfs_transaction_end(old_dir->i_sb, 0);
+ nilfs_transaction_abort(old_dir->i_sb);
return err;
}
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index 17458ad..48c0706 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -166,7 +166,8 @@
int nilfs_transaction_begin(struct super_block *,
struct nilfs_transaction_info *, int);
-int nilfs_transaction_end(struct super_block *, int);
+int nilfs_transaction_commit(struct super_block *);
+void nilfs_transaction_abort(struct super_block *);
static inline void nilfs_set_transaction_flag(unsigned int flag)
{
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index ad65a73..6d66c5c 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -163,8 +163,8 @@
else {
/*
* If journal_info field is occupied by other FS,
- * we save it and restore on nilfs_transaction_end().
- * But this should never happen.
+ * it is saved and will be restored on
+ * nilfs_transaction_commit().
*/
printk(KERN_WARNING
"NILFS warning: journal info from a different "
@@ -195,7 +195,7 @@
*
* nilfs_transaction_begin() acquires a reader/writer semaphore, called
* the segment semaphore, to make a segment construction and write tasks
- * exclusive. The function is used with nilfs_transaction_end() in pairs.
+ * exclusive. The function is used with nilfs_transaction_commit() in pairs.
* The region enclosed by these two functions can be nested. To avoid a
* deadlock, the semaphore is only acquired or released in the outermost call.
*
@@ -212,8 +212,6 @@
*
* %-ENOMEM - Insufficient memory available.
*
- * %-ERESTARTSYS - Interrupted
- *
* %-ENOSPC - No space left on device
*/
int nilfs_transaction_begin(struct super_block *sb,
@@ -248,16 +246,17 @@
}
/**
- * nilfs_transaction_end - end indivisible file operations.
+ * nilfs_transaction_commit - commit indivisible file operations.
* @sb: super block
- * @commit: commit flag (0 for no change)
*
- * nilfs_transaction_end() releases the read semaphore which is
- * acquired by nilfs_transaction_begin(). Its releasing is only done
- * in outermost call of this function. If the nilfs_transaction_info
- * was allocated dynamically, it is given back to a slab cache.
+ * nilfs_transaction_commit() releases the read semaphore which is
+ * acquired by nilfs_transaction_begin(). This is only performed
+ * in outermost call of this function. If a commit flag is set,
+ * nilfs_transaction_commit() sets a timer to start the segment
+ * constructor. If a sync flag is set, it starts construction
+ * directly.
*/
-int nilfs_transaction_end(struct super_block *sb, int commit)
+int nilfs_transaction_commit(struct super_block *sb)
{
struct nilfs_transaction_info *ti = current->journal_info;
struct nilfs_sb_info *sbi;
@@ -265,9 +264,7 @@
int err = 0;
BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
-
- if (commit)
- ti->ti_flags |= NILFS_TI_COMMIT;
+ ti->ti_flags |= NILFS_TI_COMMIT;
if (ti->ti_count > 0) {
ti->ti_count--;
return 0;
@@ -291,6 +288,22 @@
return err;
}
+void nilfs_transaction_abort(struct super_block *sb)
+{
+ struct nilfs_transaction_info *ti = current->journal_info;
+
+ BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
+ if (ti->ti_count > 0) {
+ ti->ti_count--;
+ return;
+ }
+ up_read(&NILFS_SB(sb)->s_nilfs->ns_segctor_sem);
+
+ current->journal_info = ti->ti_save;
+ if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
+ kmem_cache_free(nilfs_transaction_cachep, ti);
+}
+
void nilfs_relax_pressure_in_lock(struct super_block *sb)
{
struct nilfs_sb_info *sbi = NILFS_SB(sb);
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index dee8d83..9cd3c11 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -112,8 +112,8 @@
/*
* Following fields are dedicated to a writable FS-instance.
* Except for the period seeking checkpoint, code outside the segment
- * constructor must lock a segment semaphore with transaction_begin()
- * and transaction_end(), when accessing these fields.
+ * constructor must lock a segment semaphore while accessing these
+ * fields.
* The writable FS-instance is sole during a lifetime of the_nilfs.
*/
u64 ns_seg_seq;