Convenience wrapper for sb_write_started(file_inode(inode)->i_sb)), which
has a single occurrence in the code right now.
Document the false negatives of those helpers, which makes them unusable
to assert that sb_start_write() is not held.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/read_write.c | 2 +-
include/linux/fs.h | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 8d381929701c..87e1256d0a67 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1437,7 +1437,7 @@ ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
- lockdep_assert(sb_write_started(file_inode(file_out)->i_sb));
+ lockdep_assert(file_write_started(file_out));
return do_splice_direct(file_in, &pos_in, file_out, &pos_out,
len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e8aa48797bf4..05780d993c7d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1658,11 +1658,32 @@ static inline int __sb_write_started(const struct super_block *sb, int level)
return lockdep_is_held_type(sb->s_writers.rw_sem + level - 1, 1);
}
+/**
+ * sb_write_started - check if SB_FREEZE_WRITE is held
+ * @sb: the super we write to
+ *
+ * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
+ */
static inline bool sb_write_started(const struct super_block *sb)
{
return __sb_write_started(sb, SB_FREEZE_WRITE);
}
+/**
+ * file_write_started - check if SB_FREEZE_WRITE is held
+ * @file: the file we write to
+ *
+ * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN.
+ * May be false positive with !S_ISREG, because file_start_write() has
+ * no effect on !S_ISREG.
+ */
+static inline bool file_write_started(const struct file *file)
+{
+ if (!S_ISREG(file_inode(file)->i_mode))
+ return true;
+ return sb_write_started(file_inode(file)->i_sb);
+}
+
/**
* sb_end_write - drop write access to a superblock
* @sb: the super we wrote to
--
2.34.1
