When user asks for O_NONBLOCK behavior for a file descriptor, return
EAGAIN instead of blocking on a frozen filesystem.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/btrfs/file.c | 3 ++-
fs/cifs/file.c | 3 ++-
fs/fuse/file.c | 3 ++-
fs/ntfs/file.c | 3 ++-
fs/ocfs2/file.c | 3 ++-
fs/xfs/xfs_file.c | 3 ++-
include/linux/fs.h | 10 ++++++++++
mm/filemap.c | 3 ++-
8 files changed, 24 insertions(+), 7 deletions(-)
This is a second version of patches to fix BSD process accounting deadlocks
on frozen filesystem. This time I used O_NONBLOCK to indicate write shouldn't
block on frozen filesystem as Dave Chinner suggested.
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9ab1bed..6eb2e30 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1411,7 +1411,8 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
ssize_t err = 0;
size_t count, ocount;
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
mutex_lock(&inode->i_mutex);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index edb25b4..1629e47 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2448,7 +2448,8 @@ cifs_writev(struct kiocb *iocb, const struct iovec *iov,
BUG_ON(iocb->ki_pos != pos);
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
/*
* We need to hold the sem to be sure nobody modifies lock list
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 78d2837..641df9e 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -947,7 +947,8 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
return err;
count = ocount;
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
mutex_lock(&inode->i_mutex);
/* We can write back this queue in page reclaim */
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 1ecf464..028b349 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -2118,7 +2118,8 @@ static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
BUG_ON(iocb->ki_pos != pos);
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
mutex_lock(&inode->i_mutex);
ret = ntfs_file_aio_write_nolock(iocb, iov, nr_segs, &iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 5a4ee77..93ef34d 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2265,7 +2265,8 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
if (iocb->ki_left == 0)
return 0;
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
appending = file->f_flags & O_APPEND ? 1 : 0;
direct_io = file->f_flags & O_DIRECT ? 1 : 0;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index aa473fa..7d8af61 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -771,7 +771,8 @@ xfs_file_aio_write(
if (ocount == 0)
return 0;
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
ret = -EIO;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b33cfc9..2325e95 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1401,6 +1401,16 @@ static inline int sb_start_write_trylock(struct super_block *sb)
return __sb_start_write(sb, SB_FREEZE_WRITE, false);
}
+/*
+ * sb_start_write() for writing into a file. When file has O_NONBLOCK set,
+ * we use trylock semantics, otherwise we block on frozen filesystem.
+ */
+static inline int sb_start_file_write(struct file *file)
+{
+ return __sb_start_write(file->f_mapping->host->i_sb, SB_FREEZE_WRITE,
+ !(file->f_flags & O_NONBLOCK));
+}
+
/**
* sb_start_pagefault - get write access to a superblock from a page fault
* @sb: the super we write to
diff --git a/mm/filemap.c b/mm/filemap.c
index 83efee7..3b2812b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2527,7 +2527,8 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
BUG_ON(iocb->ki_pos != pos);
- sb_start_write(inode->i_sb);
+ if (!sb_start_file_write(file))
+ return -EAGAIN;
mutex_lock(&inode->i_mutex);
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
--
1.7.1
--
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