fs/direct-io.c: keep dio_warn_stale_pagecache() when CONFIG_BLOCK=n

This helper prints warning if direct I/O write failed to invalidate cache,
and set EIO at inode to warn usersapce about possible data corruption.

See also commit 5a9d929d6e13 ("iomap: report collisions between directio
and buffered writes to userspace").

Direct I/O is supported by non-disk filesystems, for example NFS.  Thus
generic code needs this even in kernel without CONFIG_BLOCK.

Link: http://lkml.kernel.org/r/157270038074.4812.7980855544557488880.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 9329ced..0ec4f27 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -221,27 +221,6 @@ static inline struct page *dio_get_page(struct dio *dio,
 }
 
 /*
- * Warn about a page cache invalidation failure during a direct io write.
- */
-void dio_warn_stale_pagecache(struct file *filp)
-{
-       static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
-       char pathname[128];
-       struct inode *inode = file_inode(filp);
-       char *path;
-
-       errseq_set(&inode->i_mapping->wb_err, -EIO);
-       if (__ratelimit(&_rs)) {
-               path = file_path(filp, pathname, sizeof(pathname));
-               if (IS_ERR(path))
-                       path = "(unknown)";
-               pr_crit("Page cache invalidation failure on direct I/O.  Possible data corruption due to collision with buffered I/O!\n");
-               pr_crit("File: %s PID: %d Comm: %.20s\n", path, current->pid,
-                       current->comm);
-       }
-}
-
-/*
  * dio_complete() - called when all DIO BIO I/O has been completed
  *
  * This drops i_dio_count, lets interested parties know that a DIO operation

diff --git a/include/linux/fs.h b/include/linux/fs.h
index ae6c5c3..eeed80f 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3149,7 +3149,6 @@ enum {
 };
 
 void dio_end_io(struct bio *bio);
-void dio_warn_stale_pagecache(struct file *filp);
 
 ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
                             struct block_device *bdev, struct iov_iter *iter,
@@ -3194,6 +3193,11 @@ static inline void inode_dio_end(struct inode *inode)
                wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
 }
 
+/*
+ * Warn about a page cache invalidation failure diring a direct I/O write.
+ */
+void dio_warn_stale_pagecache(struct file *filp);
+
 extern void inode_set_flags(struct inode *inode, unsigned int flags,
                            unsigned int mask);
 

diff --git a/mm/filemap.c b/mm/filemap.c
index 288e381..189b8f3 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3161,6 +3161,27 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
 }
 EXPORT_SYMBOL(pagecache_write_end);
 
+/*
+ * Warn about a page cache invalidation failure during a direct I/O write.
+ */
+void dio_warn_stale_pagecache(struct file *filp)
+{
+       static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
+       char pathname[128];
+       struct inode *inode = file_inode(filp);
+       char *path;
+
+       errseq_set(&inode->i_mapping->wb_err, -EIO);
+       if (__ratelimit(&_rs)) {
+               path = file_path(filp, pathname, sizeof(pathname));
+               if (IS_ERR(path))
+                       path = "(unknown)";
+               pr_crit("Page cache invalidation failure on direct I/O.  Possible data corruption due to collision with buffered I/O!\n");
+               pr_crit("File: %s PID: %d Comm: %.20s\n", path, current->pid,
+                       current->comm);
+       }
+}
+
 ssize_t
 generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
 {