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Subject[PATCH 4.14 13/71] orangefs: fix deadlock; do not write i_size in read_iter
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Brandenburg <martin@omnibond.com>

commit 6793f1c450b1533a5e9c2493490de771d38b24f9 upstream.

After do_readv_writev, the inode cache is invalidated anyway, so i_size
will never be read. It will be fetched from the server which will also
know about updates from other machines.

Fixes deadlock on 32-bit SMP.

See https://marc.info/?l=linux-fsdevel&m=151268557427760&w=2

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/orangefs/file.c | 7 ++-----
fs/orangefs/orangefs-kernel.h | 11 -----------
2 files changed, 2 insertions(+), 16 deletions(-)

--- a/fs/orangefs/file.c
+++ b/fs/orangefs/file.c
@@ -446,7 +446,7 @@ ssize_t orangefs_inode_read(struct inode
static ssize_t orangefs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
- loff_t pos = *(&iocb->ki_pos);
+ loff_t pos = iocb->ki_pos;
ssize_t rc = 0;

BUG_ON(iocb->private);
@@ -486,9 +486,6 @@ static ssize_t orangefs_file_write_iter(
}
}

- if (file->f_pos > i_size_read(file->f_mapping->host))
- orangefs_i_size_write(file->f_mapping->host, file->f_pos);
-
rc = generic_write_checks(iocb, iter);

if (rc <= 0) {
@@ -502,7 +499,7 @@ static ssize_t orangefs_file_write_iter(
* pos to the end of the file, so we will wait till now to set
* pos...
*/
- pos = *(&iocb->ki_pos);
+ pos = iocb->ki_pos;

rc = do_readv_writev(ORANGEFS_IO_WRITE,
file,
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -566,17 +566,6 @@ do { \
sys_attr.mask = ORANGEFS_ATTR_SYS_ALL_SETABLE; \
} while (0)

-static inline void orangefs_i_size_write(struct inode *inode, loff_t i_size)
-{
-#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
- inode_lock(inode);
-#endif
- i_size_write(inode, i_size);
-#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
- inode_unlock(inode);
-#endif
-}
-
static inline void orangefs_set_timeout(struct dentry *dentry)
{
unsigned long time = jiffies + orangefs_dcache_timeout_msecs*HZ/1000;

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