The patch titled
document i_size_write locking rules
has been added to the -mm tree. Its filename is
document-i_size_write-locking-rules.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: document i_size_write locking rules
From: Miklos Szeredi <miklos@xxxxxxxxxx>
Unless someone reads the documentation for write_seqcount_{begin,end} it is
not obvious, that i_size_write() needs locking. Especially, that lack of such
locking can result in a system hang.
Signed-off-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/fs.h | 6 +++++-
1 files changed, 5 insertions(+), 1 deletion(-)
diff -puN include/linux/fs.h~document-i_size_write-locking-rules include/linux/fs.h
--- a/include/linux/fs.h~document-i_size_write-locking-rules
+++ a/include/linux/fs.h
@@ -656,7 +656,11 @@ static inline loff_t i_size_read(struct
#endif
}
-
+/*
+ * NOTE: unlike i_size_read(), i_size_write() does need locking around it
+ * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
+ * can be lost, resulting in subsequent i_size_read() calls spinning forever.
+ */
static inline void i_size_write(struct inode *inode, loff_t i_size)
{
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
_
Patches currently in -mm which might be from miklos@xxxxxxxxxx are
fuse-fix-hang-on-smp.patch
document-i_size_write-locking-rules.patch
fuse-locking-fix-for-nlookup.patch
fuse-fix-spurious-bug.patch
fuse-fix-handling-of-moved-directory.patch
fuse-fix-dereferencing-dentry-parent.patch
fuse-update-userspace-interface-to-version-78.patch
fuse-minor-cleanup-in-fuse_dentry_revalidate.patch
fuse-add-support-for-block-device-based-filesystems.patch
fuse-add-blksize-option.patch
fuse-add-bmap-support.patch
fuse-add-destroy-operation.patch
-
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