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authorThomas Gleixner <tglx@linutronix.de>2012-03-01 16:12:47 +0100
committerClark Williams <williams@redhat.com>2012-03-14 10:50:15 -0500
commit1361c31f664f187e753fed97dbcd4493f2c67387 (patch)
tree535b3eb9292cd1016864dd0e4b45d91349962125
parent18683e1a3c2451f53659ee2ea032b621f5ed0d8e (diff)
fs: Protect open coded isize seqcount
A writer might be preempted in the write side critical section on RT. Disable preemption to avoid endless spinning of a preempting reader. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
-rw-r--r--include/linux/fs.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 99fb59ceba3b..415fb15f1698 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -903,9 +903,11 @@ static inline loff_t i_size_read(const struct inode *inode)
static inline void i_size_write(struct inode *inode, loff_t i_size)
{
#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+ preempt_disable_rt();
write_seqcount_begin(&inode->i_size_seqcount);
inode->i_size = i_size;
write_seqcount_end(&inode->i_size_seqcount);
+ preempt_enable_rt();
#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
preempt_disable();
inode->i_size = i_size;