diff options
Diffstat (limited to 'debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch')
| -rw-r--r-- | debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch | 45 |
1 files changed, 7 insertions, 38 deletions
diff --git a/debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch b/debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch index 1201ce1f7..67f0727af 100644 --- a/debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch +++ b/debian/patches-rt/fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch @@ -1,7 +1,7 @@ From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Fri, 20 Oct 2017 11:29:53 +0200 Subject: [PATCH] fs/dcache: disable preemption on i_dir_seq's write side -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.2/older/patches-5.2.17-rt9.tar.xz +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz i_dir_seq is an opencoded seqcounter. Based on the code it looks like we could have two writers in parallel despite the fact that the d_lock is @@ -18,13 +18,12 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- fs/dcache.c | 12 +++++++----- fs/inode.c | 2 +- - fs/libfs.c | 6 ++++-- include/linux/fs.h | 2 +- - 4 files changed, 13 insertions(+), 9 deletions(-) + 3 files changed, 9 insertions(+), 7 deletions(-) --- a/fs/dcache.c +++ b/fs/dcache.c -@@ -2418,9 +2418,10 @@ EXPORT_SYMBOL(d_rehash); +@@ -2482,9 +2482,10 @@ EXPORT_SYMBOL(d_rehash); static inline unsigned start_dir_add(struct inode *dir) { @@ -37,7 +36,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> return n; cpu_relax(); } -@@ -2428,7 +2429,8 @@ static inline unsigned start_dir_add(str +@@ -2492,7 +2493,8 @@ static inline unsigned start_dir_add(str static inline void end_dir_add(struct inode *dir, unsigned n) { @@ -47,7 +46,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> } static void d_wait_lookup(struct dentry *dentry) -@@ -2461,7 +2463,7 @@ struct dentry *d_alloc_parallel(struct d +@@ -2525,7 +2527,7 @@ struct dentry *d_alloc_parallel(struct d retry: rcu_read_lock(); @@ -56,7 +55,7 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> r_seq = read_seqbegin(&rename_lock); dentry = __d_lookup_rcu(parent, name, &d_seq); if (unlikely(dentry)) { -@@ -2489,7 +2491,7 @@ struct dentry *d_alloc_parallel(struct d +@@ -2553,7 +2555,7 @@ struct dentry *d_alloc_parallel(struct d } hlist_bl_lock(b); @@ -76,39 +75,9 @@ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> inode->i_rdev = 0; inode->dirtied_when = 0; ---- a/fs/libfs.c -+++ b/fs/libfs.c -@@ -91,7 +91,7 @@ static struct dentry *next_positive(stru - struct list_head *from, - int count) - { -- unsigned *seq = &parent->d_inode->i_dir_seq, n; -+ unsigned *seq = &parent->d_inode->__i_dir_seq, n; - struct dentry *res; - struct list_head *p; - bool skipped; -@@ -124,8 +124,9 @@ static struct dentry *next_positive(stru - static void move_cursor(struct dentry *cursor, struct list_head *after) - { - struct dentry *parent = cursor->d_parent; -- unsigned n, *seq = &parent->d_inode->i_dir_seq; -+ unsigned n, *seq = &parent->d_inode->__i_dir_seq; - spin_lock(&parent->d_lock); -+ preempt_disable_rt(); - for (;;) { - n = *seq; - if (!(n & 1) && cmpxchg(seq, n, n + 1) == n) -@@ -138,6 +139,7 @@ static void move_cursor(struct dentry *c - else - list_add_tail(&cursor->d_child, &parent->d_subdirs); - smp_store_release(seq, n + 2); -+ preempt_enable_rt(); - spin_unlock(&parent->d_lock); - } - --- a/include/linux/fs.h +++ b/include/linux/fs.h -@@ -709,7 +709,7 @@ struct inode { +@@ -716,7 +716,7 @@ struct inode { struct block_device *i_bdev; struct cdev *i_cdev; char *i_link; |