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authorAl Viro <viro@zeniv.linux.org.uk>2014-08-07 07:32:06 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2014-08-07 14:40:08 -0400
commit0aec09d049d7e994eba54bad4376dd8f58eab797 (patch)
tree220068a33da8eadd95e3006f626f3d80b8822f6b
parent2798d4ce61601808b965253d60624bbf201b51b0 (diff)
downloadop-kernel-dev-0aec09d049d7e994eba54bad4376dd8f58eab797.zip
op-kernel-dev-0aec09d049d7e994eba54bad4376dd8f58eab797.tar.gz
drop ->s_umount around acct_auto_close()
just repeat the frozen check after regaining it, and check that sb is still alive. If several threads hit acct_auto_close() at the same time, acct_auto_close() will survive that just fine. And we really don't want to play with writes and closing the file with ->s_umount held exclusive - it's a deadlock country. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/super.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/fs/super.c b/fs/super.c
index 52ed93e..a369f89 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -702,12 +702,22 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
return -EACCES;
#endif
- if (flags & MS_RDONLY)
- acct_auto_close(&sb->s_pins);
- shrink_dcache_sb(sb);
-
remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
+ if (remount_ro) {
+ if (sb->s_pins.first) {
+ up_write(&sb->s_umount);
+ acct_auto_close(&sb->s_pins);
+ down_write(&sb->s_umount);
+ if (!sb->s_root)
+ return 0;
+ if (sb->s_writers.frozen != SB_UNFROZEN)
+ return -EBUSY;
+ remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
+ }
+ }
+ shrink_dcache_sb(sb);
+
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if (remount_ro) {
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