The patch titled
Allow SysRq emergency thaw to thaw frozen filesystems (v99)
has been added to the -mm tree. Its filename is
filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99.patch
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Subject: Allow SysRq emergency thaw to thaw frozen filesystems (v99)
From: Eric Sandeen <sandeen@xxxxxxxxxx>
(this version fixes a couple small issues raised by Randy Dunlap)
(and adds sb_lock locking I forgot, as akpm pointed out)
(and includes Randy's CONFIG_BLOCK fix)
(and does proper locking, finally)
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Cc: Takashi Sato <t-sato@xxxxxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/sysrq.txt | 2 +-
fs/buffer.c | 10 ++++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff -puN Documentation/sysrq.txt~filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99 Documentation/sysrq.txt
--- a/Documentation/sysrq.txt~filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99
+++ a/Documentation/sysrq.txt
@@ -81,7 +81,7 @@ On all - write a character to /proc/sys
'i' - Send a SIGKILL to all processes, except for init.
-'j' - Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl.
+'j' - Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl.
'k' - Secure Access Key (SAK) Kills all programs on the current virtual
console. NOTE: See important comments below in SAK section.
diff -puN fs/buffer.c~filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99 fs/buffer.c
--- a/fs/buffer.c~filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99
+++ a/fs/buffer.c
@@ -263,11 +263,21 @@ void do_thaw_all(unsigned long unused)
struct super_block *sb;
char b[BDEVNAME_SIZE];
+ spin_lock(&sb_lock);
+restart:
list_for_each_entry(sb, &super_blocks, s_list) {
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&sb->s_umount);
while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
printk(KERN_WARNING "Emergency Thaw on %s\n",
bdevname(sb->s_bdev, b));
+ up_read(&sb->s_umount);
+ spin_lock(&sb_lock);
+ if (__put_super_and_need_restart(sb))
+ goto restart;
}
+ spin_unlock(&sb_lock);
printk(KERN_WARNING "Emergency Thaw complete\n");
}
_
Patches currently in -mm which might be from sandeen@xxxxxxxxxx are
origin.patch
linux-next.patch
filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems.patch
filesystem-freeze-allow-sysrq-emergency-thaw-to-thaw-frozen-filesystems-99.patch
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