Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull second round of VFS updates from Al Viro:
 "Assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xtensa simdisk: fix braino in "xtensa simdisk: switch to proc_create_data()"
  hostfs: use kmalloc instead of kzalloc
  hostfs: move HOSTFS_SUPER_MAGIC to <linux/magic.h>
  hostfs: remove "will unlock" comment
  vfs: use list_move instead of list_del/list_add
  proc_devtree: Replace include linux/module.h with linux/export.h
  create_mnt_ns: unidiomatic use of list_add()
  fs: remove dentry_lru_prune()
  Removed unused typedef to avoid "unused local typedef" warnings.
  kill fs/read_write.h
  fs: Fix hang with BSD accounting on frozen filesystem
  sun3_scsi: add ->show_info()
  nubus: Kill nubus_proc_detach_device()
  more mode_t whack-a-mole...
  do_coredump(): don't wait for thaw if coredump has already been interrupted
  do_mount(): fix a leak introduced in 3.9 ("mount: consolidate permission checks")

19 files changed, 123 insertions, 175 deletions

diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c
index 4a06d70ddf5e..88608cc11b8c 100644
--- a/arch/xtensa/platforms/iss/simdisk.c
+++ b/arch/xtensa/platforms/iss/simdisk.c
@@ -231,7 +231,7 @@ static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
 }
 
 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
-			size_t size, loff_t *ppos)
+			size_t count, loff_t *ppos)
 {
 	char *tmp = kmalloc(count + 1, GFP_KERNEL);
 	struct simdisk *dev = PDE_DATA(file_inode(file));
diff --git a/drivers/hwmon/abx500.c b/drivers/hwmon/abx500.c
index b4ad87b31a37..eee1134274c8 100644
--- a/drivers/hwmon/abx500.c
+++ b/drivers/hwmon/abx500.c
@@ -260,7 +260,7 @@ static ssize_t show_max_alarm(struct device *dev,
 	return sprintf(buf, "%d\n", data->max_alarm[attr->index]);
 }
 
-static mode_t abx500_attrs_visible(struct kobject *kobj,
+static umode_t abx500_attrs_visible(struct kobject *kobj,
 				   struct attribute *attr, int n)
 {
 	struct device *dev = container_of(kobj, struct device, kobj);
diff --git a/drivers/nubus/proc.c b/drivers/nubus/proc.c
index b8286ed65919..5371b374f1fe 100644
--- a/drivers/nubus/proc.c
+++ b/drivers/nubus/proc.c
@@ -147,21 +147,6 @@ int nubus_proc_attach_device(struct nubus_dev *dev)
 }
 EXPORT_SYMBOL(nubus_proc_attach_device);
 
-/* FIXME: this is certainly broken! */
-int nubus_proc_detach_device(struct nubus_dev *dev)
-{
-	struct proc_dir_entry *e;
-
-	if ((e = dev->procdir)) {
-		if (atomic_read(&e->count))
-			return -EBUSY;
-		remove_proc_entry(e->name, proc_bus_nubus_dir);
-		dev->procdir = NULL;
-	}
-	return 0;
-}
-EXPORT_SYMBOL(nubus_proc_detach_device);
-
 /*
  * /proc/nubus stuff
  */
diff --git a/drivers/scsi/sun3_NCR5380.c b/drivers/scsi/sun3_NCR5380.c
index 7e12a2e4e0a3..636bbe0ea84c 100644
--- a/drivers/scsi/sun3_NCR5380.c
+++ b/drivers/scsi/sun3_NCR5380.c
@@ -661,121 +661,94 @@ static void __init NCR5380_print_options (struct Scsi_Host *instance)
  * Inputs : instance, pointer to this instance.  
  */
 
-static void NCR5380_print_status (struct Scsi_Host *instance)
+static void lprint_Scsi_Cmnd(Scsi_Cmnd *cmd)
 {
-    char *pr_bfr;
-    char *start;
-    int len;
-
-    NCR_PRINT(NDEBUG_ANY);
-    NCR_PRINT_PHASE(NDEBUG_ANY);
-
-    pr_bfr = (char *) __get_free_page(GFP_ATOMIC);
-    if (!pr_bfr) {
-	printk("NCR5380_print_status: no memory for print buffer\n");
-	return;
-    }
-    len = NCR5380_proc_info(instance, pr_bfr, &start, 0, PAGE_SIZE, 0);
-    pr_bfr[len] = 0;
-    printk("\n%s\n", pr_bfr);
-    free_page((unsigned long) pr_bfr);
+	int i, s;
+	unsigned char *command;
+	printk("scsi%d: destination target %d, lun %d\n",
+		H_NO(cmd), cmd->device->id, cmd->device->lun);
+	printk(KERN_CONT "        command = ");
+	command = cmd->cmnd;
+	printk(KERN_CONT "%2d (0x%02x)", command[0], command[0]);
+	for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
+		printk(KERN_CONT " %02x", command[i]);
+	printk("\n");
 }
 
-
-/******************************************/
-/*
- * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
- *
- * *buffer: I/O buffer
- * **start: if inout == FALSE pointer into buffer where user read should start
- * offset: current offset
- * length: length of buffer
- * hostno: Scsi_Host host_no
- * inout: TRUE - user is writing; FALSE - user is reading
- *
- * Return the number of bytes read from or written
-*/
-
-#undef SPRINTF
-#define SPRINTF(fmt,args...) \
-  do { if (pos + strlen(fmt) + 20 /* slop */ < buffer + length) \
-	 pos += sprintf(pos, fmt , ## args); } while(0)
-static
-char *lprint_Scsi_Cmnd(struct scsi_cmnd *cmd, char *pos, char *buffer,
-		       int length);
-
-static int NCR5380_proc_info(struct Scsi_Host *instance, char *buffer,
-			     char **start, off_t offset, int length, int inout)
+static void NCR5380_print_status(struct Scsi_Host *instance)
 {
-    char *pos = buffer;
-    struct NCR5380_hostdata *hostdata;
-    struct scsi_cmnd *ptr;
-    unsigned long flags;
-    off_t begin = 0;
-#define check_offset()				\
-    do {					\
-	if (pos - buffer < offset - begin) {	\
-	    begin += pos - buffer;		\
-	    pos = buffer;			\
-	}					\
-    } while (0)
-
-    hostdata = (struct NCR5380_hostdata *)instance->hostdata;
-
-    if (inout) { /* Has data been written to the file ? */
-	return(-ENOSYS);  /* Currently this is a no-op */
-    }
-    SPRINTF("NCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE);
-    check_offset();
-    local_irq_save(flags);
-    SPRINTF("NCR5380: coroutine is%s running.\n", main_running ? "" : "n't");
-    check_offset();
-    if (!hostdata->connected)
-	SPRINTF("scsi%d: no currently connected command\n", HOSTNO);
-    else
-	pos = lprint_Scsi_Cmnd ((struct scsi_cmnd *) hostdata->connected,
-				pos, buffer, length);
-    SPRINTF("scsi%d: issue_queue\n", HOSTNO);
-    check_offset();
-    for (ptr = (struct scsi_cmnd *) hostdata->issue_queue; ptr; ptr = NEXT(ptr))
-    {
-	pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length);
-	check_offset();
-    }
-
-    SPRINTF("scsi%d: disconnected_queue\n", HOSTNO);
-    check_offset();
-    for (ptr = (struct scsi_cmnd *) hostdata->disconnected_queue; ptr;
-	 ptr = NEXT(ptr)) {
-	pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length);
-	check_offset();
-    }
+	struct NCR5380_hostdata *hostdata;
+	Scsi_Cmnd *ptr;
+	unsigned long flags;
+
+	NCR_PRINT(NDEBUG_ANY);
+	NCR_PRINT_PHASE(NDEBUG_ANY);
+
+	hostdata = (struct NCR5380_hostdata *)instance->hostdata;
+
+	printk("\nNCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE);
+	local_irq_save(flags);
+	printk("NCR5380: coroutine is%s running.\n",
+		main_running ? "" : "n't");
+	if (!hostdata->connected)
+		printk("scsi%d: no currently connected command\n", HOSTNO);
+	else
+		lprint_Scsi_Cmnd((Scsi_Cmnd *) hostdata->connected);
+	printk("scsi%d: issue_queue\n", HOSTNO);
+	for (ptr = (Scsi_Cmnd *)hostdata->issue_queue; ptr; ptr = NEXT(ptr))
+		lprint_Scsi_Cmnd(ptr);
+
+	printk("scsi%d: disconnected_queue\n", HOSTNO);
+	for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
+	     ptr = NEXT(ptr))
+		lprint_Scsi_Cmnd(ptr);
 
-    local_irq_restore(flags);
-    *start = buffer + (offset - begin);
-    if (pos - buffer < offset - begin)
-	return 0;
-    else if (pos - buffer - (offset - begin) < length)
-	return pos - buffer - (offset - begin);
-    return length;
+	local_irq_restore(flags);
+	printk("\n");
 }
 
-static char *lprint_Scsi_Cmnd(struct scsi_cmnd *cmd, char *pos, char *buffer,
-			      int length)
+static void show_Scsi_Cmnd(Scsi_Cmnd *cmd, struct seq_file *m)
 {
-    int i, s;
-    unsigned char *command;
-    SPRINTF("scsi%d: destination target %d, lun %d\n",
-	    H_NO(cmd), cmd->device->id, cmd->device->lun);
-    SPRINTF("        command = ");
-    command = cmd->cmnd;
-    SPRINTF("%2d (0x%02x)", command[0], command[0]);
-    for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
-	SPRINTF(" %02x", command[i]);
-    SPRINTF("\n");
-    return pos;
+	int i, s;
+	unsigned char *command;
+	seq_printf(m, "scsi%d: destination target %d, lun %d\n",
+		H_NO(cmd), cmd->device->id, cmd->device->lun);
+	seq_printf(m, "        command = ");
+	command = cmd->cmnd;
+	seq_printf(m, "%2d (0x%02x)", command[0], command[0]);
+	for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
+		seq_printf(m, " %02x", command[i]);
+	seq_printf(m, "\n");
 }
 
+static int NCR5380_show_info(struct seq_file *m, struct Scsi_Host *instance)
+{
+	struct NCR5380_hostdata *hostdata;
+	Scsi_Cmnd *ptr;
+	unsigned long flags;
+
+	hostdata = (struct NCR5380_hostdata *)instance->hostdata;
+
+	seq_printf(m, "NCR5380 core release=%d.\n", NCR5380_PUBLIC_RELEASE);
+	local_irq_save(flags);
+	seq_printf(m, "NCR5380: coroutine is%s running.\n",
+		main_running ? "" : "n't");
+	if (!hostdata->connected)
+		seq_printf(m, "scsi%d: no currently connected command\n", HOSTNO);
+	else
+		show_Scsi_Cmnd((Scsi_Cmnd *) hostdata->connected, m);
+	seq_printf(m, "scsi%d: issue_queue\n", HOSTNO);
+	for (ptr = (Scsi_Cmnd *)hostdata->issue_queue; ptr; ptr = NEXT(ptr))
+		show_Scsi_Cmnd(ptr, m);
+
+	seq_printf(m, "scsi%d: disconnected_queue\n", HOSTNO);
+	for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
+	     ptr = NEXT(ptr))
+		show_Scsi_Cmnd(ptr, m);
+
+	local_irq_restore(flags);
+	return 0;
+}
 
 /* 
  * Function : void NCR5380_init (struct Scsi_Host *instance)
diff --git a/drivers/scsi/sun3_scsi.c b/drivers/scsi/sun3_scsi.c
index 6e25889db9d4..e2c009b033ce 100644
--- a/drivers/scsi/sun3_scsi.c
+++ b/drivers/scsi/sun3_scsi.c
@@ -626,6 +626,7 @@ static int sun3scsi_dma_finish(int write_flag)
 #include "sun3_NCR5380.c"
 
 static struct scsi_host_template driver_template = {
+	.show_info		= sun3scsi_show_info,
 	.name			= SUN3_SCSI_NAME,
 	.detect			= sun3scsi_detect,
 	.release		= sun3scsi_release,
diff --git a/drivers/scsi/sun3_scsi.h b/drivers/scsi/sun3_scsi.h
index bcefd8458e65..a8da9c710fea 100644
--- a/drivers/scsi/sun3_scsi.h
+++ b/drivers/scsi/sun3_scsi.h
@@ -100,7 +100,7 @@ static int sun3scsi_release (struct Scsi_Host *);
 #define NCR5380_queue_command sun3scsi_queue_command
 #define NCR5380_bus_reset sun3scsi_bus_reset
 #define NCR5380_abort sun3scsi_abort
-#define NCR5380_proc_info sun3scsi_proc_info
+#define NCR5380_show_info sun3scsi_show_info
 #define NCR5380_dma_xfer_len(i, cmd, phase) \
         sun3scsi_dma_xfer_len(cmd->SCp.this_residual,cmd,((phase) & SR_IO) ? 0 : 1)
 
diff --git a/fs/compat.c b/fs/compat.c
index d0560c93973d..93f7d021b716 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -67,8 +67,6 @@ int compat_printk(const char *fmt, ...)
 	return ret;
 }
 
-#include "read_write.h"
-
 /*
  * Not all architectures have sys_utime, so implement this in terms
  * of sys_utimes.
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 3ced75f765ca..996cdc5abb85 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -608,7 +608,6 @@ struct serial_struct32 {
 static int serial_struct_ioctl(unsigned fd, unsigned cmd,
 			struct serial_struct32 __user *ss32)
 {
-        typedef struct serial_struct SS;
         typedef struct serial_struct32 SS32;
         int err;
         struct serial_struct ss;
diff --git a/fs/coredump.c b/fs/coredump.c
index a9abe313e8d5..dafafbafa731 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -654,10 +654,11 @@ void do_coredump(siginfo_t *siginfo)
 		goto close_fail;
 	if (displaced)
 		put_files_struct(displaced);
-	file_start_write(cprm.file);
-	core_dumped = !dump_interrupted() && binfmt->core_dump(&cprm);
-	file_end_write(cprm.file);
-
+	if (!dump_interrupted()) {
+		file_start_write(cprm.file);
+		core_dumped = binfmt->core_dump(&cprm);
+		file_end_write(cprm.file);
+	}
 	if (ispipe && core_pipe_limit)
 		wait_for_dump_helpers(cprm.file);
 close_fail:
diff --git a/fs/dcache.c b/fs/dcache.c
index e689268046c3..f09b9085f7d8 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -337,23 +337,6 @@ static void dentry_lru_del(struct dentry *dentry)
 	}
 }
 
-/*
- * Remove a dentry that is unreferenced and about to be pruned
- * (unhashed and destroyed) from the LRU, and inform the file system.
- * This wrapper should be called _prior_ to unhashing a victim dentry.
- */
-static void dentry_lru_prune(struct dentry *dentry)
-{
-	if (!list_empty(&dentry->d_lru)) {
-		if (dentry->d_flags & DCACHE_OP_PRUNE)
-			dentry->d_op->d_prune(dentry);
-
-		spin_lock(&dcache_lru_lock);
-		__dentry_lru_del(dentry);
-		spin_unlock(&dcache_lru_lock);
-	}
-}
-
 static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list)
 {
 	spin_lock(&dcache_lru_lock);
@@ -486,11 +469,13 @@ relock:
 	if (ref)
 		dentry->d_count--;
 	/*
-	 * if dentry was on the d_lru list delete it from there.
 	 * inform the fs via d_prune that this dentry is about to be
 	 * unhashed and destroyed.
 	 */
-	dentry_lru_prune(dentry);
+	if (dentry->d_flags & DCACHE_OP_PRUNE)
+		dentry->d_op->d_prune(dentry);
+
+	dentry_lru_del(dentry);
 	/* if it was on the hash then remove it */
 	__d_drop(dentry);
 	return d_kill(dentry, parent);
@@ -919,11 +904,13 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
 			struct inode *inode;
 
 			/*
-			 * remove the dentry from the lru, and inform
-			 * the fs that this dentry is about to be
+			 * inform the fs that this dentry is about to be
 			 * unhashed and destroyed.
 			 */
-			dentry_lru_prune(dentry);
+			if (dentry->d_flags & DCACHE_OP_PRUNE)
+				dentry->d_op->d_prune(dentry);
+
+			dentry_lru_del(dentry);
 			__d_shrink(dentry);
 
 			if (dentry->d_count != 0) {
@@ -2410,8 +2397,7 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 	dentry->d_parent = dentry;
 	list_del_init(&dentry->d_u.d_child);
 	anon->d_parent = dparent;
-	list_del(&anon->d_u.d_child);
-	list_add(&anon->d_u.d_child, &dparent->d_subdirs);
+	list_move(&anon->d_u.d_child, &dparent->d_subdirs);
 
 	write_seqcount_end(&dentry->d_seq);
 	write_seqcount_end(&anon->d_seq);
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index 0f6e52d22b84..32f35f187989 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/magic.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/pagemap.h>
@@ -45,8 +46,6 @@ static const struct dentry_operations hostfs_dentry_ops = {
 static char *root_ino = "";
 static int append = 0;
 
-#define HOSTFS_SUPER_MAGIC 0x00c0ffee
-
 static const struct inode_operations hostfs_iops;
 static const struct inode_operations hostfs_dir_iops;
 static const struct inode_operations hostfs_link_iops;
@@ -121,7 +120,7 @@ static char *dentry_name(struct dentry *dentry)
 	if (!name)
 		return NULL;
 
-	return __dentry_name(dentry, name); /* will unlock */
+	return __dentry_name(dentry, name);
 }
 
 static char *inode_name(struct inode *ino)
@@ -229,10 +228,11 @@ static struct inode *hostfs_alloc_inode(struct super_block *sb)
 {
 	struct hostfs_inode_info *hi;
 
-	hi = kzalloc(sizeof(*hi), GFP_KERNEL);
+	hi = kmalloc(sizeof(*hi), GFP_KERNEL);
 	if (hi == NULL)
 		return NULL;
 	hi->fd = -1;
+	hi->mode = 0;
 	inode_init_once(&hi->vfs_inode);
 	return &hi->vfs_inode;
 }
diff --git a/fs/namespace.c b/fs/namespace.c
index b4f96a5230a3..7b1ca9ba0b0a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2284,12 +2284,11 @@ long do_mount(const char *dev_name, const char *dir_name,
 
 	retval = security_sb_mount(dev_name, &path,
 				   type_page, flags, data_page);
+	if (!retval && !may_mount())
+		retval = -EPERM;
 	if (retval)
 		goto dput_out;
 
-	if (!may_mount())
-		return -EPERM;
-
 	/* Default to relatime unless overriden */
 	if (!(flags & MS_NOATIME))
 		mnt_flags |= MNT_RELATIME;
@@ -2464,7 +2463,7 @@ static struct mnt_namespace *create_mnt_ns(struct vfsmount *m)
 		struct mount *mnt = real_mount(m);
 		mnt->mnt_ns = new_ns;
 		new_ns->root = mnt;
-		list_add(&new_ns->list, &mnt->mnt_list);
+		list_add(&mnt->mnt_list, &new_ns->list);
 	} else {
 		mntput(m);
 	}
diff --git a/fs/proc/proc_devtree.c b/fs/proc/proc_devtree.c
index 505afc950e0a..106a83570630 100644
--- a/fs/proc/proc_devtree.c
+++ b/fs/proc/proc_devtree.c
@@ -12,7 +12,7 @@
 #include <linux/stat.h>
 #include <linux/string.h>
 #include <linux/of.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/slab.h>
 #include <asm/prom.h>
 #include <asm/uaccess.h>
diff --git a/fs/read_write.c b/fs/read_write.c
index 605dbbcb1973..90ba3b350e50 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -16,12 +16,15 @@
 #include <linux/pagemap.h>
 #include <linux/splice.h>
 #include <linux/compat.h>
-#include "read_write.h"
 #include "internal.h"
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 
+typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
+typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
+		unsigned long, loff_t);
+
 const struct file_operations generic_ro_fops = {
 	.llseek		= generic_file_llseek,
 	.read		= do_sync_read,
diff --git a/fs/read_write.h b/fs/read_write.h
deleted file mode 100644
index 0ec530d9305b..000000000000
--- a/fs/read_write.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/*
- * This file is only for sharing some helpers from read_write.c with compat.c.
- * Don't use anywhere else.
- */
-
-
-typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
-typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
-		unsigned long, loff_t);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e8cd6b839675..b5a24ba83b6f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2227,6 +2227,13 @@ static inline void file_start_write(struct file *file)
 	__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
 }
 
+static inline bool file_start_write_trylock(struct file *file)
+{
+	if (!S_ISREG(file_inode(file)->i_mode))
+		return true;
+	return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
+}
+
 static inline void file_end_write(struct file *file)
 {
 	if (!S_ISREG(file_inode(file)->i_mode))
diff --git a/include/linux/nubus.h b/include/linux/nubus.h
index b3740527571a..6165b2c62040 100644
--- a/include/linux/nubus.h
+++ b/include/linux/nubus.h
@@ -87,7 +87,6 @@ static inline void nubus_proc_init(void) {}
 #endif
 int get_nubus_list(char *buf);
 int nubus_proc_attach_device(struct nubus_dev *dev);
-int nubus_proc_detach_device(struct nubus_dev *dev);
 /* If we need more precision we can add some more of these */
 struct nubus_dev* nubus_find_device(unsigned short category,
 				    unsigned short type,
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 249df3720be2..2944278a8ba7 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -30,6 +30,7 @@
 #define JFFS2_SUPER_MAGIC	0x72b6
 #define PSTOREFS_MAGIC		0x6165676C
 #define EFIVARFS_MAGIC		0xde5e81e4
+#define HOSTFS_SUPER_MAGIC	0x00c0ffee
 
 #define MINIX_SUPER_MAGIC	0x137F		/* minix v1 fs, 14 char names */
 #define MINIX_SUPER_MAGIC2	0x138F		/* minix v1 fs, 30 char names */
diff --git a/kernel/acct.c b/kernel/acct.c
index 85389fe2abd0..8d6e145138bb 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -540,10 +540,15 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	ac.ac_swaps = encode_comp_t(0);
 
 	/*
+	 * Get freeze protection. If the fs is frozen, just skip the write
+	 * as we could deadlock the system otherwise.
+	 */
+	if (!file_start_write_trylock(file))
+		goto out;
+	/*
 	 * Kernel segment override to datasegment and write it
 	 * to the accounting file.
 	 */
-	file_start_write(file);
 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	/*