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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 03:07:40 +0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 03:07:40 +0400
commit541010e4b8921cd781ff02ae68028501457045b6 (patch)
tree58bd529d4c6e69899a0aa20afa2d7f1c23326417
parente457f790d8b05977853aa238bbc667b3bb375671 (diff)
parent5e7fc436426b1f9e106f511a049de91c82ec2c53 (diff)
downloadlinux-541010e4b8921cd781ff02ae68028501457045b6.tar.xz
Merge branch 'locks' of git://linux-nfs.org/~bfields/linux
* 'locks' of git://linux-nfs.org/~bfields/linux: nfsd: remove IS_ISMNDLCK macro Rework /proc/locks via seq_files and seq_list helpers fs/locks.c: use list_for_each_entry() instead of list_for_each() NFS: clean up explicit check for mandatory locks AFS: clean up explicit check for mandatory locks 9PFS: clean up explicit check for mandatory locks GFS2: clean up explicit check for mandatory locks Cleanup macros for distinguishing mandatory locks Documentation: move locks.txt in filesystems/ locks: add warning about mandatory locking races Documentation: move mandatory locking documentation to filesystems/ locks: Fix potential OOPS in generic_setlease() Use list_first_entry in locks_wake_up_blocks locks: fix flock_lock_file() comment Memory shortage can result in inconsistent flocks state locks: kill redundant local variable locks: reverse order of posix_locks_conflict() arguments
-rw-r--r--Documentation/00-INDEX6
-rw-r--r--Documentation/filesystems/00-INDEX4
-rw-r--r--Documentation/filesystems/locks.txt (renamed from Documentation/locks.txt)10
-rw-r--r--Documentation/filesystems/mandatory-locking.txt (renamed from Documentation/mandatory.txt)21
-rw-r--r--fs/9p/vfs_file.c2
-rw-r--r--fs/afs/flock.c3
-rw-r--r--fs/gfs2/ops_file.c4
-rw-r--r--fs/locks.c192
-rw-r--r--fs/nfs/file.c3
-rw-r--r--fs/nfsd/nfs4state.c2
-rw-r--r--fs/nfsd/vfs.c13
-rw-r--r--fs/proc/proc_misc.c19
-rw-r--r--fs/read_write.c2
-rw-r--r--include/linux/fs.h22
14 files changed, 157 insertions, 146 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index 43e89b1537d9..cc10ce7dc339 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -145,7 +145,7 @@ fb/
feature-removal-schedule.txt
- list of files and features that are going to be removed.
filesystems/
- - directory with info on the various filesystems that Linux supports.
+ - info on the vfs and the various filesystems that Linux supports.
firmware_class/
- request_firmware() hotplug interface info.
floppy.txt
@@ -230,8 +230,6 @@ local_ops.txt
- semantics and behavior of local atomic operations.
lockdep-design.txt
- documentation on the runtime locking correctness validator.
-locks.txt
- - info on file locking implementations, flock() vs. fcntl(), etc.
logo.gif
- full colour GIF image of Linux logo (penguin - Tux).
logo.txt
@@ -240,8 +238,6 @@ m68k/
- directory with info about Linux on Motorola 68k architecture.
magic-number.txt
- list of magic numbers used to mark/protect kernel data structures.
-mandatory.txt
- - info on the Linux implementation of Sys V mandatory file locking.
mca.txt
- info on supporting Micro Channel Architecture (e.g. PS/2) systems.
md.txt
diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index 59db1bca7027..599593a17067 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -52,6 +52,10 @@ isofs.txt
- info and mount options for the ISO 9660 (CDROM) filesystem.
jfs.txt
- info and mount options for the JFS filesystem.
+locks.txt
+ - info on file locking implementations, flock() vs. fcntl(), etc.
+mandatory-locking.txt
+ - info on the Linux implementation of Sys V mandatory file locking.
ncpfs.txt
- info on Novell Netware(tm) filesystem using NCP protocol.
ntfs.txt
diff --git a/Documentation/locks.txt b/Documentation/filesystems/locks.txt
index e3b402ef33bd..fab857accbd6 100644
--- a/Documentation/locks.txt
+++ b/Documentation/filesystems/locks.txt
@@ -53,11 +53,11 @@ fcntl(), with all the problems that implies.
1.3 Mandatory Locking As A Mount Option
---------------------------------------
-Mandatory locking, as described in 'Documentation/mandatory.txt' was prior
-to this release a general configuration option that was valid for all
-mounted filesystems. This had a number of inherent dangers, not the least
-of which was the ability to freeze an NFS server by asking it to read a
-file for which a mandatory lock existed.
+Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt'
+was prior to this release a general configuration option that was valid for
+all mounted filesystems. This had a number of inherent dangers, not the
+least of which was the ability to freeze an NFS server by asking it to read
+a file for which a mandatory lock existed.
From this release of the kernel, mandatory locking can be turned on and off
on a per-filesystem basis, using the mount options 'mand' and 'nomand'.
diff --git a/Documentation/mandatory.txt b/Documentation/filesystems/mandatory-locking.txt
index bc449d49eee5..0979d1d2ca8b 100644
--- a/Documentation/mandatory.txt
+++ b/Documentation/filesystems/mandatory-locking.txt
@@ -3,7 +3,26 @@
Andy Walker <andy@lysaker.kvaerner.no>
15 April 1996
-
+ (Updated September 2007)
+
+0. Why you should avoid mandatory locking
+-----------------------------------------
+
+The Linux implementation is prey to a number of difficult-to-fix race
+conditions which in practice make it not dependable:
+
+ - The write system call checks for a mandatory lock only once
+ at its start. It is therefore possible for a lock request to
+ be granted after this check but before the data is modified.
+ A process may then see file data change even while a mandatory
+ lock was held.
+ - Similarly, an exclusive lock may be granted on a file after
+ the kernel has decided to proceed with a read, but before the
+ read has actually completed, and the reading process may see
+ the file data in a state which should not have been visible
+ to it.
+ - Similar races make the claimed mutual exclusion between lock
+ and mmap similarly unreliable.
1. What is mandatory locking?
------------------------------
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 2a40c2946d0a..716691689fd5 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -105,7 +105,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
/* No mandatory locks */
- if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__mandatory_lock(inode))
return -ENOLCK;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
diff --git a/fs/afs/flock.c b/fs/afs/flock.c
index af6952e39a18..210acafe4a9b 100644
--- a/fs/afs/flock.c
+++ b/fs/afs/flock.c
@@ -524,8 +524,7 @@ int afs_lock(struct file *file, int cmd, struct file_lock *fl)
(long long) fl->fl_start, (long long) fl->fl_end);
/* AFS doesn't support mandatory locks */
- if ((vnode->vfs_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- fl->fl_type != F_UNLCK)
+ if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
return -ENOLCK;
if (IS_GETLK(cmd))
diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index 46a9e10ff17b..7eb4b280ac66 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -535,7 +535,7 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
if (!(fl->fl_flags & FL_POSIX))
return -ENOLCK;
- if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__mandatory_lock(&ip->i_inode))
return -ENOLCK;
if (sdp->sd_args.ar_localflocks) {
@@ -636,7 +636,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
if (!(fl->fl_flags & FL_FLOCK))
return -ENOLCK;
- if ((ip->i_inode.i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__mandatory_lock(&ip->i_inode))
return -ENOLCK;
if (sdp->sd_args.ar_localflocks)
diff --git a/fs/locks.c b/fs/locks.c
index c795eaaf6c4c..7f9a3ea47418 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -534,7 +534,9 @@ static void locks_insert_block(struct file_lock *blocker,
static void locks_wake_up_blocks(struct file_lock *blocker)
{
while (!list_empty(&blocker->fl_block)) {
- struct file_lock *waiter = list_entry(blocker->fl_block.next,
+ struct file_lock *waiter;
+
+ waiter = list_first_entry(&blocker->fl_block,
struct file_lock, fl_block);
__locks_delete_block(waiter);
if (waiter->fl_lmops && waiter->fl_lmops->fl_notify)
@@ -668,7 +670,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {
if (!IS_POSIX(cfl))
continue;
- if (posix_locks_conflict(cfl, fl))
+ if (posix_locks_conflict(fl, cfl))
break;
}
if (cfl)
@@ -698,13 +700,12 @@ EXPORT_SYMBOL(posix_test_lock);
static int posix_locks_deadlock(struct file_lock *caller_fl,
struct file_lock *block_fl)
{
- struct list_head *tmp;
+ struct file_lock *fl;
next_task:
if (posix_same_owner(caller_fl, block_fl))
return 1;
- list_for_each(tmp, &blocked_list) {
- struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
+ list_for_each_entry(fl, &blocked_list, fl_link) {
if (posix_same_owner(fl, block_fl)) {
fl = fl->fl_next;
block_fl = fl;
@@ -715,8 +716,7 @@ next_task:
}
/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
- * at the head of the list, but that's secret knowledge known only to
- * flock_lock_file and posix_lock_file.
+ * after any leases, but before any posix locks.
*
* Note that if called with an FL_EXISTS argument, the caller may determine
* whether or not a lock was successfully freed by testing the return
@@ -733,6 +733,15 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
lock_kernel();
if (request->fl_flags & FL_ACCESS)
goto find_conflict;
+
+ if (request->fl_type != F_UNLCK) {
+ error = -ENOMEM;
+ new_fl = locks_alloc_lock();
+ if (new_fl == NULL)
+ goto out;
+ error = 0;
+ }
+
for_each_lock(inode, before) {
struct file_lock *fl = *before;
if (IS_POSIX(fl))
@@ -754,10 +763,6 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
goto out;
}
- error = -ENOMEM;
- new_fl = locks_alloc_lock();
- if (new_fl == NULL)
- goto out;
/*
* If a higher-priority process was blocked on the old file lock,
* give it the opportunity to lock the file.
@@ -819,7 +824,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
lock_kernel();
if (request->fl_type != F_UNLCK) {
for_each_lock(inode, before) {
- struct file_lock *fl = *before;
+ fl = *before;
if (!IS_POSIX(fl))
continue;
if (!posix_locks_conflict(request, fl))
@@ -1113,7 +1118,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
* If we've been sleeping someone might have
* changed the permissions behind our back.
*/
- if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+ if (__mandatory_lock(inode))
continue;
}
@@ -1337,6 +1342,7 @@ int fcntl_getlease(struct file *filp)
int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
{
struct file_lock *fl, **before, **my_before = NULL, *lease;
+ struct file_lock *new_fl = NULL;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
int error, rdlease_count = 0, wrlease_count = 0;
@@ -1363,6 +1369,11 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
|| (atomic_read(&inode->i_count) > 1)))
goto out;
+ error = -ENOMEM;
+ new_fl = locks_alloc_lock();
+ if (new_fl == NULL)
+ goto out;
+
/*
* At this point, we know that if there is an exclusive
* lease on this file, then we hold it on this filp
@@ -1405,18 +1416,15 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
if (!leases_enable)
goto out;
- error = -ENOMEM;
- fl = locks_alloc_lock();
- if (fl == NULL)
- goto out;
-
- locks_copy_lock(fl, lease);
+ locks_copy_lock(new_fl, lease);
+ locks_insert_lock(before, new_fl);
- locks_insert_lock(before, fl);
+ *flp = new_fl;
+ return 0;
- *flp = fl;
- error = 0;
out:
+ if (new_fl != NULL)
+ locks_free_lock(new_fl);
return error;
}
EXPORT_SYMBOL(generic_setlease);
@@ -1752,9 +1760,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
@@ -1878,9 +1884,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
/* Don't allow mandatory locks on files that may be memory mapped
* and shared.
*/
- if (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- mapping_writably_mapped(filp->f_mapping)) {
+ if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
error = -EAGAIN;
goto out;
}
@@ -2062,138 +2066,114 @@ int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
EXPORT_SYMBOL_GPL(vfs_cancel_lock);
-static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx)
+#ifdef CONFIG_PROC_FS
+#include <linux/seq_file.h>
+
+static void lock_get_status(struct seq_file *f, struct file_lock *fl,
+ int id, char *pfx)
{
struct inode *inode = NULL;
if (fl->fl_file != NULL)
inode = fl->fl_file->f_path.dentry->d_inode;
- out += sprintf(out, "%d:%s ", id, pfx);
+ seq_printf(f, "%d:%s ", id, pfx);
if (IS_POSIX(fl)) {
- out += sprintf(out, "%6s %s ",
+ seq_printf(f, "%6s %s ",
(fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
(inode == NULL) ? "*NOINODE*" :
- (IS_MANDLOCK(inode) &&
- (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ?
- "MANDATORY" : "ADVISORY ");
+ mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
if (fl->fl_type & LOCK_MAND) {
- out += sprintf(out, "FLOCK MSNFS ");
+ seq_printf(f, "FLOCK MSNFS ");
} else {
- out += sprintf(out, "FLOCK ADVISORY ");
+ seq_printf(f, "FLOCK ADVISORY ");
}
} else if (IS_LEASE(fl)) {
- out += sprintf(out, "LEASE ");
+ seq_printf(f, "LEASE ");
if (fl->fl_type & F_INPROGRESS)
- out += sprintf(out, "BREAKING ");
+ seq_printf(f, "BREAKING ");
else if (fl->fl_file)
- out += sprintf(out, "ACTIVE ");
+ seq_printf(f, "ACTIVE ");
else
- out += sprintf(out, "BREAKER ");
+ seq_printf(f, "BREAKER ");
} else {
- out += sprintf(out, "UNKNOWN UNKNOWN ");
+ seq_printf(f, "UNKNOWN UNKNOWN ");
}
if (fl->fl_type & LOCK_MAND) {
- out += sprintf(out, "%s ",
+ seq_printf(f, "%s ",
(fl->fl_type & LOCK_READ)
? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
: (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
} else {
- out += sprintf(out, "%s ",
+ seq_printf(f, "%s ",
(fl->fl_type & F_INPROGRESS)
? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ "
: (fl->fl_type & F_WRLCK) ? "WRITE" : "READ ");
}
if (inode) {
#ifdef WE_CAN_BREAK_LSLK_NOW
- out += sprintf(out, "%d %s:%ld ", fl->fl_pid,
+ seq_printf(f, "%d %s:%ld ", fl->fl_pid,
inode->i_sb->s_id, inode->i_ino);
#else
/* userspace relies on this representation of dev_t ;-( */
- out += sprintf(out, "%d %02x:%02x:%ld ", fl->fl_pid,
+ seq_printf(f, "%d %02x:%02x:%ld ", fl->fl_pid,
MAJOR(inode->i_sb->s_dev),
MINOR(inode->i_sb->s_dev), inode->i_ino);
#endif
} else {
- out += sprintf(out, "%d <none>:0 ", fl->fl_pid);
+ seq_printf(f, "%d <none>:0 ", fl->fl_pid);
}
if (IS_POSIX(fl)) {
if (fl->fl_end == OFFSET_MAX)
- out += sprintf(out, "%Ld EOF\n", fl->fl_start);
+ seq_printf(f, "%Ld EOF\n", fl->fl_start);
else
- out += sprintf(out, "%Ld %Ld\n", fl->fl_start,
- fl->fl_end);
+ seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
} else {
- out += sprintf(out, "0 EOF\n");
+ seq_printf(f, "0 EOF\n");
}
}
-static void move_lock_status(char **p, off_t* pos, off_t offset)
+static int locks_show(struct seq_file *f, void *v)
{
- int len;
- len = strlen(*p);
- if(*pos >= offset) {
- /* the complete line is valid */
- *p += len;
- *pos += len;
- return;
- }
- if(*pos+len > offset) {
- /* use the second part of the line */
- int i = offset-*pos;
- memmove(*p,*p+i,len-i);
- *p += len-i;
- *pos += len;
- return;
- }
- /* discard the complete line */
- *pos += len;
+ struct file_lock *fl, *bfl;
+
+ fl = list_entry(v, struct file_lock, fl_link);
+
+ lock_get_status(f, fl, (long)f->private, "");
+
+ list_for_each_entry(bfl, &fl->fl_block, fl_block)
+ lock_get_status(f, bfl, (long)f->private, " ->");
+
+ f->private++;
+ return 0;
}
-/**
- * get_locks_status - reports lock usage in /proc/locks
- * @buffer: address in userspace to write into
- * @start: ?
- * @offset: how far we are through the buffer
- * @length: how much to read
- */
+static void *locks_start(struct seq_file *f, loff_t *pos)
+{
+ lock_kernel();
+ f->private = (void *)1;
+ return seq_list_start(&file_lock_list, *pos);
+}
-int get_locks_status(char *buffer, char **start, off_t offset, int length)
+static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
{
- struct list_head *tmp;
- char *q = buffer;
- off_t pos = 0;
- int i = 0;
+ return seq_list_next(v, &file_lock_list, pos);
+}
- lock_kernel();
- list_for_each(tmp, &file_lock_list) {
- struct list_head *btmp;
- struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
- lock_get_status(q, fl, ++i, "");
- move_lock_status(&q, &pos, offset);
-
- if(pos >= offset+length)
- goto done;
-
- list_for_each(btmp, &fl->fl_block) {
- struct file_lock *bfl = list_entry(btmp,
- struct file_lock, fl_block);
- lock_get_status(q, bfl, i, " ->");
- move_lock_status(&q, &pos, offset);
-
- if(pos >= offset+length)
- goto done;
- }
- }
-done:
+static void locks_stop(struct seq_file *f, void *v)
+{
unlock_kernel();
- *start = buffer;
- if(q-buffer < length)
- return (q-buffer);
- return length;
}
+struct seq_operations locks_seq_operations = {
+ .start = locks_start,
+ .next = locks_next,
+ .stop = locks_stop,
+ .show = locks_show,
+};
+#endif
+
/**
* lock_may_read - checks that the region is free of locks
* @inode: the inode that is being read
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index c664bb921425..08c7c7387fce 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -577,8 +577,7 @@ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
nfs_inc_stats(inode, NFSIOS_VFSLOCK);
/* No mandatory locks over NFS */
- if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
- fl->fl_type != F_UNLCK)
+ if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
return -ENOLCK;
if (IS_GETLK(cmd))
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6f182d25793d..31673cd251c3 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2035,7 +2035,7 @@ static inline int
io_during_grace_disallowed(struct inode *inode, int flags)
{
return nfs4_in_grace() && (flags & (RD_STATE | WR_STATE))
- && MANDATORY_LOCK(inode);
+ && mandatory_lock(inode);
}
/*
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index cec78c82b1f9..2a8d665b134b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -61,12 +61,6 @@
#define NFSDDBG_FACILITY NFSDDBG_FILEOP
-/* We must ignore files (but only files) which might have mandatory
- * locks on them because there is no way to know if the accesser has
- * the lock.
- */
-#define IS_ISMNDLK(i) (S_ISREG((i)->i_mode) && MANDATORY_LOCK(i))
-
/*
* This is a cache of readahead params that help us choose the proper
* readahead strategy. Initially, we set all readahead parameters to 0
@@ -689,7 +683,12 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
err = nfserr_perm;
if (IS_APPEND(inode) && (access & MAY_WRITE))
goto out;
- if (IS_ISMNDLK(inode))
+ /*
+ * We must ignore files (but only files) which might have mandatory
+ * locks on them because there is no way to know if the accesser has
+ * the lock.
+ */
+ if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
goto out;
if (!inode->i_fop)
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index b872a01ad3af..0071939c0095 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -66,7 +66,6 @@ extern int get_stram_list(char *);
extern int get_filesystem_list(char *);
extern int get_exec_domain_list(char *);
extern int get_dma_list(char *);
-extern int get_locks_status (char *, char **, off_t, int);
static int proc_calc_metrics(char *page, char **start, off_t off,
int count, int *eof, int len)
@@ -624,16 +623,18 @@ static int cmdline_read_proc(char *page, char **start, off_t off,
return proc_calc_metrics(page, start, off, count, eof, len);
}
-static int locks_read_proc(char *page, char **start, off_t off,
- int count, int *eof, void *data)
+static int locks_open(struct inode *inode, struct file *filp)
{
- int len = get_locks_status(page, start, off, count);
-
- if (len < count)
- *eof = 1;
- return len;
+ return seq_open(filp, &locks_seq_operations);
}
+static const struct file_operations proc_locks_operations = {
+ .open = locks_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
static int execdomains_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
@@ -691,7 +692,6 @@ void __init proc_misc_init(void)
#endif
{"filesystems", filesystems_read_proc},
{"cmdline", cmdline_read_proc},
- {"locks", locks_read_proc},
{"execdomains", execdomains_read_proc},
{NULL,}
};
@@ -709,6 +709,7 @@ void __init proc_misc_init(void)
entry->proc_fops = &proc_kmsg_operations;
}
#endif
+ create_seq_entry("locks", 0, &proc_locks_operations);
create_seq_entry("devices", 0, &proc_devinfo_operations);
create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations);
#ifdef CONFIG_BLOCK
diff --git a/fs/read_write.c b/fs/read_write.c
index 507ddff48a9a..124693e8d3fa 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -205,7 +205,7 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
goto Einval;
- if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) {
+ if (unlikely(inode->i_flock && mandatory_lock(inode))) {
int retval = locks_mandatory_area(
read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
inode, file, pos, count);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6d760f1ad875..4a6a21077bae 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -883,6 +883,7 @@ extern int vfs_setlease(struct file *, long, struct file_lock **);
extern int lease_modify(struct file_lock **, int);
extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
extern int lock_may_write(struct inode *, loff_t start, unsigned long count);
+extern struct seq_operations locks_seq_operations;
struct fasync_struct {
int magic;
@@ -1375,12 +1376,25 @@ extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size
* Candidates for mandatory locking have the setgid bit set
* but no group execute bit - an otherwise meaningless combination.
*/
-#define MANDATORY_LOCK(inode) \
- (IS_MANDLOCK(inode) && ((inode)->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+
+static inline int __mandatory_lock(struct inode *ino)
+{
+ return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
+}
+
+/*
+ * ... and these candidates should be on MS_MANDLOCK mounted fs,
+ * otherwise these will be advisory locks
+ */
+
+static inline int mandatory_lock(struct inode *ino)
+{
+ return IS_MANDLOCK(ino) && __mandatory_lock(ino);
+}
static inline int locks_verify_locked(struct inode *inode)
{
- if (MANDATORY_LOCK(inode))
+ if (mandatory_lock(inode))
return locks_mandatory_locked(inode);
return 0;
}
@@ -1391,7 +1405,7 @@ static inline int locks_verify_truncate(struct inode *inode,
struct file *filp,
loff_t size)
{
- if (inode->i_flock && MANDATORY_LOCK(inode))
+ if (inode->i_flock && mandatory_lock(inode))
return locks_mandatory_area(
FLOCK_VERIFY_WRITE, inode, filp,
size < inode->i_size ? size : inode->i_size,