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List:       jfs-patches
Subject:    [Jfs-patches] [PATCH 1/6] BKL-removal: Use unlocked_ioctl for jfs
From:       shaggy () linux ! vnet ! ibm ! com
Date:       2008-05-13 14:49:52
Message-ID: 20080513144952.8B98012FEA0 () norville ! austin ! ibm ! com
[Download RAW message or body]

BKL-removal: Use unlocked_ioctl for jfs

Convert jfs_ioctl over to not use the BKL. The only potential race
I could see was with two ioctls in parallel changing the flags
and losing the updates. Use the i_mutex to protect against this.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

---
commit 751a6509590ca0a9606e9091415b8920dc8922a4
tree aeb73b56ae07fcc81fc58a890887e15d5079a8d7
parent 91525300baf162e83e923b09ca286f9205e21522
author Andi Kleen <ak@suse.de> Sun, 27 Jan 2008 16:58:51 -0600
committer Dave Kleikamp <shaggy@linux.vnet.ibm.com> Sun, 27 Jan 2008 16:58:51 -0600

 fs/jfs/file.c      |    2 +-
 fs/jfs/ioctl.c     |   13 ++++++++++---
 fs/jfs/jfs_inode.h |    3 +--
 fs/jfs/namei.c     |    2 +-
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/jfs/file.c b/fs/jfs/file.c
index 87eb936..713ff4c 100644
--- a/fs/jfs/file.c
+++ b/fs/jfs/file.c
@@ -112,5 +112,5 @@ const struct file_operations jfs_file_operations = {
 	.splice_write	= generic_file_splice_write,
 	.fsync		= jfs_fsync,
 	.release	= jfs_release,
-	.ioctl		= jfs_ioctl,
+	.unlocked_ioctl = jfs_ioctl,
 };
diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
index dfda12a..fc82ecc 100644
--- a/fs/jfs/ioctl.c
+++ b/fs/jfs/ioctl.c
@@ -51,9 +51,9 @@ static long jfs_map_ext2(unsigned long flags, int from)
 }
 
 
-int jfs_ioctl(struct inode * inode, struct file * filp, unsigned int cmd,
-		unsigned long arg)
+long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
+	struct inode *inode = filp->f_dentry->d_inode;
 	struct jfs_inode_info *jfs_inode = JFS_IP(inode);
 	unsigned int flags;
 
@@ -82,6 +82,10 @@ int jfs_ioctl(struct inode * inode, struct file * filp, unsigned int cmd,
 		/* Is it quota file? Do not allow user to mess with it */
 		if (IS_NOQUOTA(inode))
 			return -EPERM;
+
+		/* Lock against other parallel changes of flags */
+		mutex_lock(&inode->i_mutex);
+
 		jfs_get_inode_flags(jfs_inode);
 		oldflags = jfs_inode->mode2;
 
@@ -92,8 +96,10 @@ int jfs_ioctl(struct inode * inode, struct file * filp, unsigned int cmd,
 		if ((oldflags & JFS_IMMUTABLE_FL) ||
 			((flags ^ oldflags) &
 			(JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
-			if (!capable(CAP_LINUX_IMMUTABLE))
+			if (!capable(CAP_LINUX_IMMUTABLE)) {
+				mutex_unlock(&inode->i_mutex);
 				return -EPERM;
+			}
 		}
 
 		flags = flags & JFS_FL_USER_MODIFIABLE;
@@ -101,6 +107,7 @@ int jfs_ioctl(struct inode * inode, struct file * filp, unsigned int cmd,
 		jfs_inode->mode2 = flags;
 
 		jfs_set_inode_flags(inode);
+		mutex_unlock(&inode->i_mutex);
 		inode->i_ctime = CURRENT_TIME_SEC;
 		mark_inode_dirty(inode);
 		return 0;
diff --git a/fs/jfs/jfs_inode.h b/fs/jfs/jfs_inode.h
index 8e2cf2c..c8c1826 100644
--- a/fs/jfs/jfs_inode.h
+++ b/fs/jfs/jfs_inode.h
@@ -22,8 +22,7 @@ struct fid;
 
 extern struct inode *ialloc(struct inode *, umode_t);
 extern int jfs_fsync(struct file *, struct dentry *, int);
-extern int jfs_ioctl(struct inode *, struct file *,
-			unsigned int, unsigned long);
+extern long jfs_ioctl(struct file *, unsigned int, unsigned long);
 extern void jfs_read_inode(struct inode *);
 extern int jfs_commit_inode(struct inode *, int);
 extern int jfs_write_inode(struct inode*, int);
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index f8718de..e5d0b61 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1562,7 +1562,7 @@ const struct file_operations jfs_dir_operations = {
 	.read		= generic_read_dir,
 	.readdir	= jfs_readdir,
 	.fsync		= jfs_fsync,
-	.ioctl		= jfs_ioctl,
+	.unlocked_ioctl = jfs_ioctl,
 };
 
 static int jfs_ci_hash(struct dentry *dir, struct qstr *this)

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