[PATCH] resierfs: avoid tail packing if an inode was ever mmapped

This patch fixes a confusion reiserfs has for a long time.

On release file operation reiserfs used to try to pack file data stored in
last incomplete page of some files into metadata blocks.  After packing the
page got cleared with clear_page_dirty.  It did not take into account that
the page may be mmaped into other process's address space.  Recent
replacement for clear_page_dirty cancel_dirty_page found the confusion with
sanity check that page has to be not mapped.

The patch fixes the confusion by making reiserfs avoid tail packing if an
inode was ever mmapped.  reiserfs_mmap and reiserfs_file_release are
serialized with mutex in reiserfs specific inode.  reiserfs_mmap locks the
mutex and sets a bit in reiserfs specific inode flags.
reiserfs_file_release checks the bit having the mutex locked.  If bit is
set - tail packing is avoided.  This eliminates a possibility that mmapped
page gets cancel_page_dirty-ed.

Signed-off-by: Vladimir Saveliev <vs@namesys.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Chris Mason <mason@suse.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/reiserfs/file.c b/fs/reiserfs/file.c
index 99b6f329ba23edc7b513e9b7dd606028497bb275..5109f1d5e7ffcbe2eb08340221439b440fd5ba57 100644 (file)
--- a/fs/reiserfs/file.c
+++ b/fs/reiserfs/file.c
@@ -48,6 +48,11 @@ static int reiserfs_file_release(struct inode *inode, struct file *filp)
        }
 
        mutex_lock(&inode->i_mutex);
+
+       mutex_lock(&(REISERFS_I(inode)->i_mmap));
+       if (REISERFS_I(inode)->i_flags & i_ever_mapped)
+               REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
+
        reiserfs_write_lock(inode->i_sb);
        /* freeing preallocation only involves relogging blocks that
         * are already in the current transaction.  preallocation gets
@@ -100,11 +105,24 @@ static int reiserfs_file_release(struct inode *inode, struct file *filp)
                err = reiserfs_truncate_file(inode, 0);
        }
       out:
+       mutex_unlock(&(REISERFS_I(inode)->i_mmap));
        mutex_unlock(&inode->i_mutex);
        reiserfs_write_unlock(inode->i_sb);
        return err;
 }
 
+static int reiserfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       struct inode *inode;
+
+       inode = file->f_path.dentry->d_inode;
+       mutex_lock(&(REISERFS_I(inode)->i_mmap));
+       REISERFS_I(inode)->i_flags |= i_ever_mapped;
+       mutex_unlock(&(REISERFS_I(inode)->i_mmap));
+
+       return generic_file_mmap(file, vma);
+}
+
 static void reiserfs_vfs_truncate_file(struct inode *inode)
 {
        reiserfs_truncate_file(inode, 1);
@@ -1527,7 +1545,7 @@ const struct file_operations reiserfs_file_operations = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = reiserfs_compat_ioctl,
 #endif
-       .mmap = generic_file_mmap,
+       .mmap = reiserfs_file_mmap,
        .open = generic_file_open,
        .release = reiserfs_file_release,
        .fsync = reiserfs_sync_file,

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index f3d1c4a77979d1506903c88df9c8cdc76c388a09..9fcbfe3169776516162b7a68bfbf845975adb639 100644 (file)
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -1125,6 +1125,7 @@ static void init_inode(struct inode *inode, struct treepath *path)
        REISERFS_I(inode)->i_prealloc_count = 0;
        REISERFS_I(inode)->i_trans_id = 0;
        REISERFS_I(inode)->i_jl = NULL;
+       mutex_init(&(REISERFS_I(inode)->i_mmap));
        reiserfs_init_acl_access(inode);
        reiserfs_init_acl_default(inode);
        reiserfs_init_xattr_rwsem(inode);
@@ -1832,6 +1833,7 @@ int reiserfs_new_inode(struct reiserfs_transaction_handle *th,
        REISERFS_I(inode)->i_attrs =
            REISERFS_I(dir)->i_attrs & REISERFS_INHERIT_MASK;
        sd_attrs_to_i_attrs(REISERFS_I(inode)->i_attrs, inode);
+       mutex_init(&(REISERFS_I(inode)->i_mmap));
        reiserfs_init_acl_access(inode);
        reiserfs_init_acl_default(inode);
        reiserfs_init_xattr_rwsem(inode);

diff --git a/include/linux/reiserfs_fs_i.h b/include/linux/reiserfs_fs_i.h
index 5b3b297aa2c5b647294e69ac0090cef6c0deeb16..ce3663fb0101dca7513183833b474424f4d10c54 100644 (file)
--- a/include/linux/reiserfs_fs_i.h
+++ b/include/linux/reiserfs_fs_i.h
@@ -25,6 +25,7 @@ typedef enum {
        i_link_saved_truncate_mask = 0x0020,
        i_has_xattr_dir = 0x0040,
        i_data_log = 0x0080,
+       i_ever_mapped = 0x0100
 } reiserfs_inode_flags;
 
 struct reiserfs_inode_info {
@@ -52,6 +53,7 @@ struct reiserfs_inode_info {
         ** flushed */
        unsigned long i_trans_id;
        struct reiserfs_journal_list *i_jl;
+       struct mutex i_mmap;
 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
        struct posix_acl *i_acl_access;
        struct posix_acl *i_acl_default;