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ANDROID: sdcardfs: Hold i_mutex for i_size_write 

When we call i_size_write, we must be holding i_mutex to avoid
possible lockups on 32 bit/SMP architectures. This is not
necessary on 64 bit architectures.

Change-Id: Ic3b946507c54d81b5c9046f9b57d25d4b0f9feef
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Bug: 73287721
This commit is contained in:
Daniel Rosenberg 2018-02-20 20:25:45 -08:00 committed by syphyr
parent 22892f13df
commit 8f3de9844a
1 changed files with 7 additions and 4 deletions
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11
fs/sdcardfs/file.c
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@ -62,6 +62,7 @@ static ssize_t sdcardfs_write(struct file *file, const char __user *buf,
int err = 0;
struct file *lower_file;
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
/* check disk space */
if (!check_min_free_space(dentry, count, 0)) {
@ -73,10 +74,12 @@ static ssize_t sdcardfs_write(struct file *file, const char __user *buf,
err = vfs_write(lower_file, buf, count, ppos);
/* update our inode times+sizes upon a successful lower write */
if (err >= 0) {
fsstack_copy_inode_size(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
fsstack_copy_attr_times(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
if (sizeof(loff_t) > sizeof(long))
mutex_lock(&inode->i_mutex);
fsstack_copy_inode_size(inode, file_inode(lower_file));
fsstack_copy_attr_times(inode, file_inode(lower_file));
if (sizeof(loff_t) > sizeof(long))
mutex_unlock(&inode->i_mutex);
}
return err;