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[CIFS] Fix locking problem around some cifs uses of i_size write

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Could cause hangs on smp systems in i_size_read on a cifs inode
whose size has been previously simultaneously updated from
different processes.

Thanks to Brian Wang for some great testing/debugging on this
hard problem.

Fixes kernel bugzilla #7903

CC: Shirish Pargoankar <shirishp@us.ibm.com>
CC: Shaggy <shaggy@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Steve French
2007-02-26 16:46:11 +00:00
parent 9654640d0a
commit 3677db10a6
4 changed files with 82 additions and 23 deletions
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43
fs/cifs/file.c
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@@ -879,18 +879,19 @@ ssize_t cifs_user_write(struct file *file, const char __user *write_data,
cifs_stats_bytes_written(pTcon, total_written);
/* since the write may have blocked check these pointers again */
if (file->f_path.dentry) {
if (file->f_path.dentry->d_inode) {
struct inode *inode = file->f_path.dentry->d_inode;
inode->i_ctime = inode->i_mtime =
current_fs_time(inode->i_sb);
if (total_written > 0) {
if (*poffset > file->f_path.dentry->d_inode->i_size)
i_size_write(file->f_path.dentry->d_inode,
if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
struct inode *inode = file->f_path.dentry->d_inode;
/* Do not update local mtime - server will set its actual value on write
* inode->i_ctime = inode->i_mtime =
* current_fs_time(inode->i_sb);*/
if (total_written > 0) {
spin_lock(&inode->i_lock);
if (*poffset > file->f_path.dentry->d_inode->i_size)
i_size_write(file->f_path.dentry->d_inode,
*poffset);
}
mark_inode_dirty_sync(file->f_path.dentry->d_inode);
spin_unlock(&inode->i_lock);
}
mark_inode_dirty_sync(file->f_path.dentry->d_inode);
}
FreeXid(xid);
return total_written;
@@ -1012,18 +1013,18 @@ static ssize_t cifs_write(struct file *file, const char *write_data,
cifs_stats_bytes_written(pTcon, total_written);
/* since the write may have blocked check these pointers again */
if (file->f_path.dentry) {
if (file->f_path.dentry->d_inode) {
if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
/*BB We could make this contingent on superblock ATIME flag too */
/* file->f_path.dentry->d_inode->i_ctime =
file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
if (total_written > 0) {
if (*poffset > file->f_path.dentry->d_inode->i_size)
i_size_write(file->f_path.dentry->d_inode,
*poffset);
}
mark_inode_dirty_sync(file->f_path.dentry->d_inode);
/* file->f_path.dentry->d_inode->i_ctime =
file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
if (total_written > 0) {
spin_lock(&file->f_path.dentry->d_inode->i_lock);
if (*poffset > file->f_path.dentry->d_inode->i_size)
i_size_write(file->f_path.dentry->d_inode,
*poffset);
spin_unlock(&file->f_path.dentry->d_inode->i_lock);
}
mark_inode_dirty_sync(file->f_path.dentry->d_inode);
}
FreeXid(xid);
return total_written;
@@ -1400,6 +1401,7 @@ static int cifs_commit_write(struct file *file, struct page *page,
xid = GetXid();
cFYI(1, ("commit write for page %p up to position %lld for %d",
page, position, to));
spin_lock(&inode->i_lock);
if (position > inode->i_size) {
i_size_write(inode, position);
/* if (file->private_data == NULL) {
@@ -1429,6 +1431,7 @@ static int cifs_commit_write(struct file *file, struct page *page,
cFYI(1, (" SetEOF (commit write) rc = %d", rc));
} */
}
spin_unlock(&inode->i_lock);
if (!PageUptodate(page)) {
position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
/* can not rely on (or let) writepage write this data */