tree: git://git.samba.org/sfrench/cifs-2.6.git for-next
head: 92129244f4fd2b0b4c02c99001ccb8303df28fcb
commit: 92129244f4fd2b0b4c02c99001ccb8303df28fcb [9/9] cifs: fix smb3-encryption crashes with CONFIG_DEBUG_SG
config: i386-randconfig-x007-201807 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
git checkout 92129244f4fd2b0b4c02c99001ccb8303df28fcb
# save the attached .config to linux build tree
make ARCH=i386
Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
All warnings (new ones prefixed by >>):
fs/cifs/smb2ops.c: In function 'smb3_punch_hole':
fs/cifs/smb2ops.c:1788:6: warning: statement with no effect [-Wunused-value]
rc -ENOMEM;
fs/cifs/smb2ops.c: In function 'smb3_fallocate':
>> fs/cifs/smb2ops.c:1867:10: warning: 'rc' may be used uninitialized in this function [-Wmaybe-uninitialized]
return smb3_punch_hole(file, tcon, off, len);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/rc +1867 fs/cifs/smb2ops.c
30175628b Steve French 2014-08-17 1760
31742c5a3 Steve French 2014-08-17 1761 static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
31742c5a3 Steve French 2014-08-17 1762 loff_t offset, loff_t len)
31742c5a3 Steve French 2014-08-17 1763 {
31742c5a3 Steve French 2014-08-17 1764 struct inode *inode;
31742c5a3 Steve French 2014-08-17 1765 struct cifsInodeInfo *cifsi;
31742c5a3 Steve French 2014-08-17 1766 struct cifsFileInfo *cfile = file->private_data;
92129244f Ronnie Sahlberg 2018-02-19 1767 struct file_zero_data_information *fsctl_buf;
31742c5a3 Steve French 2014-08-17 1768 long rc;
31742c5a3 Steve French 2014-08-17 1769 unsigned int xid;
31742c5a3 Steve French 2014-08-17 1770
31742c5a3 Steve French 2014-08-17 1771 xid = get_xid();
31742c5a3 Steve French 2014-08-17 1772
2b0143b5c David Howells 2015-03-17 1773 inode = d_inode(cfile->dentry);
31742c5a3 Steve French 2014-08-17 1774 cifsi = CIFS_I(inode);
31742c5a3 Steve French 2014-08-17 1775
31742c5a3 Steve French 2014-08-17 1776 /* Need to make file sparse, if not already, before freeing range. */
31742c5a3 Steve French 2014-08-17 1777 /* Consider adding equivalent for compressed since it could also work */
92129244f Ronnie Sahlberg 2018-02-19 1778 if (!smb2_set_sparse(xid, tcon, cfile, inode, 1)) {
92129244f Ronnie Sahlberg 2018-02-19 1779 rc = -EOPNOTSUPP;
92129244f Ronnie Sahlberg 2018-02-19 1780 goto out;
92129244f Ronnie Sahlberg 2018-02-19 1781 }
31742c5a3 Steve French 2014-08-17 1782 cifs_dbg(FYI, "offset %lld len %lld", offset, len);
31742c5a3 Steve French 2014-08-17 1783
92129244f Ronnie Sahlberg 2018-02-19 1784 fsctl_buf = kzalloc(sizeof(struct file_zero_data_information),
92129244f Ronnie Sahlberg 2018-02-19 1785 GFP_KERNEL);
92129244f Ronnie Sahlberg 2018-02-19 1786 if (!fsctl_buf) {
92129244f Ronnie Sahlberg 2018-02-19 1787 cifs_dbg(VFS, "failed to allocate fsctl_buf\n");
92129244f Ronnie Sahlberg 2018-02-19 @1788 rc -ENOMEM;
92129244f Ronnie Sahlberg 2018-02-19 1789 goto out;
92129244f Ronnie Sahlberg 2018-02-19 1790 }
92129244f Ronnie Sahlberg 2018-02-19 1791 fsctl_buf->FileOffset = cpu_to_le64(offset);
92129244f Ronnie Sahlberg 2018-02-19 1792 fsctl_buf->BeyondFinalZero = cpu_to_le64(offset + len);
31742c5a3 Steve French 2014-08-17 1793
31742c5a3 Steve French 2014-08-17 1794 rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
31742c5a3 Steve French 2014-08-17 1795 cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
92129244f Ronnie Sahlberg 2018-02-19 1796 true /* is_fctl */, (char *)fsctl_buf,
31742c5a3 Steve French 2014-08-17 1797 sizeof(struct file_zero_data_information), NULL, NULL);
92129244f Ronnie Sahlberg 2018-02-19 1798 kfree(fsctl_buf);
92129244f Ronnie Sahlberg 2018-02-19 1799 out:
31742c5a3 Steve French 2014-08-17 1800 free_xid(xid);
31742c5a3 Steve French 2014-08-17 1801 return rc;
31742c5a3 Steve French 2014-08-17 1802 }
31742c5a3 Steve French 2014-08-17 1803
9ccf32162 Steve French 2014-10-18 1804 static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
9ccf32162 Steve French 2014-10-18 1805 loff_t off, loff_t len, bool keep_size)
9ccf32162 Steve French 2014-10-18 1806 {
9ccf32162 Steve French 2014-10-18 1807 struct inode *inode;
9ccf32162 Steve French 2014-10-18 1808 struct cifsInodeInfo *cifsi;
9ccf32162 Steve French 2014-10-18 1809 struct cifsFileInfo *cfile = file->private_data;
9ccf32162 Steve French 2014-10-18 1810 long rc = -EOPNOTSUPP;
9ccf32162 Steve French 2014-10-18 1811 unsigned int xid;
9ccf32162 Steve French 2014-10-18 1812
9ccf32162 Steve French 2014-10-18 1813 xid = get_xid();
9ccf32162 Steve French 2014-10-18 1814
2b0143b5c David Howells 2015-03-17 1815 inode = d_inode(cfile->dentry);
9ccf32162 Steve French 2014-10-18 1816 cifsi = CIFS_I(inode);
9ccf32162 Steve French 2014-10-18 1817
9ccf32162 Steve French 2014-10-18 1818 /* if file not oplocked can't be sure whether asking to extend size */
9ccf32162 Steve French 2014-10-18 1819 if (!CIFS_CACHE_READ(cifsi))
9ccf32162 Steve French 2014-10-18 1820 if (keep_size == false)
9ccf32162 Steve French 2014-10-18 1821 return -EOPNOTSUPP;
9ccf32162 Steve French 2014-10-18 1822
9ccf32162 Steve French 2014-10-18 1823 /*
9ccf32162 Steve French 2014-10-18 1824 * Files are non-sparse by default so falloc may be a no-op
9ccf32162 Steve French 2014-10-18 1825 * Must check if file sparse. If not sparse, and not extending
9ccf32162 Steve French 2014-10-18 1826 * then no need to do anything since file already allocated
9ccf32162 Steve French 2014-10-18 1827 */
9ccf32162 Steve French 2014-10-18 1828 if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {
9ccf32162 Steve French 2014-10-18 1829 if (keep_size == true)
9ccf32162 Steve French 2014-10-18 1830 return 0;
9ccf32162 Steve French 2014-10-18 1831 /* check if extending file */
9ccf32162 Steve French 2014-10-18 1832 else if (i_size_read(inode) >= off + len)
9ccf32162 Steve French 2014-10-18 1833 /* not extending file and already not sparse */
9ccf32162 Steve French 2014-10-18 1834 return 0;
9ccf32162 Steve French 2014-10-18 1835 /* BB: in future add else clause to extend file */
9ccf32162 Steve French 2014-10-18 1836 else
9ccf32162 Steve French 2014-10-18 1837 return -EOPNOTSUPP;
9ccf32162 Steve French 2014-10-18 1838 }
9ccf32162 Steve French 2014-10-18 1839
9ccf32162 Steve French 2014-10-18 1840 if ((keep_size == true) || (i_size_read(inode) >= off + len)) {
9ccf32162 Steve French 2014-10-18 1841 /*
9ccf32162 Steve French 2014-10-18 1842 * Check if falloc starts within first few pages of file
9ccf32162 Steve French 2014-10-18 1843 * and ends within a few pages of the end of file to
9ccf32162 Steve French 2014-10-18 1844 * ensure that most of file is being forced to be
9ccf32162 Steve French 2014-10-18 1845 * fallocated now. If so then setting whole file sparse
9ccf32162 Steve French 2014-10-18 1846 * ie potentially making a few extra pages at the beginning
9ccf32162 Steve French 2014-10-18 1847 * or end of the file non-sparse via set_sparse is harmless.
9ccf32162 Steve French 2014-10-18 1848 */
9ccf32162 Steve French 2014-10-18 1849 if ((off > 8192) || (off + len + 8192 < i_size_read(inode)))
9ccf32162 Steve French 2014-10-18 1850 return -EOPNOTSUPP;
9ccf32162 Steve French 2014-10-18 1851
92129244f Ronnie Sahlberg 2018-02-19 1852 rc = smb2_set_sparse(xid, tcon, cfile, inode, 0);
9ccf32162 Steve French 2014-10-18 1853 }
9ccf32162 Steve French 2014-10-18 1854 /* BB: else ... in future add code to extend file and set sparse */
9ccf32162 Steve French 2014-10-18 1855
9ccf32162 Steve French 2014-10-18 1856
9ccf32162 Steve French 2014-10-18 1857 free_xid(xid);
9ccf32162 Steve French 2014-10-18 1858 return rc;
9ccf32162 Steve French 2014-10-18 1859 }
9ccf32162 Steve French 2014-10-18 1860
9ccf32162 Steve French 2014-10-18 1861
31742c5a3 Steve French 2014-08-17 1862 static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
31742c5a3 Steve French 2014-08-17 1863 loff_t off, loff_t len)
31742c5a3 Steve French 2014-08-17 1864 {
31742c5a3 Steve French 2014-08-17 1865 /* KEEP_SIZE already checked for by do_fallocate */
31742c5a3 Steve French 2014-08-17 1866 if (mode & FALLOC_FL_PUNCH_HOLE)
31742c5a3 Steve French 2014-08-17 @1867 return smb3_punch_hole(file, tcon, off, len);
30175628b Steve French 2014-08-17 1868 else if (mode & FALLOC_FL_ZERO_RANGE) {
30175628b Steve French 2014-08-17 1869 if (mode & FALLOC_FL_KEEP_SIZE)
30175628b Steve French 2014-08-17 1870 return smb3_zero_range(file, tcon, off, len, true);
30175628b Steve French 2014-08-17 1871 return smb3_zero_range(file, tcon, off, len, false);
9ccf32162 Steve French 2014-10-18 1872 } else if (mode == FALLOC_FL_KEEP_SIZE)
9ccf32162 Steve French 2014-10-18 1873 return smb3_simple_falloc(file, tcon, off, len, true);
9ccf32162 Steve French 2014-10-18 1874 else if (mode == 0)
9ccf32162 Steve French 2014-10-18 1875 return smb3_simple_falloc(file, tcon, off, len, false);
31742c5a3 Steve French 2014-08-17 1876
31742c5a3 Steve French 2014-08-17 1877 return -EOPNOTSUPP;
31742c5a3 Steve French 2014-08-17 1878 }
31742c5a3 Steve French 2014-08-17 1879
:::::: The code at line 1867 was first introduced by commit
:::::: 31742c5a331766bc7df6b0d525df00c6cd20d5a6 enable fallocate punch hole ("fallocate -p") for SMB3
:::::: TO: Steve French <smfrench@xxxxxxxxx>
:::::: CC: Steve French <smfrench@xxxxxxxxx>
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