In many cases the simple fallocate call is
a no op (since the file is already not sparse) or
can simply be converted from a sparse to a non-sparse
file if we are fallocating the whole file and keeping
the size.
Signed-off-by: Steven French <smfrench@xxxxxxxxx>
---
fs/cifs/smb2ops.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c5f521b..568f323 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1102,6 +1102,64 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
return rc;
}
+static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
+ loff_t off, loff_t len, bool keep_size)
+{
+ struct inode *inode;
+ struct cifsInodeInfo *cifsi;
+ struct cifsFileInfo *cfile = file->private_data;
+ long rc = -EOPNOTSUPP;
+ unsigned int xid;
+
+ xid = get_xid();
+
+ inode = cfile->dentry->d_inode;
+ cifsi = CIFS_I(inode);
+
+ /* if file not oplocked can't be sure whether asking to extend size */
+ if (!CIFS_CACHE_READ(cifsi))
+ if (keep_size == false)
+ return -EOPNOTSUPP;
+
+ /*
+ * Files are non-sparse by default so falloc may be a no-op
+ * Must check if file sparse. If not sparse, and not extending
+ * then no need to do anything since file already allocated
+ */
+ if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {
+ if (keep_size == true)
+ return 0;
+ /* check if extending file */
+ else if (i_size_read(inode) >= off + len)
+ /* not extending file and already not sparse */
+ return 0;
+ /* BB: in future add else clause to extend file */
+ else
+ return -EOPNOTSUPP;
+ }
+
+ if ((keep_size == true) || (i_size_read(inode) >= off + len)) {
+ /*
+ * Check if falloc starts within first few pages of file
+ * and ends within a few pages of the end of file to
+ * ensure that most of file is being forced to be
+ * fallocated now. If so then setting whole file sparse
+ * ie potentially making a few extra pages at the beginning
+ * or end of the file non-sparse via set_sparse is harmless.
+ */
+ if ((off > 8192) || (off + len + 8192 < i_size_read(inode)))
+ return -EOPNOTSUPP;
+
+ rc = smb2_set_sparse(xid, tcon, cfile, inode, false);
+ }
+ /* BB: else ... in future add code to extend file and set sparse */
+
+
+ free_xid(xid);
+ return rc;
+}
+
+
static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
loff_t off, loff_t len)
{
@@ -1112,7 +1170,10 @@ static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
if (mode & FALLOC_FL_KEEP_SIZE)
return smb3_zero_range(file, tcon, off, len, true);
return smb3_zero_range(file, tcon, off, len, false);
- }
+ } else if (mode == FALLOC_FL_KEEP_SIZE)
+ return smb3_simple_falloc(file, tcon, off, len, true);
+ else if (mode == 0)
+ return smb3_simple_falloc(file, tcon, off, len, false);
return -EOPNOTSUPP;
}
--
1.9.1
--
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