When UBIFS is using 64bit cookies for directory offsets,
we have to support seeking that deep into direcoties.
Since generic_file_llseek() is uses sb->s_maxbytes it will
fail for use because on ubifs sb->s_maxbytes is the real maxmal
file size which can be much smaller than 64bit due to limitations
of the flash device.
Therefore provie a custom llseek operation.
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
fs/ubifs/dir.c | 12 +++++++++++-
fs/ubifs/ubifs-media.h | 6 ++++++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 566079d9b402..cada60690c22 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1686,6 +1686,16 @@ static int ubifs_dir_open(struct inode *dir, struct file *file)
return 0;
}
+static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_mapping->host;
+
+ return generic_file_llseek_size(file, offset, whence,
+ (loff_t)UBIFS_S_KEY_HASH_MASK <<
+ UBIFS_DH_BITS | UBIFS_DH_MASK,
+ i_size_read(inode));
+}
+
const struct inode_operations ubifs_dir_inode_operations = {
.lookup = ubifs_lookup,
.create = ubifs_create,
@@ -1706,7 +1716,7 @@ const struct inode_operations ubifs_dir_inode_operations = {
};
const struct file_operations ubifs_dir_operations = {
- .llseek = generic_file_llseek,
+ .llseek = ubifs_dir_llseek,
.release = ubifs_dir_release,
.read = generic_read_dir,
.iterate_shared = ubifs_readdir,
diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index e8c23c9d4f4a..5939776c7359 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -214,6 +214,12 @@ enum {
#define UBIFS_S_KEY_HASH_MASK UBIFS_S_KEY_BLOCK_MASK
/*
+ * We use 32 bits for the double hash cookie.
+ */
+#define UBIFS_DH_MASK 0xffffffff
+#define UBIFS_DH_BITS 32
+
+/*
* Key types.
*
* UBIFS_INO_KEY: inode node key
--
2.12.0
