[PATCH 2/6] ubifs: Provide a custom llseek for directories

2017-05-21 Thread Richard Weinberger
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 
---
 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 0x
+#define UBIFS_DH_BITS 32
+
+/*
  * Key types.
  *
  * UBIFS_INO_KEY: inode node key
-- 
2.12.0



[PATCH 2/6] ubifs: Provide a custom llseek for directories

2016-12-01 Thread Richard Weinberger
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 
---
 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 7f01f3d2ac3b..883b2fdf51df 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1721,6 +1721,16 @@ 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,
@@ -1741,7 +1751,7 @@ 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 0x
+#define UBIFS_DH_BITS 32
+
+/*
  * Key types.
  *
  * UBIFS_INO_KEY: inode node key
-- 
2.7.3