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authorAndi Kleen <ak@linux.intel.com>2011-09-15 16:06:50 -0700
committerroot <root@serles.lst.de>2011-10-28 14:58:59 +0200
commit5760495a872d63a182962680a13c2af29235237c (patch)
treeab7ac2b0ec66006efbc27c318c89474a63d6e4d1
parentef3d0fd27e90f67e35da516dafc1482c82939a60 (diff)
vfs: add generic_file_llseek_size
Add a generic_file_llseek variant to the VFS that allows passing in the maximum file size of the file system, instead of always using maxbytes from the superblock. This can be used to eliminate some cut'n'paste seek code in ext4. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
-rw-r--r--fs/read_write.c37
-rw-r--r--include/linux/fs.h2
2 files changed, 30 insertions, 9 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 672b187def62..dfd125798791 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -51,23 +51,23 @@ static loff_t lseek_execute(struct file *file, struct inode *inode,
}
/**
- * generic_file_llseek - generic llseek implementation for regular files
+ * generic_file_llseek_size - generic llseek implementation for regular files
* @file: file structure to seek on
* @offset: file offset to seek to
* @origin: type of seek
+ * @size: max size of file system
*
- * This is a generic implemenation of ->llseek usable for all normal local
- * filesystems. It just updates the file offset to the value specified by
- * @offset and @origin under i_mutex.
+ * This is a variant of generic_file_llseek that allows passing in a custom
+ * file size.
*
* Synchronization:
- * SEEK_SET is unsynchronized (but atomic on 64bit platforms)
+ * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
* SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
* read/writes behave like SEEK_SET against seeks.
- * SEEK_END
*/
loff_t
-generic_file_llseek(struct file *file, loff_t offset, int origin)
+generic_file_llseek_size(struct file *file, loff_t offset, int origin,
+ loff_t maxsize)
{
struct inode *inode = file->f_mapping->host;
@@ -91,7 +91,7 @@ generic_file_llseek(struct file *file, loff_t offset, int origin)
*/
spin_lock(&file->f_lock);
offset = lseek_execute(file, inode, file->f_pos + offset,
- inode->i_sb->s_maxbytes);
+ maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
@@ -113,7 +113,26 @@ generic_file_llseek(struct file *file, loff_t offset, int origin)
break;
}
- return lseek_execute(file, inode, offset, inode->i_sb->s_maxbytes);
+ return lseek_execute(file, inode, offset, maxsize);
+}
+EXPORT_SYMBOL(generic_file_llseek_size);
+
+/**
+ * generic_file_llseek - generic llseek implementation for regular files
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @origin: type of seek
+ *
+ * This is a generic implemenation of ->llseek useable for all normal local
+ * filesystems. It just updates the file offset to the value specified by
+ * @offset and @origin under i_mutex.
+ */
+loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct inode *inode = file->f_mapping->host;
+
+ return generic_file_llseek_size(file, offset, origin,
+ inode->i_sb->s_maxbytes);
}
EXPORT_SYMBOL(generic_file_llseek);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index db85196f6308..d055cc7d7240 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2403,6 +2403,8 @@ file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
extern loff_t noop_llseek(struct file *file, loff_t offset, int origin);
extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
+extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
+ int origin, loff_t maxsize);
extern int generic_file_open(struct inode * inode, struct file * filp);
extern int nonseekable_open(struct inode * inode, struct file * filp);

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