vfs: export lseek_execute() to modules
For those file systems(btrfs/ext4/ocfs2/tmpfs) that support
SEEK_DATA/SEEK_HOLE functions, we end up handling the similar
matter in lseek_execute() to update the current file offset
to the desired offset if it is valid, ceph also does the
simliar things at ceph_llseek().
To reduce the duplications, this patch make lseek_execute()
public accessible so that we can call it directly from the
underlying file systems.
Thanks Dave Chinner for this suggestion.
[AV: call it vfs_setpos(), don't bring the removed 'inode' argument back]
v2->v1:
- Add kernel-doc comments for lseek_execute()
- Call lseek_execute() in ceph->llseek()
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Cc: Ben Myers <bpm@sgi.com>
Cc: Ted Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Sage Weil <sage@inktank.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 4205ba7..89da56a 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2425,20 +2425,7 @@
}
}
- if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
- offset = -EINVAL;
- goto out;
- }
- if (offset > inode->i_sb->s_maxbytes) {
- offset = -EINVAL;
- goto out;
- }
-
- /* Special lock needed here? */
- if (offset != file->f_pos) {
- file->f_pos = offset;
- file->f_version = 0;
- }
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
out:
mutex_unlock(&inode->i_mutex);
return offset;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 656e169..16c989d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -866,16 +866,7 @@
break;
}
- if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
- offset = -EINVAL;
- goto out;
- }
-
- /* Special lock needed here? */
- if (offset != file->f_pos) {
- file->f_pos = offset;
- file->f_version = 0;
- }
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
out:
mutex_unlock(&inode->i_mutex);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index b1b4d51..469361d 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -494,17 +494,7 @@
if (dataoff > isize)
return -ENXIO;
- if (dataoff < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
- return -EINVAL;
- if (dataoff > maxsize)
- return -EINVAL;
-
- if (dataoff != file->f_pos) {
- file->f_pos = dataoff;
- file->f_version = 0;
- }
-
- return dataoff;
+ return vfs_setpos(file, dataoff, maxsize);
}
/*
@@ -580,17 +570,7 @@
if (holeoff > isize)
holeoff = isize;
- if (holeoff < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
- return -EINVAL;
- if (holeoff > maxsize)
- return -EINVAL;
-
- if (holeoff != file->f_pos) {
- file->f_pos = holeoff;
- file->f_version = 0;
- }
-
- return holeoff;
+ return vfs_setpos(file, holeoff, maxsize);
}
/*
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 8a38714..41000f2 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2646,17 +2646,7 @@
goto out;
}
- if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
- ret = -EINVAL;
- if (!ret && offset > inode->i_sb->s_maxbytes)
- ret = -EINVAL;
- if (ret)
- goto out;
-
- if (offset != file->f_pos) {
- file->f_pos = offset;
- file->f_version = 0;
- }
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
out:
mutex_unlock(&inode->i_mutex);
diff --git a/fs/read_write.c b/fs/read_write.c
index 37d16e8..122a384 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -41,7 +41,19 @@
return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
-static loff_t lseek_execute(struct file *file, loff_t offset, loff_t maxsize)
+/**
+ * vfs_setpos - update the file offset for lseek
+ * @file: file structure in question
+ * @offset: file offset to seek to
+ * @maxsize: maximum file size
+ *
+ * This is a low-level filesystem helper for updating the file offset to
+ * the value specified by @offset if the given offset is valid and it is
+ * not equal to the current file offset.
+ *
+ * Return the specified offset on success and -EINVAL on invalid offset.
+ */
+loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
@@ -54,6 +66,7 @@
}
return offset;
}
+EXPORT_SYMBOL(vfs_setpos);
/**
* generic_file_llseek_size - generic llseek implementation for regular files
@@ -94,7 +107,7 @@
* like SEEK_SET.
*/
spin_lock(&file->f_lock);
- offset = lseek_execute(file, file->f_pos + offset, maxsize);
+ offset = vfs_setpos(file, file->f_pos + offset, maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
@@ -116,7 +129,7 @@
break;
}
- return lseek_execute(file, offset, maxsize);
+ return vfs_setpos(file, offset, maxsize);
}
EXPORT_SYMBOL(generic_file_llseek_size);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 0ad2b95..de3dc98 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1268,8 +1268,7 @@
}
out:
- if (offset != file->f_pos)
- file->f_pos = offset;
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
out_unlock:
xfs_iunlock_map_shared(ip, lock);
@@ -1377,8 +1376,7 @@
* situation in particular.
*/
offset = min_t(loff_t, offset, isize);
- if (offset != file->f_pos)
- file->f_pos = offset;
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
out_unlock:
xfs_iunlock_map_shared(ip, lock);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a137a73..bccb192 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2426,6 +2426,7 @@
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 whence);
extern loff_t no_llseek(struct file *file, loff_t offset, int whence);
+extern loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize);
extern loff_t generic_file_llseek(struct file *file, loff_t offset, int whence);
extern loff_t generic_file_llseek_size(struct file *file, loff_t offset,
int whence, loff_t maxsize, loff_t eof);
diff --git a/mm/shmem.c b/mm/shmem.c
index f887358..118dfa4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1798,10 +1798,7 @@
}
}
- if (offset >= 0 && offset != file->f_pos) {
- file->f_pos = offset;
- file->f_version = 0;
- }
+ offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
mutex_unlock(&inode->i_mutex);
return offset;
}
