Ext4 Punch Hole Support: Enable Punch Hole

PATCH Superseded Allison Henderson 1 participant 1 message May 3, 2011 ext4 file system

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Allison Henderson

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2011-05-03 16:48 UTC #0 lore raw

PATCH v6 5/5 Ext4 Punch Hole Support: Enable Punch Hole

This patch adds new routines: "ext4_punch_hole" "ext4_ext_punch_hole" and "ext4_ext_check_cache"

fallocate has been modified to call ext4_punch_hole when the punch hole flag is passed. At the moment, we only support punching holes in extents, so this routine is pretty much a wrapper for the ext4_ext_punch_hole routine.

The ext4_ext_punch_hole routine first completes all outstanding writes with the associated pages, and then releases them. The unblock aligned data is zeroed, and all blocks in between are punched out.

v5->v6:
The ext4_ext_check_cache routine is very similar to ext4_ext_in_cache but it accepts a ext4_ext_cache parameter instead of a ext4_extent parameter. This routine is used by ext4_ext_punch_hole to check and see if a block in a hole that has been cached. The ext4_ext_cache parameter is necessary because the members ext4_extent structure are not large enough to hold a 32 bit value. The existing ext4_ext_in_cache routine has become a wrapper to this new function.

Signed-off-by Allison Henderson <[email protected]>

---
:100644 100644 45136d8... 04c3dc2... M fs/ext4/ext4.h
:100644 100644 7f0fcc1... 4a7b9e0... M fs/ext4/extents.c
:100644 100644 dc45631... d4305aa... M fs/ext4/inode.c

 fs/ext4/ext4.h    |    3 +
 fs/ext4/extents.c |  240 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 fs/ext4/inode.c   |   25 ++++++
 3 files changed, 257 insertions(+), 11 deletions(-)

fs/ext4/ext4.h +3 -0

index 45136d8..04c3dc2 100644
@@ -1734,6 +1734,7 @@ extern int ext4_change_inode_journal_flag(struct inode *, int);
 extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
 extern int ext4_can_truncate(struct inode *inode);
 extern void ext4_truncate(struct inode *);
+extern int ext4_punch_hole(struct file *file, loff_t offset, loff_t length);
 extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
 extern void ext4_get_inode_flags(struct ext4_inode_info *);

@@ -2071,6 +2072,8 @@ extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
 extern int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 			       struct ext4_map_blocks *map, int flags);
 extern void ext4_ext_truncate(struct inode *);
+extern int ext4_ext_punch_hole(struct file *file, loff_t offset,
+				loff_t length);
 extern void ext4_ext_init(struct super_block *);
 extern void ext4_ext_release(struct super_block *);
 extern long ext4_fallocate(struct file *file, int mode, loff_t offset,

fs/ext4/extents.c +229 ~~-11~~

275 lines not on this page · raw message

fs/ext4/inode.c +25 -0

index dc45631..d4305aa 100644
@@ -4420,6 +4420,31 @@ int ext4_can_truncate(struct inode *inode)
 }
 
 /*
+ * ext4_punch_hole: punches a hole in a file by releaseing the blocks
+ * associated with the given offset and length
+ *
+ * @inode:  File inode
+ * @offset: The offset where the hole will begin
+ * @len:    The length of the hole
+ *
+ * Returns: 0 on sucess or negative on failure
+ */
+
+int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	if (!S_ISREG(inode->i_mode))
+		return -ENOTSUPP;
+
+	if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		/* TODO: Add support for non extent hole punching */
+		return -ENOTSUPP;
+	}
+
+	return ext4_ext_punch_hole(file, offset, length);
+}
+
+/*
  * ext4_truncate()
  *
  * We block out ext4_get_block() block instantiations across the entire

Signature · 1 line

1.7.1