[2/3] btrfs-progs: add 'du' command

Commit Message

Jérôme Poulin Feb. 25, 2016, 8:57 a.m. UTC

On Wed, Jan 20, 2016 at 4:49 PM, Mark Fasheh <[e-mail]> wrote:
> 'btrfs du' differs from regular du in that it will work to resolve which
> blocks are shared between files in its list. This gives the user a more
> accurate bytecount from which they can make decisions regarding management
> of their file space.


Would it be a good idea for this new du to show the compressed file size too?

It was not made by me but I know I had this patch lying around, it
also does not compile right now but I could give it an update. The
wiki says this patch was "not merged yet" but I have no idea why it
was not since it was working correctly 2 years ago on my machine.

---
 fs/btrfs/ioctl.c           | 77 ++++++++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/btrfs.h |  2 ++
 2 files changed, 79 insertions(+)

 #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \

Comments

David Sterba Feb. 25, 2016, 9:25 a.m. UTC | #1

On Thu, Feb 25, 2016 at 03:57:51AM -0500, Jérôme Poulin wrote:
> On Wed, Jan 20, 2016 at 4:49 PM, Mark Fasheh <[e-mail]> wrote:
> > 'btrfs du' differs from regular du in that it will work to resolve which
> > blocks are shared between files in its list. This gives the user a more
> > accurate bytecount from which they can make decisions regarding management
> > of their file space.
> 
> 
> Would it be a good idea for this new du to show the compressed file size too?

Yes, we're ware of the demand for that. IMO it's not necessary for the
initial implementation.

> It was not made by me but I know I had this patch lying around, it
> also does not compile right now but I could give it an update. The
> wiki says this patch was "not merged yet" but I have no idea why it
> was not since it was working correctly 2 years ago on my machine.

The patch looks familiar to me. The ioctl for compressed size approach
was abandoned in favor of extending FIEMAP. For the purposes of 'fi du'
we'll probably use the SEARCH_TREE ioctl and iterate the extents
manually.
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Patch

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index da94138..1c6285b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4499,6 +4499,81 @@  static int build_ino_list(u64 inum, u64 offset,
u64 root, void *ctx)
     return 0;
 }

+/*
+ * Returns the compressed size of an inode in 512 byte blocks.
+ * Count the on-disk space used by extents starting in range [start, end),
+ * inline data are rounded up to sector, ie. 512.
+ *
+ * The range is start inclusive and end exclusive so it can be used to
+ * determine compressed size of a given extent by its start and start of the
+ * next extent easily, without counting length.
+ * Whole file is specified as start = 0, end = (u64)-1
+ */
+static long btrfs_ioctl_compr_size(struct file *file, void __user *argp)
+{
+    struct inode *inode = fdentry(file)->d_inode;
+    struct btrfs_ioctl_compr_size_args compr_args;
+    u64 len;
+    u64 compressed_size = 0;
+    u64 offset = 0;
+
+    if (S_ISDIR(inode->i_mode))
+        return -EISDIR;
+
+    if (copy_from_user(&compr_args, argp,
+                sizeof(struct btrfs_ioctl_compr_size_args)))
+        return -EFAULT;
+
+    if (compr_args.start > compr_args.end)
+        return -EINVAL;
+
+    mutex_lock(&inode->i_mutex);
+
+    offset = compr_args.start;
+    if (inode->i_size > compr_args.end)
+        len = compr_args.end;
+    else
+        len = inode->i_size;
+
+    /*
+     * do any pending delalloc/csum calc on inode, one way or
+     * another, and lock file content
+     */
+    btrfs_wait_ordered_range(inode, compr_args.start, len);
+
+    while (offset < len) {
+        struct extent_map *em;
+
+        em = btrfs_get_extent(inode, NULL, 0, offset, 1, 0);
+        if (IS_ERR_OR_NULL(em))
+            goto error;
+        if (em->block_len != (u64)-1)
+            compressed_size += em->block_len;
+        else if (em->block_start == EXTENT_MAP_INLINE) {
+            compressed_size += ALIGN(em->len, 512);
+        }
+        offset += em->len;
+        free_extent_map(em);
+    }
+    mutex_unlock(&inode->i_mutex);
+
+    unlock_extent(&BTRFS_I(inode)->io_tree, compr_args.start, len);
+
+    compr_args.size = compressed_size >> 9;
+
+    if (copy_to_user(argp, &compr_args, sizeof(struct
+                    btrfs_ioctl_compr_size_args)))
+        return -EFAULT;
+
+    return 0;
+
+error:
+    mutex_unlock(&inode->i_mutex);
+    unlock_extent(&BTRFS_I(inode)->io_tree, compr_args.start, len);
+
+    return -EIO;
+}
+
 static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
                     void __user *arg)
 {
@@ -5532,6 +5607,8 @@  long btrfs_ioctl(struct file *file, unsigned int
         return btrfs_ioctl_scrub_progress(root, argp);
     case BTRFS_IOC_BALANCE_V2:
         return btrfs_ioctl_balance(file, argp);
+    case BTRFS_IOC_COMPR_SIZE:
+        return btrfs_ioctl_compr_size(file, argp);
     case BTRFS_IOC_BALANCE_CTL:
         return btrfs_ioctl_balance_ctl(root, arg);
     case BTRFS_IOC_BALANCE_PROGRESS:
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index dea8931..cd52cda 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -647,6 +647,8 @@  static inline char *btrfs_err_str(enum
btrfs_err_code err_code)
                    char[BTRFS_LABEL_SIZE])
 #define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 50, \
                    char[BTRFS_LABEL_SIZE])
+#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 51, \
+                struct btrfs_ioctl_compr_size_args)
 #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
                       struct btrfs_ioctl_get_dev_stats)