159 lines
4.6 KiB
Diff
159 lines
4.6 KiB
Diff
From: David Sterba <dsterba@suse.cz>
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Date: Tue, 28 Jun 2011 12:38:06 +0200
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Patch-mainline: pending
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References: FATE#306586
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Subject: [PATCH] btrfs: add new ioctl to determine size of compressed file
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Go through all extents of a file in a given [start,end) range and sum
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for:
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* regular extent: ->block_len, size is already rounded up to blocks
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* inline extents: length rounded up to 512
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The range is start inclusive / end exclusive. For whole a file pass
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0 and (u64)-1.
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The values returned are number of occupied 512B sectors for uncompressed
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and compressed size and can be easily compared to determine rough
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compression ratio of the given file range.
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Based on implementation from Ulrich Hecht,
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http://comments.gmane.org/gmane.comp.file-systems.btrfs/6253
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Signed-off-by: David Sterba <dsterba@suse.cz>
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---
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fs/btrfs/ioctl.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
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fs/btrfs/ioctl.h | 12 ++++++++
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2 files changed, 95 insertions(+), 0 deletions(-)
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diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
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index c04f02c..91e6ab8 100644
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--- a/fs/btrfs/ioctl.c
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+++ b/fs/btrfs/ioctl.c
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@@ -2972,6 +2972,86 @@ static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
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return 0;
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}
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+/*
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+ * Returns the compressed size of an inode in 512 byte blocks.
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+ * Count the on-disk space used by extents starting in range [start, end),
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+ * inline data are rounded up to sector, ie. 512.
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+ *
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+ * The range is start inclusive and end exclusive so it can be used to
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+ * determine compressed size of a given extent by its start and start of the
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+ * next extent easily, without counting length.
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+ * Whole file is specified as start = 0, end = (u64)-1
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+ */
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+static long btrfs_ioctl_compr_size(struct file *file, void __user *argp)
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+{
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+ struct inode *inode = fdentry(file)->d_inode;
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+ struct btrfs_ioctl_compr_size_args compr_args;
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+ u64 len;
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+ u64 compressed_size = 0;
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+ u64 size = 0;
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+ u64 offset = 0;
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+
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+ if (S_ISDIR(inode->i_mode))
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+ return -EISDIR;
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+
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+ if (copy_from_user(&compr_args, argp,
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+ sizeof(struct btrfs_ioctl_compr_size_args)))
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+ return -EFAULT;
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+
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+ if (compr_args.start > compr_args.end)
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+ return -EINVAL;
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+
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+ mutex_lock(&inode->i_mutex);
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+
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+ offset = compr_args.start;
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+ if (inode->i_size > compr_args.end)
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+ len = compr_args.end;
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+ else
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+ len = inode->i_size;
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+
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+ /*
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+ * do any pending delalloc/csum calc on inode, one way or
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+ * another, and lock file content
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+ */
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+ btrfs_wait_ordered_range(inode, compr_args.start, len);
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+
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+ lock_extent(&BTRFS_I(inode)->io_tree, compr_args.start, len, GFP_NOFS);
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+
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+ while (offset < len) {
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+ struct extent_map *em;
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+
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+ em = btrfs_get_extent(inode, NULL, 0, offset, 1, 0);
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+ if (IS_ERR_OR_NULL(em))
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+ goto error;
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+ if (em->block_len != (u64)-1) {
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+ compressed_size += em->block_len;
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+ size += ALIGN(em->len, inode->i_sb->s_blocksize);
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+ } else if (em->block_start == EXTENT_MAP_INLINE) {
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+ compressed_size += ALIGN(em->len, 512);
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+ size += ALIGN(em->len, 512);
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+ }
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+ offset += em->len;
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+ free_extent_map(em);
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+ }
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+ unlock_extent(&BTRFS_I(inode)->io_tree, compr_args.start, len, GFP_NOFS);
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+ mutex_unlock(&inode->i_mutex);
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+
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+ compr_args.size = size >> 9;
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+ compr_args.compressed_size = compressed_size >> 9;
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+
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+ if (copy_to_user(argp, &compr_args,
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+ sizeof(struct btrfs_ioctl_compr_size_args)))
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+ return -EFAULT;
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+
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+ return 0;
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+
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+error:
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+ unlock_extent(&BTRFS_I(inode)->io_tree, compr_args.start, len, GFP_NOFS);
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+ mutex_unlock(&inode->i_mutex);
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+
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+ return -EIO;
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+}
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+
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static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
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void __user *arg)
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{
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@@ -3110,6 +3190,8 @@ long btrfs_ioctl(struct file *file, unsigned int
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return btrfs_ioctl_scrub_cancel(root, argp);
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case BTRFS_IOC_SCRUB_PROGRESS:
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return btrfs_ioctl_scrub_progress(root, argp);
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+ case BTRFS_IOC_COMPR_SIZE:
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+ return btrfs_ioctl_compr_size(file, argp);
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}
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return -ENOTTY;
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diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
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--- a/fs/btrfs/ioctl.h
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+++ b/fs/btrfs/ioctl.h
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@@ -217,6 +217,16 @@ struct btrfs_ioctl_logical_ino_args {
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__u64 inodes;
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};
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+struct btrfs_ioctl_compr_size_args {
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+ /* Range start, inclusive */
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+ __u64 start; /* in */
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+ /* Range end, exclusive */
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+ __u64 end; /* in */
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+ __u64 size; /* out */
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+ __u64 compressed_size; /* out */
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+ __u64 reserved[2];
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+};
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+
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#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
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struct btrfs_ioctl_vol_args)
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#define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
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@@ -276,5 +286,7 @@ struct btrfs_ioctl_logical_ino_args {
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struct btrfs_ioctl_ino_path_args)
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#define BTRFS_IOC_LOGICAL_INO _IOWR(BTRFS_IOCTL_MAGIC, 36, \
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struct btrfs_ioctl_ino_path_args)
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+#define BTRFS_IOC_COMPR_SIZE _IOR(BTRFS_IOCTL_MAGIC, 51, \
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+ struct btrfs_ioctl_compr_size_args)
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#endif
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--
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1.7.7.3
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