On the BeeGFS Mailing list there is a report claiming BTRFS is not usable with BeeGFS, as BeeGFS is using statfs output to determine the number of total and free inodes. BeeGFS needs the number of free inodes as it stores its meta-data either in extended attributes of the underlying file-system or directly in an inline inode. According to the BeeGFS Server Tuning Guide: """ BeeGFS metadata is stored as extended attributes (EAs) on the underlying file system to optimal performance. One metadata file will be created for each file that a user creates. About extended attributes usage: BeeGFS Metadata files have a size of 0 bytes (i.e. no normal file contents). Access to extended attributes is possible with the getfattr tool. If the inodes of the underlying file system are sufficiently large, EAs can be inlined into the inode of the underlying file system. Additional data blocks are then not required anymore and metadata disk usage will be reduced. With EAs inlined into the inode, access latencies are reduced as seeking to an extra data block is not required anymore. """ Provide some estimated numbers of total and free inodes in statfs by dividing the number of blocks by the size of an inode-item for the total number of possible inodes and for the number of free inodes divide the number of free blocks by the size of an inode-item, similar to what other file-systems without a fixed number of inodes do. This of is just an estimation and should not be relied upon. Without the patch applied: rapido1:/# df -hTi /mnt/test Filesystem Type Inodes IUsed IFree IUse% Mounted on /mnt/test btrfs 0 0 0 - /mnt/test With the patch applied on an empty fs: rapido1:/# df -hTi /mnt/test Filesystem Type Inodes IUsed IFree IUse% Mounted on /dev/zram0 btrfs 1.6K 0 1.6K 0% /mnt/test With the patch applied on a dirty fs: rapido1:/# df -hTi /mnt/test Filesystem Type Inodes IUsed IFree IUse% Mounted on /dev/zram0 btrfs 1.6K 1.5K 197 88% /mnt/test Link: https://groups.google.com/forum/#!msg/fhgfs-user/IJqGS5o1UD0/8ftDdUI3AQAJ Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx> --- fs/btrfs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index b818f764c1c9..6f6f6a70eb1e 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2068,6 +2068,8 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor); buf->f_blocks >>= bits; buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits); + buf->f_files = div_u64(buf->f_blocks, sizeof(struct btrfs_inode_item)); + buf->f_ffree = div_u64(buf->f_bfree, sizeof(struct btrfs_inode_item)); /* Account global block reserve as used, it's in logical size already */ spin_lock(&block_rsv->lock); -- 2.16.4
