On 08/08/2014 07:07 AM, Ján Tomko wrote:
On 08/05/2014 04:38 PM, John Ferlan wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=1077068
Check for the NFS FS type being true for a "local" stat of the file to force usage of the 'st_size' value rather than calculating the size using the 'st_blocks' and 'st_blksize'. As described in the stat(2) man page:
"Use of the st_blocks and st_blksize fields may be less portable."
experimentation shows a 10M file could get the following output from stat:
st_size=10485760 st_blocks=88 st_blksize=1048576
resulting in a "44 KiB" value being displayed as the allocation value. While this value does match the "du -s" value of the same file, the "du -b" value shows the "st_size" field. Similarly a long listing of the file shows the 10M size.
Capacity should be the apparent size (what du -b shows, or st_size), while allocation should track the on-disk usage (du, st_blocks * 512).
It looks to me that the values are correct, it's just that posix_fallocate does neither work nor fail on NFS.
Jan
Testing seems to indicate that posix_fallocate() either doesn't work as expected on the target or using the target.path is incorrect... Before posix_fallocate stat st_blocks=0 st_blksize=1048576 st_size=10485760 lseek end=10485760 posix_fallocate of 10485760 bytes on /home/nfs_pool/target/test-vol1 After posix_fallocate stat st_blocks=88 st_blksize=1048576 st_size=10485760 lseek end=10485760 Hmm... would going at the target be correct in this instance? Same test but use the source path: Before posix_fallocate stat st_blocks=0 st_blksize=4096 st_size=10485760 lseek end=10485760 posix_fallocate of 10485760 bytes on /home/nfs_pool/nfs-export/test-vol1 After posix_fallocate stat st_blocks=20480 st_blksize=4096 st_size=10485760 lseek end=10485760 ... hmm.... 20480 * 512 = 10485760 # df ... localhost:/home/nfs_pool/nfs-export 140979200 35521536 98273280 27% /home/nfs_pool/target # John