On 2010-02-24, at 01:49, Schrittesser, Florian wrote:
i wanted to ask you all about the exact overwrite mechanism used in
ext3; is the information in the datablocks overwritten or written to
a new location and the information in the referring inode is
changed? Is it depending on the application used (and the functions
it calls) or independent from that?
Please don't hesitate to go into further details and thanks for your
It depends on what your application is doing. If it is opening the
file with open(O_TRUNC) then writing it, the new data is written to
wherever it is allocated. If O_TRUNC is not used, then the data is
written into the same blocks as were previously allocated to the file.
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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