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ec00022030
When an xattr block has a single reference, block is updated inplace
and it is reinserted to the cache. Later, a cache lookup is performed
to see whether an existing block has the same contents. This cache
lookup will most of the time return the just inserted entry so
deduplication is not achieved.
Running the following test script will produce two xattr blocks which
can be observed in "File ACL: " line of debugfs output:
mke2fs -b 1024 -I 128 -F -O extent /dev/sdb 1G
mount /dev/sdb /mnt/sdb
touch /mnt/sdb/{x,y}
setfattr -n user.1 -v aaa /mnt/sdb/x
setfattr -n user.2 -v bbb /mnt/sdb/x
setfattr -n user.1 -v aaa /mnt/sdb/y
setfattr -n user.2 -v bbb /mnt/sdb/y
debugfs -R 'stat x' /dev/sdb | cat
debugfs -R 'stat y' /dev/sdb | cat
This patch defers the reinsertion to the cache so that we can locate
other blocks with the same contents.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.