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Subject[PATCH v1.2 0/5] IMA: making i_readcount a first class inode citizen (reposting)
Reposting unchanged, but with Eric's Ack and suggestion. 

This patchset separates the incrementing/decrementing of the i_readcount, in
the VFS layer, from other IMA functionality, by replacing the current
ima_counts_get() call with i_readcount_inc(). Its unclear whether this call to
increment i_readcount should be made earlier, like i_writecount. Currently the
call is situated immediately after the switch from put_filp() to fput() for

The patch ordering is a bit redundant in order to leave removing the ifdef
around i_readcount until the last patch. The first four patches: redefines
i_readcount as atomic, defines i_readcount_inc/dec(), moves the IMA
functionality in ima_counts_get() to ima_file_check(), and removes the IMA
imbalance code, simplifying IMA. The last patch removes the ifdef around
i_readcount, making i_readcount into a "first class inode citizen".

The generic_setlease code could then take advantage of i_readcount to help
eliminate some of the race conditions, but not all. For now, Eric suggested
upstreaming patches 1-4 and leaving the 5th patch until there is a second user.
Then we can either unconditionally compile it in, or we can wrap it in
something that either user can select in the Kconfig. Both Bruce and I agree
with his suggestion.

- renamed iget/iput_readcount to i_readcount_inc/dec (Dave Chinner's suggestion)
- finished cleaning up the locking, so that: (based on Eric's comment.)
- i_lock is not required
- i_mutex is taken when making measurement decisions to prevent
file metadata(eg. permissions, xattr) changing from under it.
- iint->mutex is taken when accessing/modifying the iint structure.
- Based on the previous posting discussion, i_readcount is now defined as


Mimi Zohar (5):
IMA: convert i_readcount to atomic
IMA: define readcount functions
IMA: maintain i_readcount in the VFS layer
IMA: remove IMA imbalance checking
IMA: making i_readcount a first class inode citizen

fs/file_table.c | 5 +-
fs/open.c | 3 +-
include/linux/fs.h | 16 ++++-
include/linux/ima.h | 6 --
security/integrity/ima/ima_iint.c | 5 --
security/integrity/ima/ima_main.c | 130 ++++---------------------------------
6 files changed, 31 insertions(+), 134 deletions(-)


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