Merge patch series "cheaper MAY_EXEC handling for path lookup"

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Mateusz Guzik <mjguzik@gmail.com> says:

In short, MAY_WRITE checks are elided.

This obsoletes the idea of pre-computing if perm checks are necessary as
that turned out to be too hairy. The new code has 2 more branches per
path component compared to that idea, but the perf difference for
typical paths (< 6 components) was basically within noise. To be
revisited if someone(tm) removes other slowdowns.

Instead of the pre-computing thing I added IOP_FASTPERM_MAY_EXEC so that
filesystems like btrfs can still avoid the hard work.

* patches from https://patch.msgid.link/20251107142149.989998-1-mjguzik@gmail.com:
  fs: retire now stale MAY_WRITE predicts in inode_permission()
  btrfs: utilize IOP_FASTPERM_MAY_EXEC
  fs: speed up path lookup with cheaper handling of MAY_EXEC

Link: https://patch.msgid.link/20251107142149.989998-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

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Christian Brauner 2025-11-11 10:38:44 +01:00

parent 854e8df2ce a0a28c4e41

commit 04f0955b60

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12

fs/btrfs/inode.c

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47

fs/namei.c

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13

include/linux/fs.h

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