ext4: allow readdir()'s of large empty directories to be interrupted

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If a directory has a large number of empty blocks, iterating over all
of them can take a long time, leading to scheduler warnings and users
getting irritated when they can't kill a process in the middle of one
of these long-running readdir operations.  Fix this by adding checks to
ext4_readdir() and ext4_htree_fill_tree().

This was reverted earlier due to a typo in the original commit where I
experimented with using signal_pending() instead of
fatal_signal_pending().  The test was in the wrong place if we were
going to return signal_pending() since we would end up returning
duplicant entries.  See 9f2394c9be for a more detailed explanation.

Added fix as suggested by Linus to check for signal_pending() in
in the filldir() functions.

Reported-by: Benjamin LaHaise <bcrl@kvack.org>
Google-Bug-Id: 27880676
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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This commit is contained in:

Theodore Ts'o 2016-04-23 22:50:07 -04:00

parent c3b46c7326

commit 1f60fbe727

4 changed files with 18 additions and 0 deletions

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4

fs/compat.c

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5

fs/ext4/dir.c

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5

fs/ext4/namei.c

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4

fs/readdir.c

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