[2659] | 1 | From b1f23baecb2de72b44cda8bba27615c012a445f1 Mon Sep 17 00:00:00 2001 |
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[2655] | 2 | From: Marc Dionne <marc.dionne@your-file-system.com> |
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| 3 | Date: Thu, 18 Dec 2014 08:43:22 -0500 |
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| 4 | Subject: [PATCH] Linux: d_splice_alias may drop inode reference on error |
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| 5 | |
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| 6 | d_splice_alias now drops the inode reference on error, so we |
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| 7 | need to grab an extra one to make sure that the inode doesn't |
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| 8 | go away, and release it when done if there was no error. |
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| 9 | |
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| 10 | For kernels that may not drop the reference, provide an |
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| 11 | additional iput() within an ifdef. This could be hooked up |
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| 12 | to a configure option to allow building a module for a kernel |
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| 13 | that is known not to drop the reference on error. That hook |
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| 14 | is not provided here. Affected kernels should be the early |
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| 15 | 3.17 ones (3.17 - 3.17.2); 3.16 and older kernels should not |
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| 16 | return errors here. |
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| 17 | |
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| 18 | Change-Id: Id1786ac2227b4d8e0ae801fe59c15a0ecd975bed |
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| 19 | --- |
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[2659] | 20 | acinclude.m4 | 3 +++ |
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| 21 | src/afs/LINUX/osi_vnodeops.c | 29 ++++++++++++++++++++++++++--- |
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| 22 | 2 files changed, 29 insertions(+), 3 deletions(-) |
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[2655] | 23 | |
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[2659] | 24 | diff --git a/acinclude.m4 b/acinclude.m4 |
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| 25 | index 96adde0..19f7092 100644 |
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| 26 | --- a/acinclude.m4 |
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| 27 | +++ b/acinclude.m4 |
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| 28 | @@ -984,6 +984,9 @@ case $AFS_SYSNAME in *_linux* | *_umlinux*) |
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| 29 | AC_CHECK_LINUX_FUNC([hlist_unhashed], |
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| 30 | [#include <linux/list.h>], |
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| 31 | [hlist_unhashed(0);]) |
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| 32 | + AC_CHECK_LINUX_FUNC([ihold], |
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| 33 | + [#include <linux/fs.h>], |
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| 34 | + [ihold(NULL);]) |
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| 35 | AC_CHECK_LINUX_FUNC([i_size_read], |
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| 36 | [#include <linux/fs.h>], |
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| 37 | [i_size_read(NULL);]) |
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[2655] | 38 | diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c |
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[2659] | 39 | index b2ab9d5..cedfef6 100644 |
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[2655] | 40 | --- a/src/afs/LINUX/osi_vnodeops.c |
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| 41 | +++ b/src/afs/LINUX/osi_vnodeops.c |
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[2659] | 42 | @@ -1612,6 +1612,17 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp) |
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[2655] | 43 | ip->i_flags |= S_AUTOMOUNT; |
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| 44 | #endif |
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| 45 | } |
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| 46 | + /* |
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| 47 | + * Take an extra reference so the inode doesn't go away if |
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| 48 | + * d_splice_alias drops our reference on error. |
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| 49 | + */ |
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| 50 | + if (ip) |
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[2659] | 51 | +#ifdef HAVE_LINUX_IHOLD |
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| 52 | + ihold(ip); |
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| 53 | +#else |
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[2655] | 54 | + igrab(ip); |
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[2659] | 55 | +#endif |
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[2655] | 56 | + |
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| 57 | newdp = d_splice_alias(ip, dp); |
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| 58 | |
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| 59 | done: |
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[2659] | 60 | @@ -1625,14 +1636,26 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp) |
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[2655] | 61 | * d_splice_alias can return an error (EIO) if there is an existing |
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| 62 | * connected directory alias for this dentry. |
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| 63 | */ |
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| 64 | - if (!IS_ERR(newdp)) |
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| 65 | + if (!IS_ERR(newdp)) { |
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| 66 | + iput(ip); |
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| 67 | return newdp; |
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| 68 | - else { |
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| 69 | + } else { |
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| 70 | d_add(dp, ip); |
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| 71 | + /* |
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| 72 | + * Depending on the kernel version, d_splice_alias may or may |
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| 73 | + * not drop the inode reference on error. If it didn't, do it |
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| 74 | + * here. |
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| 75 | + */ |
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| 76 | +#if defined(D_SPLICE_ALIAS_LEAK_ON_ERROR) |
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| 77 | + iput(ip); |
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| 78 | +#endif |
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| 79 | return NULL; |
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| 80 | } |
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| 81 | - } else |
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| 82 | + } else { |
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| 83 | + if (ip) |
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| 84 | + iput(ip); |
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| 85 | return ERR_PTR(afs_convert_code(code)); |
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| 86 | + } |
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| 87 | } |
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| 88 | |
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| 89 | static int |
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| 90 | -- |
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| 91 | 2.2.1 |
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| 92 | |
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